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class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class=menu__link tabindex=0 href=/docs/next/guide/xlang/troubleshooting><span title=Troubleshooting class=linkLabel_WmDU>Troubleshooting</span></a></ul></ul></ul></nav></div></div></aside><main class=docMainContainer_TBSr><div class="container padding-top--md padding-bottom--lg"><div class=row><div class="col docItemCol_VOVn"><div class="theme-doc-version-banner alert alert--warning margin-bottom--md" role=alert><div>This is unreleased documentation for <!-- -->Apache Fory™<!-- --> <b>dev</b> version.</div><div class=margin-top--md>For up-to-date documentation, see the <b><a href=/docs/guide/xlang/reference_tracking>latest version</a></b> (<!-- -->1.3.0<!-- -->).</div></div><div class=docItemContainer_Djhp><article><nav class="theme-doc-breadcrumbs breadcrumbsContainer_Z_bl" aria-label=Breadcrumbs><ul class=breadcrumbs><li class=breadcrumbs__item><a aria-label="Home page" class=breadcrumbs__link href=/><svg viewBox="0 0 24 24" class=breadcrumbHomeIcon_YNFT><path d="M10 19v-5h4v5c0 .55.45 1 1 1h3c.55 0 1-.45 1-1v-7h1.7c.46 0 .68-.57.33-.87L12.67 3.6c-.38-.34-.96-.34-1.34 0l-8.36 7.53c-.34.3-.13.87.33.87H5v7c0 .55.45 1 1 1h3c.55 0 1-.45 1-1z" fill=currentColor /></svg></a><li class=breadcrumbs__item><span class=breadcrumbs__link>Guide</span><li class=breadcrumbs__item><a class=breadcrumbs__link href=/docs/next/guide/xlang/><span>Cross Language</span></a><li class="breadcrumbs__item breadcrumbs__item--active"><span class=breadcrumbs__link>Reference Tracking</span></ul></nav><span class="theme-doc-version-badge badge badge--secondary">Version: dev</span><div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type=button class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div class="theme-doc-markdown markdown"><header><h1>Reference Tracking</h1></header><p>This page explains how Fory handles reference tracking for shared and circular references in cross-language serialization.</p> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=overview>Overview<a href=#overview class=hash-link aria-label="Direct link to Overview" title="Direct link to Overview" translate=no></a></h2> |
| <p>Reference tracking enables:</p> |
| <ul> |
| <li class=""><strong>Shared references</strong>: Same object referenced multiple times is serialized once</li> |
| <li class=""><strong>Circular references</strong>: Objects that reference themselves or form cycles</li> |
| <li class=""><strong>Memory efficiency</strong>: No duplicate data for repeated objects</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=enabling-reference-tracking>Enabling Reference Tracking<a href=#enabling-reference-tracking class=hash-link aria-label="Direct link to Enabling Reference Tracking" title="Direct link to Enabling Reference Tracking" translate=no></a></h2> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=java>Java<a href=#java class=hash-link aria-label="Direct link to Java" title="Direct link to Java" translate=no></a></h3> |
| <div class="language-java codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-java codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token class-name">Fory</span><span class="token plain"> fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token class-name">Fory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>builder</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>withXlang</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>withRefTracking</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>build</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=python>Python<a href=#python class=hash-link aria-label="Direct link to Python" title="Direct link to Python" translate=no></a></h3> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token plain">fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Fory</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">xlang</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=go>Go<a href=#go class=hash-link aria-label="Direct link to Go" title="Direct link to Go" translate=no></a></h3> |
| <div class="language-go codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-go codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token plain">fory </span><span class="token operator" style=color:#393A34>:=</span><span class="token plain"> forygo</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>NewFory</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> forygo</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>WithXlang</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> forygo</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>WithTrackRef</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=c>C++<a href=#c class=hash-link aria-label="Direct link to C++" title="Direct link to C++" translate=no></a></h3> |
| <div class="language-cpp codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-cpp codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>auto</span><span class="token plain"> fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> fory</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token plain">serialization</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token class-name">Fory</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token function" style=color:#d73a49>builder</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>xlang</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>track_ref</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>build</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=rust>Rust<a href=#rust class=hash-link aria-label="Direct link to Rust" title="Direct link to Rust" translate=no></a></h3> |
| <div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-rust codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>let</span><span class="token plain"> fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token class-name">Fory</span><span class="token punctuation" style=color:#393A34>::</span><span class="token function" style=color:#d73a49>builder</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>xlang</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>track_ref</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>build</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=scala>Scala<a href=#scala class=hash-link aria-label="Direct link to Scala" title="Direct link to Scala" translate=no></a></h3> |
| <div class="language-scala codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-scala codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> </span><span class="token namespace" style=opacity:0.7>org</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>apache</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>fory</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>scala</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token plain">ForyScala</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>val</span><span class="token plain"> fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> ForyScala</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">builder</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">withXlang</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">withRefTracking</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">build</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=wire-format>Wire Format<a href=#wire-format class=hash-link aria-label="Direct link to Wire Format" title="Direct link to Wire Format" translate=no></a></h2> |
| <p>When reference tracking is enabled, nullable fields write a <strong>ref flag byte</strong> before the value:</p> |
| <div class="language-text codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-text codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token plain">[ref_flag] [value data if not null/ref]</span><br/></div></code></pre></div></div> |
| <p>Where <code>ref_flag</code> is:</p> |
| <table><thead><tr><th>Value<th>Meaning<tbody><tr><td><code>-1</code> (NULL_FLAG)<td>Value is null<tr><td><code>-2</code> (NOT_NULL_VALUE_FLAG)<td>Value is present, first occurrence<tr><td><code>≥0</code><td>Reference ID pointing to previously serialized object</table> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=reference-tracking-vs-nullability>Reference Tracking vs Nullability<a href=#reference-tracking-vs-nullability class=hash-link aria-label="Direct link to Reference Tracking vs Nullability" title="Direct link to Reference Tracking vs Nullability" translate=no></a></h2> |
| <p>These are <strong>independent</strong> concepts:</p> |
| <table><thead><tr><th>Concept<th>Purpose<th>Controlled By<tbody><tr><td><strong>Nullability</strong><td>Whether a field can hold null values<td>Field type (<code>Optional<T></code>) or annotation<tr><td><strong>Reference Tracking</strong><td>Whether duplicate objects are deduplicated<td>Global <code>refTracking</code> option</table> |
| <p>Key behavior:</p> |
| <ul> |
| <li class="">Ref flag bytes are <strong>only written for nullable fields</strong></li> |
| <li class="">Non-nullable fields skip ref flags entirely, even with <code>refTracking=true</code></li> |
| <li class="">Reference deduplication only applies to objects that appear multiple times</li> |
| </ul> |
| <div class="language-java codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-java codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token comment" style=color:#999988;font-style:italic>// Reference tracking enabled, but non-nullable fields still skip ref flags</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token class-name">Fory</span><span class="token plain"> fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token class-name">Fory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>builder</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>withXlang</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>withRefTracking</span><span class="token punctuation" style=color:#393A34>(</span><span class="token boolean" style=color:#36acaa>true</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>build</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=per-field-reference-tracking>Per-Field Reference Tracking<a href=#per-field-reference-tracking class=hash-link aria-label="Direct link to Per-Field Reference Tracking" title="Direct link to Per-Field Reference Tracking" translate=no></a></h2> |
| <p>By default, <strong>most fields do not track references</strong> even when global <code>refTracking=true</code>. Only specific pointer/smart pointer types track references by default.</p> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=default-behavior-by-language>Default Behavior by Language<a href=#default-behavior-by-language class=hash-link aria-label="Direct link to Default Behavior by Language" title="Direct link to Default Behavior by Language" translate=no></a></h3> |
| <table><thead><tr><th>Language<th>Default Ref Tracking<th>Types That Track Refs by Default<tbody><tr><td>Java<td>No<td>None (use annotation to enable)<tr><td>Python<td>No<td>None (use annotation to enable)<tr><td>Go<td>No<td>None (use <code>fory:"ref"</code> to enable)<tr><td>C++<td>Yes<td><code>std::shared_ptr<T></code>, <code>fory::serialization::SharedWeak<T></code><tr><td>Rust<td>No<td><code>Rc<T></code>, <code>Arc<T></code>, <code>Weak<T></code><tr><td>Scala<td>No<td>None (use <code>@Ref</code> to enable)</table> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=customizing-per-field-ref-tracking>Customizing Per-Field Ref Tracking<a href=#customizing-per-field-ref-tracking class=hash-link aria-label="Direct link to Customizing Per-Field Ref Tracking" title="Direct link to Customizing Per-Field Ref Tracking" translate=no></a></h3> |
| <h4 class="anchor anchorTargetStickyNavbar_Vzrq" id=java-ref-annotation>Java: @Ref Annotation<a href=#java-ref-annotation class=hash-link aria-label="Direct link to Java: @Ref Annotation" title="Direct link to Java: @Ref Annotation" translate=no></a></h4> |
| <div class="language-java codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-java codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>public</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Document</span><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Default: no ref tracking</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">String</span><span class="token plain"> title</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Enable ref tracking for this field</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token annotation punctuation" style=color:#393A34>@Ref</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">Author</span><span class="token plain"> author</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Shared across documents, track refs to avoid duplicates</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">List</span><span class="token operator" style=color:#393A34><</span><span class="token annotation punctuation" style=color:#393A34>@Ref</span><span class="token plain"> </span><span class="token class-name">Tag</span><span class="token operator" style=color:#393A34>></span><span class="token plain"> tags</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><br/></div></code></pre></div></div> |
| <h4 class="anchor anchorTargetStickyNavbar_Vzrq" id=c-fory_struct-field-config>C++: FORY_STRUCT Field Config<a href=#c-fory_struct-field-config class=hash-link aria-label="Direct link to C++: FORY_STRUCT Field Config" title="Direct link to C++: FORY_STRUCT Field Config" translate=no></a></h4> |
| <div class="language-cpp codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-cpp codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>struct</span><span class="token plain"> </span><span class="token class-name">Document</span><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> std</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token plain">string title</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// shared_ptr/SharedWeak track refs by default</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> std</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token plain">shared_ptr</span><span class="token operator" style=color:#393A34><</span><span class="token plain">Author</span><span class="token operator" style=color:#393A34>></span><span class="token plain"> author</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> fory</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token plain">serialization</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token plain">SharedWeak</span><span class="token operator" style=color:#393A34><</span><span class="token plain">Data</span><span class="token operator" style=color:#393A34>></span><span class="token plain"> data</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> std</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token plain">shared_ptr</span><span class="token operator" style=color:#393A34><</span><span class="token plain">Tag</span><span class="token operator" style=color:#393A34>></span><span class="token plain"> tag_owner</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token function" style=color:#d73a49>FORY_STRUCT</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">Document</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> title</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> author</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> data</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">tag_owner</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> fory</span><span class="token double-colon punctuation" style=color:#393A34>::</span><span class="token function" style=color:#d73a49>F</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>ref</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><br/></div></code></pre></div></div> |
| <p>To disable reference tracking for C++ entirely, set |
| <code>Fory::builder().xlang(true).track_ref(false).build()</code> on the serializer.</p> |
| <h4 class="anchor anchorTargetStickyNavbar_Vzrq" id=rust-field-attributes>Rust: Field Attributes<a href=#rust-field-attributes class=hash-link aria-label="Direct link to Rust: Field Attributes" title="Direct link to Rust: Field Attributes" translate=no></a></h4> |
| <div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-rust codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>use</span><span class="token plain"> </span><span class="token namespace" style=opacity:0.7>fory</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>::</span><span class="token class-name">ForyStruct</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>use</span><span class="token plain"> </span><span class="token namespace" style=opacity:0.7>std</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>::</span><span class="token namespace" style=opacity:0.7>rc</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>::</span><span class="token class-name">Rc</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token attribute attr-name" style=color:#00a4db>#[derive(ForyStruct)]</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>struct</span><span class="token plain"> </span><span class="token type-definition class-name">Document</span><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> title</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token class-name">String</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Rc/Arc track refs by default</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> author</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token class-name">Rc</span><span class="token operator" style=color:#393A34><</span><span class="token class-name">Author</span><span class="token operator" style=color:#393A34>></span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Explicitly enable ref tracking</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token attribute attr-name" style=color:#00a4db>#[fory(ref = true)]</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> tags</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token class-name">Vec</span><span class="token operator" style=color:#393A34><</span><span class="token class-name">Tag</span><span class="token operator" style=color:#393A34>></span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><br/></div></code></pre></div></div> |
| <h4 class="anchor anchorTargetStickyNavbar_Vzrq" id=scala-ref-annotation>Scala: @Ref Annotation<a href=#scala-ref-annotation class=hash-link aria-label="Direct link to Scala: @Ref Annotation" title="Direct link to Scala: @Ref Annotation" translate=no></a></h4> |
| <p>Scala schema IDL and Scala 3 macro derivation use the same shared JVM <code>@Ref</code> |
| annotation:</p> |
| <div class="language-scala codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-scala codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> </span><span class="token namespace" style=opacity:0.7>org</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>apache</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>fory</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>annotation</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain">ForyField</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ForyStruct</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> Ref</span><span class="token punctuation" style=color:#393A34>}</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> </span><span class="token namespace" style=opacity:0.7>org</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>apache</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>fory</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token namespace" style=opacity:0.7>scala</span><span class="token namespace punctuation" style=opacity:0.7;color:#393A34>.</span><span class="token plain">ForySerializer</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token annotation punctuation" style=color:#393A34>@ForyStruct</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>final</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> Node</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>derives</span><span class="token plain"> ForySerializer </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token annotation punctuation" style=color:#393A34>@ForyField</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">id </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>var</span><span class="token plain"> children</span><span class="token operator" style=color:#393A34>:</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">Node </span><span class="token annotation punctuation" style=color:#393A34>@Ref</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">empty</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token annotation punctuation" style=color:#393A34>@Ref</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token annotation punctuation" style=color:#393A34>@ForyField</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">id </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>var</span><span class="token plain"> parent</span><span class="token operator" style=color:#393A34>:</span><span class="token plain"> Option</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">Node</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> None</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><br/></div></code></pre></div></div> |
| <p>For Scala, top-level field reference tracking is owned by <code>@Ref</code> on the field or |
| constructor parameter. Type-use <code>T @Ref</code> is for nested element/value/payload |
| references, such as <code>List[Node @Ref]</code>.</p> |
| <h4 class="anchor anchorTargetStickyNavbar_Vzrq" id=go-struct-tags>Go: Struct Tags<a href=#go-struct-tags class=hash-link aria-label="Direct link to Go: Struct Tags" title="Direct link to Go: Struct Tags" translate=no></a></h4> |
| <div class="language-go codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-go codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>type</span><span class="token plain"> Document </span><span class="token keyword" style=color:#00009f>struct</span><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> Title </span><span class="token builtin">string</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Enable ref tracking for pointer to struct</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> Author </span><span class="token operator" style=color:#393A34>*</span><span class="token plain">Author </span><span class="token string" style=color:#e3116c>`fory:"ref"`</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Enable ref tracking for slice</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> Tags </span><span class="token punctuation" style=color:#393A34>[</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain">Tag </span><span class="token string" style=color:#e3116c>`fory:"ref"`</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=when-to-enable-per-field-ref-tracking>When to Enable Per-Field Ref Tracking<a href=#when-to-enable-per-field-ref-tracking class=hash-link aria-label="Direct link to When to Enable Per-Field Ref Tracking" title="Direct link to When to Enable Per-Field Ref Tracking" translate=no></a></h3> |
| <p>Enable ref tracking for fields that:</p> |
| <ul> |
| <li class="">May contain the same object instance multiple times</li> |
| <li class="">Are part of circular reference chains</li> |
| <li class="">Hold large objects that might be shared</li> |
| </ul> |
| <p>Disable (or leave default) for fields that:</p> |
| <ul> |
| <li class="">Always contain unique values</li> |
| <li class="">Are primitives or simple value types</li> |
| <li class="">Don't participate in object sharing</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=example-shared-references>Example: Shared References<a href=#example-shared-references class=hash-link aria-label="Direct link to Example: Shared References" title="Direct link to Example: Shared References" translate=no></a></h2> |
| <div class="language-java codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-java codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>public</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Container</span><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">List</span><span class="token generics punctuation" style=color:#393A34><</span><span class="token generics class-name">String</span><span class="token generics punctuation" style=color:#393A34>></span><span class="token plain"> data</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">List</span><span class="token generics punctuation" style=color:#393A34><</span><span class="token generics class-name">String</span><span class="token generics punctuation" style=color:#393A34>></span><span class="token plain"> sameData</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Points to same list</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token class-name">Container</span><span class="token plain"> obj </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>new</span><span class="token plain"> </span><span class="token class-name">Container</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain">obj</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">data </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token class-name">Arrays</span><span class="token punctuation" style=color:#393A34>.</span><span class="token function" style=color:#d73a49>asList</span><span class="token punctuation" style=color:#393A34>(</span><span class="token string" style=color:#e3116c>"a"</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>"b"</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>"c"</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain">obj</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">sameData </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> obj</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">data</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Shared reference</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token comment" style=color:#999988;font-style:italic>// With refTracking=true: data serialized once, sameData stores reference ID</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token comment" style=color:#999988;font-style:italic>// With refTracking=false: data serialized twice (duplicate)</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=example-circular-references>Example: Circular References<a href=#example-circular-references class=hash-link aria-label="Direct link to Example: Circular References" title="Direct link to Example: Circular References" translate=no></a></h2> |
| <div class="language-java codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-java codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>public</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Node</span><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>{</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">String</span><span class="token plain"> value</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token class-name">Node</span><span class="token plain"> next</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token punctuation" style=color:#393A34>}</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token class-name">Node</span><span class="token plain"> a </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>new</span><span class="token plain"> </span><span class="token class-name">Node</span><span class="token punctuation" style=color:#393A34>(</span><span class="token string" style=color:#e3116c>"A"</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token class-name">Node</span><span class="token plain"> b </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token keyword" style=color:#00009f>new</span><span class="token plain"> </span><span class="token class-name">Node</span><span class="token punctuation" style=color:#393A34>(</span><span class="token string" style=color:#e3116c>"B"</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain">a</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">next </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> b</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain">b</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">next </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> a</span><span class="token punctuation" style=color:#393A34>;</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic>// Circular reference</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token comment" style=color:#999988;font-style:italic>// With refTracking=true: works correctly</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token comment" style=color:#999988;font-style:italic>// With refTracking=false: infinite recursion error</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=language-support>Language Support<a href=#language-support class=hash-link aria-label="Direct link to Language Support" title="Direct link to Language Support" translate=no></a></h2> |
| <table><thead><tr><th>Language<th>Shared Refs<th>Circular Refs<tbody><tr><td>Java<td>Yes<td>Yes<tr><td>Python<td>Yes<td>Yes<tr><td>Go<td>Yes<td>Yes<tr><td>C++<td>Yes<td>Yes<tr><td>JavaScript<td>Yes<td>Yes<tr><td>Rust<td>Yes<td>No (ownership rules)</table> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=performance-considerations>Performance Considerations<a href=#performance-considerations class=hash-link aria-label="Direct link to Performance Considerations" title="Direct link to Performance Considerations" translate=no></a></h2> |
| <ul> |
| <li class=""><strong>Overhead</strong>: Reference tracking adds a hash map lookup per object</li> |
| <li class=""><strong>When to enable</strong>: Use when data has shared/circular references</li> |
| <li class=""><strong>When to disable</strong>: Use for simple data structures without sharing</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=see-also>See Also<a href=#see-also class=hash-link aria-label="Direct link to See Also" title="Direct link to See Also" translate=no></a></h2> |
| <ul> |
| <li class=""><a class="" href=/docs/next/guide/xlang/field_nullability>Field Nullability</a> - How nullability affects serialization</li> |
| <li class=""><a class="" href=/docs/next/guide/xlang/serialization>Serialization</a> - Basic cross-language serialization examples</li> |
| <li class=""><a class="" href=/docs/next/specification/xlang_serialization_spec>Xlang Specification</a> - Binary protocol details</li> |
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