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<a name="1" href="#1">1</a> <em class="jxr_comment">/*</em>
<a name="2" href="#2">2</a> <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one</em>
<a name="3" href="#3">3</a> <em class="jxr_comment"> * or more contributor license agreements. See the NOTICE file</em>
<a name="4" href="#4">4</a> <em class="jxr_comment"> * distributed with this work for additional information</em>
<a name="5" href="#5">5</a> <em class="jxr_comment"> * regarding copyright ownership. The ASF licenses this file</em>
<a name="6" href="#6">6</a> <em class="jxr_comment"> * to you under the Apache License, Version 2.0 (the</em>
<a name="7" href="#7">7</a> <em class="jxr_comment"> * "License"); you may not use this file except in compliance</em>
<a name="8" href="#8">8</a> <em class="jxr_comment"> * with the License. You may obtain a copy of the License at</em>
<a name="9" href="#9">9</a> <em class="jxr_comment"> *</em>
<a name="10" href="#10">10</a> <em class="jxr_comment"> * <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a name="11" href="#11">11</a> <em class="jxr_comment"> *</em>
<a name="12" href="#12">12</a> <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing,</em>
<a name="13" href="#13">13</a> <em class="jxr_comment"> * software distributed under the License is distributed on an</em>
<a name="14" href="#14">14</a> <em class="jxr_comment"> * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY</em>
<a name="15" href="#15">15</a> <em class="jxr_comment"> * KIND, either express or implied. See the License for the</em>
<a name="16" href="#16">16</a> <em class="jxr_comment"> * specific language governing permissions and limitations</em>
<a name="17" href="#17">17</a> <em class="jxr_comment"> * under the License.</em>
<a name="18" href="#18">18</a> <em class="jxr_comment"> */</em>
<a name="19" href="#19">19</a> <strong class="jxr_keyword">package</strong> org.apache.shiro.subject.support;
<a name="20" href="#20">20</a>
<a name="21" href="#21">21</a> <strong class="jxr_keyword">import</strong> org.apache.shiro.subject.Subject;
<a name="22" href="#22">22</a> <strong class="jxr_keyword">import</strong> org.apache.shiro.util.ThreadState;
<a name="23" href="#23">23</a>
<a name="24" href="#24">24</a> <strong class="jxr_keyword">import</strong> java.util.concurrent.Callable;
<a name="25" href="#25">25</a>
<a name="26" href="#26">26</a> <em class="jxr_javadoccomment">/**</em>
<a name="27" href="#27">27</a> <em class="jxr_javadoccomment"> * A {@code SubjectCallable} associates a {@link Subject Subject} with a target/delegate</em>
<a name="28" href="#28">28</a> <em class="jxr_javadoccomment"> * {@link Callable Callable} to ensure proper {@code Subject} thread-state management when the {@code Callable} executes.</em>
<a name="29" href="#29">29</a> <em class="jxr_javadoccomment"> * This ensures that any calls to {@code SecurityUtils.}{@link org.apache.shiro.SecurityUtils#getSubject() getSubject()}</em>
<a name="30" href="#30">30</a> <em class="jxr_javadoccomment"> * during the target {@code Callable}'s execution still work correctly even if the {@code Callable} executes on a</em>
<a name="31" href="#31">31</a> <em class="jxr_javadoccomment"> * different thread than the one that created it. This allows {@code Subject} access during asynchronous operations.</em>
<a name="32" href="#32">32</a> <em class="jxr_javadoccomment"> * &lt;p/&gt;</em>
<a name="33" href="#33">33</a> <em class="jxr_javadoccomment"> * When instances of this class execute (typically via a {@link java.util.concurrent.ExecutorService ExecutorService}),</em>
<a name="34" href="#34">34</a> <em class="jxr_javadoccomment"> * the following occurs:</em>
<a name="35" href="#35">35</a> <em class="jxr_javadoccomment"> * &lt;ol&gt;</em>
<a name="36" href="#36">36</a> <em class="jxr_javadoccomment"> * &lt;li&gt;The specified Subject any of its associated thread state is first bound to the thread that executes the</em>
<a name="37" href="#37">37</a> <em class="jxr_javadoccomment"> * {@code Callable}.&lt;/li&gt;</em>
<a name="38" href="#38">38</a> <em class="jxr_javadoccomment"> * &lt;li&gt;The delegate/target {@code Callable} is {@link java.util.concurrent.Callable#call() executed}&lt;/li&gt;</em>
<a name="39" href="#39">39</a> <em class="jxr_javadoccomment"> * &lt;li&gt;The previous thread state that might have existed before the {@code Subject} was bound is fully restored&lt;/li&gt;</em>
<a name="40" href="#40">40</a> <em class="jxr_javadoccomment"> * &lt;/ol&gt;</em>
<a name="41" href="#41">41</a> <em class="jxr_javadoccomment"> * &lt;p/&gt;</em>
<a name="42" href="#42">42</a> <em class="jxr_javadoccomment"> * This behavior ensures that the thread that executes this {@code Callable}, which is often a different thread than</em>
<a name="43" href="#43">43</a> <em class="jxr_javadoccomment"> * the one that created the instance, retains a {@code Subject} to support {@code SecurityUtils.getSubject()}</em>
<a name="44" href="#44">44</a> <em class="jxr_javadoccomment"> * invocations. It also guarantees that the running thread remains 'clean' in any thread-pooled environments.</em>
<a name="45" href="#45">45</a> <em class="jxr_javadoccomment"> *</em>
<a name="46" href="#46">46</a> <em class="jxr_javadoccomment"> * &lt;h3&gt;Usage&lt;/h3&gt;</em>
<a name="47" href="#47">47</a> <em class="jxr_javadoccomment"> *</em>
<a name="48" href="#48">48</a> <em class="jxr_javadoccomment"> * This is typically considered a support class and is not often directly referenced. Most people prefer to use</em>
<a name="49" href="#49">49</a> <em class="jxr_javadoccomment"> * the {@code Subject.}{@link Subject#associateWith(Callable) associateWith} method, which will automatically return</em>
<a name="50" href="#50">50</a> <em class="jxr_javadoccomment"> * an instance of this class.</em>
<a name="51" href="#51">51</a> <em class="jxr_javadoccomment"> * &lt;p/&gt;</em>
<a name="52" href="#52">52</a> <em class="jxr_javadoccomment"> * An even more convenient alternative is to use a</em>
<a name="53" href="#53">53</a> <em class="jxr_javadoccomment"> * {@link org.apache.shiro.concurrent.SubjectAwareExecutorService SubjectAwareExecutorService}, which</em>
<a name="54" href="#54">54</a> <em class="jxr_javadoccomment"> * transparently uses instances of this class.</em>
<a name="55" href="#55">55</a> <em class="jxr_javadoccomment"> *</em>
<a name="56" href="#56">56</a> <em class="jxr_javadoccomment"> * @see Subject#associateWith(Callable)</em>
<a name="57" href="#57">57</a> <em class="jxr_javadoccomment"> * @see org.apache.shiro.concurrent.SubjectAwareExecutorService SubjectAwareExecutorService</em>
<a name="58" href="#58">58</a> <em class="jxr_javadoccomment"> * @since 1.0</em>
<a name="59" href="#59">59</a> <em class="jxr_javadoccomment"> */</em>
<a name="60" href="#60">60</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">class</strong> SubjectCallable&lt;V&gt; implements Callable&lt;V&gt; {
<a name="61" href="#61">61</a>
<a name="62" href="#62">62</a> <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">final</strong> <a href="../../../../../org/apache/shiro/util/ThreadState.html">ThreadState</a> threadState;
<a name="63" href="#63">63</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> Callable&lt;V&gt; callable;
<a name="64" href="#64">64</a>
<a name="65" href="#65">65</a> <strong class="jxr_keyword">public</strong> <a href="../../../../../org/apache/shiro/subject/support/SubjectCallable.html">SubjectCallable</a>(<a href="../../../../../org/apache/shiro/subject/Subject.html">Subject</a> subject, Callable&lt;V&gt; delegate) {
<a name="66" href="#66">66</a> <strong class="jxr_keyword">this</strong>(<strong class="jxr_keyword">new</strong> <a href="../../../../../org/apache/shiro/subject/support/SubjectThreadState.html">SubjectThreadState</a>(subject), delegate);
<a name="67" href="#67">67</a> }
<a name="68" href="#68">68</a>
<a name="69" href="#69">69</a> <strong class="jxr_keyword">protected</strong> <a href="../../../../../org/apache/shiro/subject/support/SubjectCallable.html">SubjectCallable</a>(<a href="../../../../../org/apache/shiro/util/ThreadState.html">ThreadState</a> threadState, Callable&lt;V&gt; delegate) {
<a name="70" href="#70">70</a> <strong class="jxr_keyword">if</strong> (threadState == <strong class="jxr_keyword">null</strong>) {
<a name="71" href="#71">71</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(<span class="jxr_string">"ThreadState argument cannot be null."</span>);
<a name="72" href="#72">72</a> }
<a name="73" href="#73">73</a> <strong class="jxr_keyword">this</strong>.threadState = threadState;
<a name="74" href="#74">74</a> <strong class="jxr_keyword">if</strong> (delegate == <strong class="jxr_keyword">null</strong>) {
<a name="75" href="#75">75</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(<span class="jxr_string">"Callable delegate instance cannot be null."</span>);
<a name="76" href="#76">76</a> }
<a name="77" href="#77">77</a> <strong class="jxr_keyword">this</strong>.callable = delegate;
<a name="78" href="#78">78</a> }
<a name="79" href="#79">79</a>
<a name="80" href="#80">80</a> <strong class="jxr_keyword">public</strong> V call() <strong class="jxr_keyword">throws</strong> Exception {
<a name="81" href="#81">81</a> <strong class="jxr_keyword">try</strong> {
<a name="82" href="#82">82</a> threadState.bind();
<a name="83" href="#83">83</a> <strong class="jxr_keyword">return</strong> doCall(<strong class="jxr_keyword">this</strong>.callable);
<a name="84" href="#84">84</a> } <strong class="jxr_keyword">finally</strong> {
<a name="85" href="#85">85</a> threadState.restore();
<a name="86" href="#86">86</a> }
<a name="87" href="#87">87</a> }
<a name="88" href="#88">88</a>
<a name="89" href="#89">89</a> <strong class="jxr_keyword">protected</strong> V doCall(Callable&lt;V&gt; target) <strong class="jxr_keyword">throws</strong> Exception {
<a name="90" href="#90">90</a> <strong class="jxr_keyword">return</strong> target.call();
<a name="91" href="#91">91</a> }
<a name="92" href="#92">92</a> }
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