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| <li>Summary: </li> |
| <li>Nested | </li> |
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| <div class="sub-title"><span class="package-label-in-type">Package</span> <a href="package-summary.html">org.apache.logging.log4j.util</a></div> |
| <h1 title="Class StackLocator" class="title">Class StackLocator</h1> |
| </div> |
| <div class="inheritance" title="Inheritance Tree"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html" title="class or interface in java.lang" class="external-link">java.lang.Object</a> |
| <div class="inheritance">org.apache.logging.log4j.util.StackLocator</div> |
| </div> |
| <section class="class-description" id="class-description"> |
| <hr> |
| <div class="type-signature"><span class="annotations"><a href="InternalApi.html" title="annotation in org.apache.logging.log4j.util">@InternalApi</a> |
| </span><span class="modifiers">public final class </span><span class="element-name type-name-label">StackLocator</span> |
| <span class="extends-implements">extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></span></div> |
| <div class="block"><em>Consider this class private.</em> Provides various methods to determine the caller class. |
| |
| <h2>Background</h2> |
| <p> |
| This method, available only in the Oracle/Sun/OpenJDK implementations of the Java Virtual Machine, is a much more |
| efficient mechanism for determining the <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link"><code>Class</code></a> of the caller of a particular method. When it is not available, |
| a <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/SecurityManager.html" title="class or interface in java.lang" class="external-link"><code>SecurityManager</code></a> is the second-best option. When this is also not possible, the <code>StackTraceElement[]</code> |
| returned by <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Throwable.html#getStackTrace--" title="class or interface in java.lang" class="external-link"><code>Throwable.getStackTrace()</code></a> must be used, and its <code>String</code> class name converted to a |
| <code>Class</code> using the slow <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html#forName-java.lang.String-" title="class or interface in java.lang" class="external-link"><code>Class.forName(java.lang.String)</code></a> (which can add an extra microsecond or more for each invocation |
| depending on the runtime ClassLoader hierarchy). |
| </p> |
| <p> |
| During Java 8 development, the <code>sun.reflect.Reflection.getCallerClass(int)</code> was removed from OpenJDK, and this |
| change was back-ported to Java 7 in version 1.7.0_25 which changed the behavior of the call and caused it to be off |
| by one stack frame. This turned out to be beneficial for the survival of this API as the change broke hundreds of |
| libraries and frameworks relying on the API which brought much more attention to the intended API removal. |
| </p> |
| <p> |
| After much community backlash, the JDK team agreed to restore <code>getCallerClass(int)</code> and keep its existing |
| behavior for the rest of Java 7. However, the method is deprecated in Java 8, and current Java 9 development has not |
| addressed this API. Therefore, the functionality of this class cannot be relied upon for all future versions of Java. |
| It does, however, work just fine in Sun JDK 1.6, OpenJDK 1.6, Oracle/OpenJDK 1.7, and Oracle/OpenJDK 1.8. Other Java |
| environments may fall back to using <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Throwable.html#getStackTrace--" title="class or interface in java.lang" class="external-link"><code>Throwable.getStackTrace()</code></a> which is significantly slower due to |
| examination of every virtual frame of execution. |
| </p></div> |
| </section> |
| <section class="summary"> |
| <ul class="summary-list"> |
| <!-- ========== METHOD SUMMARY =========== --> |
| <li> |
| <section class="method-summary" id="method-summary"> |
| <h2>Method Summary</h2> |
| <div id="method-summary-table"> |
| <div class="table-tabs" role="tablist" aria-orientation="horizontal"><button id="method-summary-table-tab0" role="tab" aria-selected="true" aria-controls="method-summary-table.tabpanel" tabindex="0" onkeydown="switchTab(event)" onclick="show('method-summary-table', 'method-summary-table', 3)" class="active-table-tab">All Methods</button><button id="method-summary-table-tab1" role="tab" aria-selected="false" aria-controls="method-summary-table.tabpanel" tabindex="-1" onkeydown="switchTab(event)" onclick="show('method-summary-table', 'method-summary-table-tab1', 3)" class="table-tab">Static Methods</button><button id="method-summary-table-tab2" role="tab" aria-selected="false" aria-controls="method-summary-table.tabpanel" tabindex="-1" onkeydown="switchTab(event)" onclick="show('method-summary-table', 'method-summary-table-tab2', 3)" class="table-tab">Instance Methods</button><button id="method-summary-table-tab4" role="tab" aria-selected="false" aria-controls="method-summary-table.tabpanel" tabindex="-1" onkeydown="switchTab(event)" onclick="show('method-summary-table', 'method-summary-table-tab4', 3)" class="table-tab">Concrete Methods</button></div> |
| <div id="method-summary-table.tabpanel" role="tabpanel"> |
| <div class="summary-table three-column-summary" aria-labelledby="method-summary-table-tab0"> |
| <div class="table-header col-first">Modifier and Type</div> |
| <div class="table-header col-second">Method</div> |
| <div class="table-header col-last">Description</div> |
| <div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/StackTraceElement.html" title="class or interface in java.lang" class="external-link">StackTraceElement</a></code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#calcLocation(java.lang.String)" class="member-name-link">calcLocation</a><wbr>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html" title="class or interface in java.lang" class="external-link">String</a> fqcnOfLogger)</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getCallerClass(int)" class="member-name-link">getCallerClass</a><wbr>(int depth)</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> |
| <div class="block">Gets the Class of the method that called <em>this</em> method at the location up the call stack by the given stack |
| frame depth.</div> |
| </div> |
| <div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getCallerClass(java.lang.Class)" class="member-name-link">getCallerClass</a><wbr>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?> anchor)</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getCallerClass(java.lang.Class,java.util.function.Predicate)" class="member-name-link">getCallerClass</a><wbr>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?> sentinelClass, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/function/Predicate.html" title="class or interface in java.util.function" class="external-link">Predicate</a><<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?>> callerPredicate)</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| <div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getCallerClass(java.lang.String,java.lang.String)" class="member-name-link">getCallerClass</a><wbr>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html" title="class or interface in java.lang" class="external-link">String</a> fqcn, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html" title="class or interface in java.lang" class="external-link">String</a> pkg)</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/util/Deque.html" title="class or interface in java.util" class="external-link">Deque</a><<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?>></code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getCurrentStackTrace()" class="member-name-link">getCurrentStackTrace</a>()</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| <div class="col-first even-row-color method-summary-table method-summary-table-tab1 method-summary-table-tab4"><code>static <a href="StackLocator.html" title="class in org.apache.logging.log4j.util">StackLocator</a></code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab1 method-summary-table-tab4"><code><a href="#getInstance()" class="member-name-link">getInstance</a>()</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab1 method-summary-table-tab4"> |
| <div class="block">Gets the singleton instance.</div> |
| </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/StackTraceElement.html" title="class or interface in java.lang" class="external-link">StackTraceElement</a></code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getStackTraceElement(int)" class="member-name-link">getStackTraceElement</a><wbr>(int depth)</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| </div> |
| </div> |
| </div> |
| <div class="inherited-list"> |
| <h3 id="methods-inherited-from-class-java.lang.Object">Methods inherited from class java.lang.<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></h3> |
| <code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#clone--" title="class or interface in java.lang" class="external-link">clone</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#equals-java.lang.Object-" title="class or interface in java.lang" class="external-link">equals</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#finalize--" title="class or interface in java.lang" class="external-link">finalize</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#getClass--" title="class or interface in java.lang" class="external-link">getClass</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#hashCode--" title="class or interface in java.lang" class="external-link">hashCode</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#notify--" title="class or interface in java.lang" class="external-link">notify</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#notifyAll--" title="class or interface in java.lang" class="external-link">notifyAll</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#toString--" title="class or interface in java.lang" class="external-link">toString</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--" title="class or interface in java.lang" class="external-link">wait</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-" title="class or interface in java.lang" class="external-link">wait</a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-" title="class or interface in java.lang" class="external-link">wait</a></code></div> |
| </section> |
| </li> |
| </ul> |
| </section> |
| <section class="details"> |
| <ul class="details-list"> |
| <!-- ============ METHOD DETAIL ========== --> |
| <li> |
| <section class="method-details" id="method-detail"> |
| <h2>Method Details</h2> |
| <ul class="member-list"> |
| <li> |
| <section class="detail" id="getInstance()"> |
| <h3>getInstance</h3> |
| <div class="member-signature"><span class="modifiers">public static</span> <span class="return-type"><a href="StackLocator.html" title="class in org.apache.logging.log4j.util">StackLocator</a></span> <span class="element-name">getInstance</span>()</div> |
| <div class="block">Gets the singleton instance.</div> |
| <dl class="notes"> |
| <dt>Returns:</dt> |
| <dd>the singleton instance.</dd> |
| </dl> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getCallerClass(java.lang.Class,java.util.function.Predicate)"> |
| <h3>getCallerClass</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></span> <span class="element-name">getCallerClass</span><wbr><span class="parameters">(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?> sentinelClass, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/function/Predicate.html" title="class or interface in java.util.function" class="external-link">Predicate</a><<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?>> callerPredicate)</span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getCallerClass(int)"> |
| <h3>getCallerClass</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></span> <span class="element-name">getCallerClass</span><wbr><span class="parameters">(int depth)</span></div> |
| <div class="block">Gets the Class of the method that called <em>this</em> method at the location up the call stack by the given stack |
| frame depth. |
| <p> |
| This method returns <code>null</code> if: |
| </p> |
| <ul> |
| <li><code>sun.reflect.Reflection.getCallerClass(int)</code> is not present.</li> |
| <li>An exception is caught calling <code>sun.reflect.Reflection.getCallerClass(int)</code>.</li> |
| </ul></div> |
| <dl class="notes"> |
| <dt>Parameters:</dt> |
| <dd><code>depth</code> - The stack frame count to walk.</dd> |
| <dt>Returns:</dt> |
| <dd>A class or null.</dd> |
| <dt>Throws:</dt> |
| <dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/IndexOutOfBoundsException.html" title="class or interface in java.lang" class="external-link">IndexOutOfBoundsException</a></code> - if depth is negative.</dd> |
| </dl> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getCallerClass(java.lang.String,java.lang.String)"> |
| <h3>getCallerClass</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></span> <span class="element-name">getCallerClass</span><wbr><span class="parameters">(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html" title="class or interface in java.lang" class="external-link">String</a> fqcn, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html" title="class or interface in java.lang" class="external-link">String</a> pkg)</span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getCallerClass(java.lang.Class)"> |
| <h3>getCallerClass</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?></span> <span class="element-name">getCallerClass</span><wbr><span class="parameters">(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?> anchor)</span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getCurrentStackTrace()"> |
| <h3>getCurrentStackTrace</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/util/Deque.html" title="class or interface in java.util" class="external-link">Deque</a><<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html" title="class or interface in java.lang" class="external-link">Class</a><?>></span> <span class="element-name">getCurrentStackTrace</span>()</div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="calcLocation(java.lang.String)"> |
| <h3>calcLocation</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/StackTraceElement.html" title="class or interface in java.lang" class="external-link">StackTraceElement</a></span> <span class="element-name">calcLocation</span><wbr><span class="parameters">(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html" title="class or interface in java.lang" class="external-link">String</a> fqcnOfLogger)</span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getStackTraceElement(int)"> |
| <h3>getStackTraceElement</h3> |
| <div class="member-signature"><span class="modifiers">public</span> <span class="return-type"><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/StackTraceElement.html" title="class or interface in java.lang" class="external-link">StackTraceElement</a></span> <span class="element-name">getStackTraceElement</span><wbr><span class="parameters">(int depth)</span></div> |
| </section> |
| </li> |
| </ul> |
| </section> |
| </li> |
| </ul> |
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| </div> |
| </body> |
| </html> |
