jdk/src/share/classes/java/lang/StackTraceElement.java
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@@ -1,7 +1,7 @@
/*
- * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
@@ -23,10 +23,12 @@
* questions.
*/
package java.lang;
+import java.util.Objects;
+
/**
* An element in a stack trace, as returned by {@link
* Throwable#getStackTrace()}. Each element represents a single stack frame.
* All stack frames except for the one at the top of the stack represent
* a method invocation. The frame at the top of the stack represents the
@@ -51,55 +53,50 @@
* @param declaringClass the fully qualified name of the class containing
* the execution point represented by the stack trace element
* @param methodName the name of the method containing the execution point
* represented by the stack trace element
* @param fileName the name of the file containing the execution point
- * represented by the stack trace element, or <tt>null</tt> if
+ * represented by the stack trace element, or {@code null} if
* this information is unavailable
* @param lineNumber the line number of the source line containing the
* execution point represented by this stack trace element, or
* a negative number if this information is unavailable. A value
* of -2 indicates that the method containing the execution point
* is a native method
- * @throws NullPointerException if <tt>declaringClass</tt> or
- * <tt>methodName</tt> is null
+ * @throws NullPointerException if {@code declaringClass} or
+ * {@code methodName} is null
* @since 1.5
*/
public StackTraceElement(String declaringClass, String methodName,
String fileName, int lineNumber) {
- if (declaringClass == null)
- throw new NullPointerException("Declaring class is null");
- if (methodName == null)
- throw new NullPointerException("Method name is null");
-
- this.declaringClass = declaringClass;
- this.methodName = methodName;
+ this.declaringClass = Objects.nonNull(declaringClass, "Declaring class is null");
+ this.methodName = Objects.nonNull(methodName, "Method name is null");
this.fileName = fileName;
this.lineNumber = lineNumber;
}
/**
* Returns the name of the source file containing the execution point
* represented by this stack trace element. Generally, this corresponds
- * to the <tt>SourceFile</tt> attribute of the relevant <tt>class</tt>
+ * to the {@code SourceFile} attribute of the relevant {@code class}
* file (as per <i>The Java Virtual Machine Specification</i>, Section
* 4.7.7). In some systems, the name may refer to some source code unit
* other than a file, such as an entry in source repository.
*
* @return the name of the file containing the execution point
- * represented by this stack trace element, or <tt>null</tt> if
+ * represented by this stack trace element, or {@code null} if
* this information is unavailable.
*/
public String getFileName() {
return fileName;
}
/**
* Returns the line number of the source line containing the execution
* point represented by this stack trace element. Generally, this is
- * derived from the <tt>LineNumberTable</tt> attribute of the relevant
- * <tt>class</tt> file (as per <i>The Java Virtual Machine
+ * derived from the {@code LineNumberTable} attribute of the relevant
+ * {@code class} file (as per <i>The Java Virtual Machine
* Specification</i>, Section 4.7.8).
*
* @return the line number of the source line containing the execution
* point represented by this stack trace element, or a negative
* number if this information is unavailable.
@@ -110,23 +107,23 @@
/**
* Returns the fully qualified name of the class containing the
* execution point represented by this stack trace element.
*
- * @return the fully qualified name of the <tt>Class</tt> containing
+ * @return the fully qualified name of the {@code Class} containing
* the execution point represented by this stack trace element.
*/
public String getClassName() {
return declaringClass;
}
/**
* Returns the name of the method containing the execution point
* represented by this stack trace element. If the execution point is
* contained in an instance or class initializer, this method will return
- * the appropriate <i>special method name</i>, <tt><init></tt> or
- * <tt><clinit></tt>, as per Section 3.9 of <i>The Java Virtual
+ * the appropriate <i>special method name</i>, {@code <init>} or
+ * {@code <clinit>}, as per Section 3.9 of <i>The Java Virtual
* Machine Specification</i>.
*
* @return the name of the method containing the execution point
* represented by this stack trace element.
*/
@@ -136,11 +133,11 @@
/**
* Returns true if the method containing the execution point
* represented by this stack trace element is a native method.
*
- * @return <tt>true</tt> if the method containing the execution point
+ * @return {@code true} if the method containing the execution point
* represented by this stack trace element is a native method.
*/
public boolean isNativeMethod() {
return lineNumber == -2;
}
@@ -149,25 +146,25 @@
* Returns a string representation of this stack trace element. The
* format of this string depends on the implementation, but the following
* examples may be regarded as typical:
* <ul>
* <li>
- * <tt>"MyClass.mash(MyClass.java:9)"</tt> - Here, <tt>"MyClass"</tt>
+ * {@code "MyClass.mash(MyClass.java:9)"} - Here, {@code "MyClass"}
* is the <i>fully-qualified name</i> of the class containing the
* execution point represented by this stack trace element,
- * <tt>"mash"</tt> is the name of the method containing the execution
- * point, <tt>"MyClass.java"</tt> is the source file containing the
- * execution point, and <tt>"9"</tt> is the line number of the source
+ * {@code "mash"} is the name of the method containing the execution
+ * point, {@code "MyClass.java"} is the source file containing the
+ * execution point, and {@code "9"} is the line number of the source
* line containing the execution point.
* <li>
- * <tt>"MyClass.mash(MyClass.java)"</tt> - As above, but the line
+ * {@code "MyClass.mash(MyClass.java)"} - As above, but the line
* number is unavailable.
* <li>
- * <tt>"MyClass.mash(Unknown Source)"</tt> - As above, but neither
+ * {@code "MyClass.mash(Unknown Source)"} - As above, but neither
* the file name nor the line number are available.
* <li>
- * <tt>"MyClass.mash(Native Method)"</tt> - As above, but neither
+ * {@code "MyClass.mash(Native Method)"} - As above, but neither
* the file name nor the line number are available, and the method
* containing the execution point is known to be a native method.
* </ul>
* @see Throwable#printStackTrace()
*/
@@ -179,51 +176,45 @@
(fileName != null ? "("+fileName+")" : "(Unknown Source)")));
}
/**
* Returns true if the specified object is another
- * <tt>StackTraceElement</tt> instance representing the same execution
- * point as this instance. Two stack trace elements <tt>a</tt> and
- * <tt>b</tt> are equal if and only if:
+ * {@code StackTraceElement} instance representing the same execution
+ * point as this instance. Two stack trace elements {@code a} and
+ * {@code b} are equal if and only if:
* <pre>
* equals(a.getFileName(), b.getFileName()) &&
* a.getLineNumber() == b.getLineNumber()) &&
* equals(a.getClassName(), b.getClassName()) &&
* equals(a.getMethodName(), b.getMethodName())
* </pre>
- * where <tt>equals</tt> is defined as:
- * <pre>
- * static boolean equals(Object a, Object b) {
- * return a==b || (a != null && a.equals(b));
- * }
- * </pre>
+ * where {@code equals} has the semantics of {@link
+ * java.util.Objects#equals(Object, Object) Objects.equals}.
*
* @param obj the object to be compared with this stack trace element.
* @return true if the specified object is another
- * <tt>StackTraceElement</tt> instance representing the same
+ * {@code StackTraceElement} instance representing the same
* execution point as this instance.
*/
public boolean equals(Object obj) {
if (obj==this)
return true;
if (!(obj instanceof StackTraceElement))
return false;
StackTraceElement e = (StackTraceElement)obj;
- return e.declaringClass.equals(declaringClass) && e.lineNumber == lineNumber
- && eq(methodName, e.methodName) && eq(fileName, e.fileName);
- }
-
- private static boolean eq(Object a, Object b) {
- return a==b || (a != null && a.equals(b));
+ return e.declaringClass.equals(declaringClass) &&
+ e.lineNumber == lineNumber &&
+ Objects.equals(methodName, e.methodName) &&
+ Objects.equals(fileName, e.fileName);
}
/**
* Returns a hash code value for this stack trace element.
*/
public int hashCode() {
int result = 31*declaringClass.hashCode() + methodName.hashCode();
- result = 31*result + (fileName == null ? 0 : fileName.hashCode());
+ result = 31*result + Objects.hashCode(fileName);
result = 31*result + lineNumber;
return result;
}
private static final long serialVersionUID = 6992337162326171013L;