java.lang
Class StackTraceElement

java.lang.Object
  java.lang.StackTraceElement

All Implemented Interfaces:

Serializable

public final class StackTraceElement

extends Object

implements Serializable

An element in a stack trace, as returned by 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 the execution point at which the stack trace was generated. Typically, this is the point at which the throwable corresponding to the stack trace was created.

Since:

1.4

Author:

Josh Bloch

See Also:

Serialized Form

Field Summary

private String	declaringClass
private String	fileName
private int	lineNumber
private String	methodName
private static long	serialVersionUID

Constructor Summary

private

StackTraceElement() Prevent inappropriate instantiation.

Method Summary

private static boolean	eq(Object a, Object b)
boolean	equals(Object obj) Returns true if the specified object is another StackTraceElement instance representing the same execution point as this instance.
String	getClassName() Returns the fully qualified name of the class containing the execution point represented by this stack trace element.
String	getFileName() Returns the name of the source file containing the execution point represented by this stack trace element.
int	getLineNumber() Returns the line number of the source line containing the execution point represented by this stack trace element.
String	getMethodName() Returns the name of the method containing the execution point represented by this stack trace element.
int	hashCode() Returns a hash code value for this stack trace element.
boolean	isNativeMethod() Returns true if the method containing the execution point represented by this stack trace element is a native method.
String	toString() Returns a string representation of this stack trace element.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

declaringClass

private String declaringClass

methodName

private String methodName

fileName

private String fileName

lineNumber

private int lineNumber

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

StackTraceElement

private StackTraceElement()

Prevent inappropriate instantiation. Only the VM creates these. It creates them "magically" without invoking this constructor.

Method Detail

getFileName

public String getFileName()

Returns the name of the source file containing the execution point represented by this stack trace element. Generally, this corresponds to the SourceFile attribute of the relevant class file (as per The Java Virtual Machine Specification, 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.

Returns:

the name of the file containing the execution point represented by this stack trace element, or null if this information is unavailable.

getLineNumber

public int getLineNumber()

Returns the line number of the source line containing the execution point represented by this stack trace element. Generally, this is derived from the LineNumberTable attribute of the relevant class file (as per The Java Virtual Machine Specification, Section 4.7.8).

Returns:

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.

getClassName

public String getClassName()

Returns the fully qualified name of the class containing the execution point represented by this stack trace element.

Returns:

the fully qualified name of the Class containing the execution point represented by this stack trace element.

getMethodName

public String getMethodName()

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 special method name, <init> or <clinit>, as per Section 3.9 of The Java Virtual Machine Specification.

Returns:

the name of the method containing the execution point represented by this stack trace element.

isNativeMethod

public boolean isNativeMethod()

Returns true if the method containing the execution point represented by this stack trace element is a native method.

Returns:

true if the method containing the execution point represented by this stack trace element is a native method.

toString

public String toString()

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:

• "MyClass.mash(MyClass.java:9)" - Here, "MyClass" is the fully-qualified name of the class containing the execution point represented by this stack trace element, "mash" is the name of the method containing the execution point, "MyClass.java" is the source file containing the execution point, and "9" is the line number of the source line containing the execution point.
• "MyClass.mash(MyClass.java)" - As above, but the line number is unavailable.
• "MyClass.mash(Unknown Source)" - As above, but neither the file name nor the line number are available.
• "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.

Overrides:

toString in class Object

Returns:

a string representation of the object.

See Also:

Throwable.printStackTrace()

equals

public boolean equals(Object obj)

Returns true if the specified object is another StackTraceElement instance representing the same execution point as this instance. Two stack trace elements a and b are equal if and only if:

     equals(a.getFileName(), b.getFileName()) &&
     a.getLineNumber() == b.getLineNumber()) &&
     equals(a.getClassName(), b.getClassName()) &&
     equals(a.getMethodName(), b.getMethodName())
 

where equals is defined as:

     static boolean equals(Object a, Object b) {
         return a==b || (a != null && a.equals(b));
     }
 

Overrides:

equals in class Object

Parameters:

obj - the object to be compared with this stack trace element.

Returns:

true if the specified object is another StackTraceElement instance representing the same execution point as this instance.

See Also:

Object.hashCode(), Hashtable

eq

private static boolean eq(Object a,
                          Object b)

hashCode

public int hashCode()

Returns a hash code value for this stack trace element.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable