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XPathException (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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JavaTM 2 Platform
Standard Ed. 5.0
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javax.xml.xpath
Class XPathException

java.lang.Object
  extended by java.lang.Throwable
      extended by java.lang.Exception
          extended by javax.xml.xpath.XPathException
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
XPathExpressionException, XPathFactoryConfigurationException
public class XPathException
extends Exception

XPathException represents a generic XPath exception.

Since:
1.5
See Also:
Serialized Form

Constructor Summary
XPathException(String message)
          Constructs a new XPathException with the specified detail message.
XPathException(Throwable cause)
          Constructs a new XPathException with the specified cause.
 
Method Summary
 Throwable getCause()
          Returns the cause of this throwable or null if the cause is nonexistent or unknown.
 void printStackTrace()
          Prints this throwable and its backtrace to the standard error stream.
 void printStackTrace(PrintStream s)
          Prints this throwable and its backtrace to the specified print stream.
 void printStackTrace(PrintWriter s)
          Prints this throwable and its backtrace to the specified print writer.
 
Methods inherited from class java.lang.Throwable
fillInStackTrace, getLocalizedMessage, getMessage, getStackTrace, initCause, setStackTrace, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

XPathException

public XPathException(String message)

Constructs a new XPathException with the specified detail message.

The cause is not initialized.

If message is null, then a NullPointerException is thrown.

Parameters:
message - The detail message.

XPathException

public XPathException(Throwable cause)

Constructs a new XPathException with the specified cause.

If cause is null, then a NullPointerException is thrown.

Parameters:
cause - The cause.
Throws:
NullPointerException - if cause is null.
Method Detail

getCause

public Throwable getCause()
Description copied from class: Throwable
Returns the cause of this throwable or null if the cause is nonexistent or unknown. (The cause is the throwable that caused this throwable to get thrown.)

This implementation returns the cause that was supplied via one of the constructors requiring a Throwable, or that was set after creation with the Throwable.initCause(Throwable) method. While it is typically unnecessary to override this method, a subclass can override it to return a cause set by some other means. This is appropriate for a "legacy chained throwable" that predates the addition of chained exceptions to Throwable. Note that it is not necessary to override any of the PrintStackTrace methods, all of which invoke the getCause method to determine the cause of a throwable.

Overrides:
getCause in class Throwable
Returns:
the cause of this throwable or null if the cause is nonexistent or unknown.

printStackTrace

public void printStackTrace(PrintStream s)
Description copied from class: Throwable
Prints this throwable and its backtrace to the specified print stream.

Overrides:
printStackTrace in class Throwable
Parameters:
s - PrintStream to use for output

printStackTrace

public void printStackTrace()
Description copied from class: Throwable
Prints this throwable and its backtrace to the standard error stream. This method prints a stack trace for this Throwable object on the error output stream that is the value of the field System.err. The first line of output contains the result of the Throwable.toString() method for this object. Remaining lines represent data previously recorded by the method Throwable.fillInStackTrace(). The format of this information depends on the implementation, but the following example may be regarded as typical: 
 java.lang.NullPointerException
         at MyClass.mash(MyClass.java:9)
         at MyClass.crunch(MyClass.java:6)
         at MyClass.main(MyClass.java:3)
This example was produced by running the program: 
 class MyClass {
     public static void main(String[] args) {
         crunch(null);
     }
     static void crunch(int[] a) {
         mash(a);
     }
     static void mash(int[] b) {
         System.out.println(b[0]);
     }
 }
The backtrace for a throwable with an initialized, non-null cause should generally include the backtrace for the cause. The format of this information depends on the implementation, but the following example may be regarded as typical: 
 HighLevelException: MidLevelException: LowLevelException
         at Junk.a(Junk.java:13)
         at Junk.main(Junk.java:4)
 Caused by: MidLevelException: LowLevelException
         at Junk.c(Junk.java:23)
         at Junk.b(Junk.java:17)
         at Junk.a(Junk.java:11)
         ... 1 more
 Caused by: LowLevelException
         at Junk.e(Junk.java:30)
         at Junk.d(Junk.java:27)
         at Junk.c(Junk.java:21)
         ... 3 more
Note the presence of lines containing the characters "...". These lines indicate that the remainder of the stack trace for this exception matches the indicated number of frames from the bottom of the stack trace of the exception that was caused by this exception (the "enclosing" exception). This shorthand can greatly reduce the length of the output in the common case where a wrapped exception is thrown from same method as the "causative exception" is caught. The above example was produced by running the program: 
 public class Junk {
     public static void main(String args[]) { 
         try {
             a();
         } catch(HighLevelException e) {
             e.printStackTrace();
         }
     }
     static void a() throws HighLevelException {
         try {
             b();
         } catch(MidLevelException e) {
             throw new HighLevelException(e);
         }
     }
     static void b() throws MidLevelException {
         c();
     }   
     static void c() throws MidLevelException {
         try {
             d();
         } catch(LowLevelException e) {
             throw new MidLevelException(e);
         }
     }
     static void d() throws LowLevelException { 
        e();
     }
     static void e() throws LowLevelException {
         throw new LowLevelException();
     }
 }

 class HighLevelException extends Exception {
     HighLevelException(Throwable cause) { super(cause); }
 }

 class MidLevelException extends Exception {
     MidLevelException(Throwable cause)  { super(cause); }
 }
 
 class LowLevelException extends Exception {
 }

Overrides:
printStackTrace in class Throwable

printStackTrace

public void printStackTrace(PrintWriter s)
Description copied from class: Throwable
Prints this throwable and its backtrace to the specified print writer.

Overrides:
printStackTrace in class Throwable
Parameters:
s - PrintWriter to use for output
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JavaTM 2 Platform
Standard Ed. 5.0
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.