Merge JDK 1.4 exception chaining support from classpath.

	* java/lang/Throwable.java: Merge 1.4 support from classpath.
	(stackTraceBytes): Rename from stackTrace.
	* java/lang/Exception.java: Merge from classpath.
	* java/lang/StackTraceElement: New file from classpath.
	* gcj/javaprims.h: Rebuild CNI namespace declarations.
	* Makefile.am: Add StackTraceElement.
	* Makefile.in: Rebuilt.

From-SVN: r53836

1 files changed, 388 insertions, 38 deletions

diff --git a/libjava/java/lang/Throwable.java b/libjava/java/lang/Throwable.java
index 5c330fe..d5488b8 100644
--- a/libjava/java/lang/Throwable.java
+++ b/libjava/java/lang/Throwable.java
@@ -1,21 +1,50 @@
-// Throwable.java - Superclass for all exceptions.
+/* java.lang.Throwable -- Reference implementation of root class for
+   all Exceptions and Errors
+   Copyright (C) 1998, 1999, 2002 Free Software Foundation, Inc.
 
-/* Copyright (C) 1998, 1999  Free Software Foundation
+This file is part of GNU Classpath.
 
-   This file is part of libgcj.
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
 
-This software is copyrighted work licensed under the terms of the
-Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
-details.  */
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
 
 package java.lang;
-import java.io.PrintStream;
-import java.io.PrintWriter;
+
 import java.io.Serializable;
-import java.io.OutputStreamWriter;
-import java.io.OutputStream;
-import java.io.FilterOutputStream;
+import java.io.PrintWriter;
+import java.io.PrintStream;
+import java.io.ObjectOutputStream;
+import java.io.ObjectInputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 
 /**
  * @author Tom Tromey <tromey@cygnus.com>
@@ -98,38 +127,341 @@ class CPlusPlusDemangler extends OutputStream
   }    
 }
 
+/**
+ * Throwable is the superclass of all exceptions that can be raised.
+ *
+ * <p>There are two special cases: {@link Error} and {@link RuntimeException}:
+ * these two classes (and their subclasses) are considered unchecked
+ * exceptions, and are either frequent enough or catastrophic enough that you
+ * do not need to declare them in <code>throws</code> clauses.  Everything
+ * else is a checked exception, and is ususally a subclass of
+ * {@link Exception}; these exceptions have to be handled or declared.
+ *
+ * <p>Instances of this class are usually created with knowledge of the
+ * execution context, so that you can get a stack trace of the problem spot
+ * in the code.  Also, since JDK 1.4, Throwables participate in "exception
+ * chaining."  This means that one exception can be caused by another, and
+ * preserve the information of the original.
+ *
+ * <p>One reason this is useful is to wrap exceptions to conform to an
+ * interface.  For example, it would be bad design to require all levels
+ * of a program interface to be aware of the low-level exceptions thrown
+ * at one level of abstraction. Another example is wrapping a checked
+ * exception in an unchecked one, to communicate that failure occured
+ * while still obeying the method throws clause of a superclass.
+ *
+ * <p>A cause is assigned in one of two ways; but can only be assigned once
+ * in the lifetime of the Throwable.  There are new constructors added to
+ * several classes in the exception hierarchy that directly initialize the
+ * cause, or you can use the <code>initCause</code> method. This second
+ * method is especially useful if the superclass has not been retrofitted
+ * with new constructors:<br>
+ * <pre>
+ * try
+ *   {
+ *     lowLevelOp();
+ *   }
+ * catch (LowLevelException lle)
+ *   {
+ *     throw (HighLevelException) new HighLevelException().initCause(lle);
+ *   }
+ * </pre>
+ * Notice the cast in the above example; without it, your method would need
+ * a throws clase that declared Throwable, defeating the purpose of chainig
+ * your exceptions.
+ *
+ * <p>By convention, exception classes have two constructors: one with no
+ * arguments, and one that takes a String for a detail message.  Further,
+ * classes which are likely to be used in an exception chain also provide
+ * a constructor that takes a Throwable, with or without a detail message
+ * string.
+ *
+ * <p>Another 1.4 feature is the StackTrace, a means of reflection that
+ * allows the program to inspect the context of the exception, and which is
+ * serialized, so that remote procedure calls can correctly pass exceptions.
+ *
+ * @author Brian Jones
+ * @author John Keiser
+ * @author Mark Wielaard
+ * @author Tom Tromey
+ * @author Eric Blake <ebb9@email.byu.edu>
+ * @since 1.0
+ * @status still missing 1.4 functionality
+ */
 public class Throwable implements Serializable
 {
-  public native Throwable fillInStackTrace ();
+  /**
+   * Compatible with JDK 1.0+.
+   */
+  private static final long serialVersionUID = -3042686055658047285L;
+
+  /**
+   * The detail message.
+   *
+   * @serial specific details about the exception, may be null
+   */
+  private String detailMessage;
+
+  /**
+   * The cause of the throwable, including null for an unknown or non-chained
+   * cause. This may only be set once; so the field is set to
+   * <code>this</code> until initialized.
+   *
+   * @serial the cause, or null if unknown, or this if not yet set
+   * @since 1.4
+   */
+  private Throwable cause = this;
+
+  /**
+   * The stack trace, in a serialized form.
+   *
+   * @serial the elements of the stack trace; this is non-null, and has
+   *         no null entries
+   * @since 1.4
+   */
+  // XXX Don't initialize this, once fillInStackTrace() does it.
+  private StackTraceElement[] stackTrace = {};
+
+  /**
+   * Instantiate this Throwable with an empty message. The cause remains
+   * uninitialized.  {@link #fillInStackTrace()} will be called to set
+   * up the stack trace.
+   */
+  public Throwable()
+  {
+    this((String) null);
+  }
 
-  public String getLocalizedMessage ()
+  /**
+   * Instantiate this Throwable with the given message. The cause remains
+   * uninitialized.  {@link #fillInStackTrace()} will be called to set
+   * up the stack trace.
+   *
+   * @param message the message to associate with the Throwable
+   */
+  public Throwable(String message)
   {
-    return getMessage ();
+    fillInStackTrace();
+    detailMessage = message;  
   }
 
-  public String getMessage ()
+  /**
+   * Instantiate this Throwable with the given message and cause. Note that
+   * the message is unrelated to the message of the cause.
+   * {@link #fillInStackTrace()} will be called to set up the stack trace.
+   *
+   * @param message the message to associate with the Throwable
+   * @param cause the cause, may be null
+   * @since 1.4
+   */
+  public Throwable(String message, Throwable cause)
+  {
+    this(message);
+    initCause(cause);
+  }
+
+  /**
+   * Instantiate this Throwable with the given cause. The message is then
+   * built as <code>cause == null ? null : cause.toString()</code>.
+   * {@link #fillInStackTrace()} will be called to set up the stack trace.
+   *
+   * @param cause the cause, may be null
+   * @since 1.4
+   */
+  public Throwable(Throwable cause)
+  {
+    this(cause == null ? null : cause.toString(), cause);
+  }
+
+  /**
+   * Get the message associated with this Throwable.
+   *
+   * @return the error message associated with this Throwable, may be null
+   */
+  public String getMessage()
   {
     return detailMessage;
   }
 
-  public void printStackTrace ()
+  /**
+   * Get a localized version of this Throwable's error message.
+   * This method must be overridden in a subclass of Throwable
+   * to actually produce locale-specific methods.  The Throwable
+   * implementation just returns getMessage().
+   *
+   * @return a localized version of this error message
+   * @see #getMessage()
+   * @since 1.1
+   */
+  public String getLocalizedMessage()
+  {
+    return getMessage();
+  }
+
+  /**
+   * Returns the cause of this exception, or null if the cause is not known
+   * or non-existant. This cause is initialized by the new constructors,
+   * or by calling initCause.
+   *
+   * @return the cause of this Throwable
+   * @since 1.4
+   */
+  public Throwable getCause()
   {
-    printStackTrace (System.err);
+    return cause == this ? null : cause;
   }
 
-  public void printStackTrace (PrintStream ps)
+  /**
+   * Initialize the cause of this Throwable.  This may only be called once
+   * during the object lifetime, including implicitly by chaining
+   * constructors.
+   *
+   * @param cause the cause of this Throwable, may be null
+   * @return this
+   * @throws IllegalArgumentException if cause is this (a Throwable can't be
+   *         its own cause!)
+   * @throws IllegalStateException if the cause has already been set
+   * @since 1.4
+   */
+  public Throwable initCause(Throwable cause)
   {
-    PrintWriter writer = new PrintWriter (ps);
-    printStackTrace (writer);
+    if (cause == this)
+      throw new IllegalArgumentException();
+    if (this.cause != this)
+      throw new IllegalStateException();
+    this.cause = cause;
+    return this;
   }
 
+  /**
+   * Get a human-readable representation of this Throwable. The detail message
+   * is retrieved by getLocalizedMessage().  Then, with a null detail
+   * message, this string is simply the object's class name; otherwise
+   * the string is <code>getClass().getName() + ": " + message</code>.
+   *
+   * @return a human-readable String represting this Throwable
+   */
+  public String toString()
+  {
+    String msg = getLocalizedMessage();
+    return getClass().getName() + (msg == null ? "" : ": " + msg);
+  }
+
+  /**
+   * Print a stack trace to the standard error stream. This stream is the
+   * current contents of <code>System.err</code>. The first line of output
+   * is the result of {@link #toString()}, and the remaining lines represent
+   * the data created by {@link #fillInStackTrace()}. While the format is
+   * unspecified, this implementation uses the suggested format, demonstrated
+   * by this example:<br>
+   * <pre>
+   * 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
+   * {
+   * }
+   * </pre>
+   * <p>
+   * <pre>
+   *  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
+   * </pre>
+   */
+  public void printStackTrace()
+  {
+    printStackTrace(System.err);
+  }
+
+  /**
+   * Print a stack trace to the specified PrintStream. See
+   * {@link #printStackTrace()} for the sample format.
+   *
+   * @param s the PrintStream to write the trace to
+   */
+  public void printStackTrace(PrintStream s)
+  {
+    printStackTrace(new PrintWriter(s));
+  }
+
+  /**
+   * Print a stack trace to the specified PrintWriter. See
+   * {@link #printStackTrace()} for the sample format.
+   *
+   * @param w the PrintWriter to write the trace to
+   * @since 1.1
+   */
   public void printStackTrace (PrintWriter wr)
   {
     try
       {
 	CPlusPlusDemangler cPlusPlusFilter = new CPlusPlusDemangler (wr);
 	PrintWriter writer = new PrintWriter (cPlusPlusFilter);
-	printRawStackTrace (writer);	
+	printRawStackTrace (writer);
 	writer.close ();
 	if (cPlusPlusFilter.written == 0) // The demangler has failed...
 	  printRawStackTrace (wr);
@@ -140,32 +472,50 @@ public class Throwable implements Serializable
       }
   }
 
-  public Throwable ()
-  {
-    detailMessage = null;
-    fillInStackTrace ();
-  }
+  /**
+   * Fill in the stack trace with the current execution stack.
+   *
+   * @return this same throwable
+   * @see #printStackTrace()
+   */
+  public native Throwable fillInStackTrace();
 
-  public Throwable (String message)
+  /**
+   * Provides access to the information printed in {@link #printStackTrace()}.
+   * The array is non-null, with no null entries, although the virtual
+   * machine is allowed to skip stack frames.  If the array is not 0-length,
+   * then slot 0 holds the information on the stack frame where the Throwable
+   * was created (or at least where <code>fillInStackTrace()</code> was
+   * called).
+   *
+   * @return an array of stack trace information, as available from the VM
+   * @since 1.4
+   */
+  public StackTraceElement[] getStackTrace()
   {
-    detailMessage = message;
-    fillInStackTrace ();
+    return stackTrace;
   }
 
-  public String toString ()
+  /**
+   * Change the stack trace manually. This method is designed for remote
+   * procedure calls, which intend to alter the stack trace before or after
+   * serialization according to the context of the remote call.
+   *
+   * @param stackTrace the new trace to use
+   * @throws NullPointerException if stackTrace is null or has null elements
+   * @since 1.4
+   */
+  public void setStackTrace(StackTraceElement[] stackTrace)
   {
-    return ((detailMessage == null)
-	    ? getClass().getName()
-	    : getClass().getName() + ": " + getMessage ());
+    for (int i = stackTrace.length; --i >= 0; )
+      if (stackTrace[i] == null)
+        throw new NullPointerException();
+    this.stackTrace = stackTrace;
   }
 
   private native final void printRawStackTrace (PrintWriter wr);
   
-  // Name of this field comes from serialization spec.
-  private String detailMessage;
-
   // Setting this flag to false prevents fillInStackTrace() from running.
   static boolean trace_enabled = true;
-  private transient byte stackTrace[];
-  private static final long serialVersionUID = -3042686055658047285L;
+  private transient byte stackTraceBytes[];
 }