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Diffstat (limited to 'libjava/java/lang/Throwable.java')
| -rw-r--r-- | libjava/java/lang/Throwable.java | 563 |
1 files changed, 0 insertions, 563 deletions
diff --git a/libjava/java/lang/Throwable.java b/libjava/java/lang/Throwable.java deleted file mode 100644 index c47a14b..0000000 --- a/libjava/java/lang/Throwable.java +++ /dev/null @@ -1,563 +0,0 @@ -/* java.lang.Throwable -- Root class for all Exceptions and Errors - Copyright (C) 1998, 1999, 2002, 2004, 2005 Free Software Foundation, Inc. - -This file is part of GNU Classpath. - -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. - -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., 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301 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 gnu.classpath.SystemProperties; - -import java.io.PrintStream; -import java.io.PrintWriter; -import java.io.Serializable; - -/** - * 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 updated to 1.4 - */ -public class Throwable implements Serializable -{ - /** - * Compatible with JDK 1.0+. - */ - private static final long serialVersionUID = -3042686055658047285L; - - /** - * The detail message. - * - * @serial specific details about the exception, may be null - */ - private final 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 - */ - 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); - } - - /** - * 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) - { - fillInStackTrace(); - detailMessage = message; - } - - /** - * 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); - this.cause = 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; - } - - /** - * 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() - { - return cause == this ? null : cause; - } - - /** - * 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) - { - 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) - { - s.print(stackTraceString()); - } - - /** - * Prints the exception, the detailed message and the stack trace - * associated with this Throwable to the given <code>PrintWriter</code>. - * The actual output written is implemention specific. Use the result of - * <code>getStackTrace()</code> when more precise information is needed. - * - * <p>This implementation first prints a line with the result of this - * object's <code>toString()</code> method. - * <br> - * Then for all elements given by <code>getStackTrace</code> it prints - * a line containing three spaces, the string "at " and the result of calling - * the <code>toString()</code> method on the <code>StackTraceElement</code> - * object. If <code>getStackTrace()</code> returns an empty array it prints - * a line containing three spaces and the string - * "<<No stacktrace available>>". - * <br> - * Then if <code>getCause()</code> doesn't return null it adds a line - * starting with "Caused by: " and the result of calling - * <code>toString()</code> on the cause. - * <br> - * Then for every cause (of a cause, etc) the stacktrace is printed the - * same as for the top level <code>Throwable</code> except that as soon - * as all the remaining stack frames of the cause are the same as the - * the last stack frames of the throwable that the cause is wrapped in - * then a line starting with three spaces and the string "... X more" is - * printed, where X is the number of remaining stackframes. - * - * @param pw the PrintWriter to write the trace to - * @since 1.1 - */ - public void printStackTrace (PrintWriter pw) - { - pw.print(stackTraceString()); - } - - /* - * We use inner class to avoid a static initializer in this basic class. - */ - private static class StaticData - { - static final String nl = SystemProperties.getProperty("line.separator"); - } - - // Create whole stack trace in a stringbuffer so we don't have to print - // it line by line. This prevents printing multiple stack traces from - // different threads to get mixed up when written to the same PrintWriter. - private String stackTraceString() - { - StringBuffer sb = new StringBuffer(); - - // Main stacktrace - StackTraceElement[] stack = getStackTrace(); - stackTraceStringBuffer(sb, this.toString(), stack, 0); - - // The cause(s) - Throwable cause = getCause(); - while (cause != null) - { - // Cause start first line - sb.append("Caused by: "); - - // Cause stacktrace - StackTraceElement[] parentStack = stack; - stack = cause.getStackTrace(); - if (parentStack == null || parentStack.length == 0) - stackTraceStringBuffer(sb, cause.toString(), stack, 0); - else - { - int equal = 0; // Count how many of the last stack frames are equal - int frame = stack.length-1; - int parentFrame = parentStack.length-1; - while (frame > 0 && parentFrame > 0) - { - if (stack[frame].equals(parentStack[parentFrame])) - { - equal++; - frame--; - parentFrame--; - } - else - break; - } - stackTraceStringBuffer(sb, cause.toString(), stack, equal); - } - cause = cause.getCause(); - } - - return sb.toString(); - } - - // Adds to the given StringBuffer a line containing the name and - // all stacktrace elements minus the last equal ones. - private static void stackTraceStringBuffer(StringBuffer sb, String name, - StackTraceElement[] stack, int equal) - { - String nl = StaticData.nl; - // (finish) first line - sb.append(name); - sb.append(nl); - - // The stacktrace - if (stack == null || stack.length == 0) - { - sb.append(" <<No stacktrace available>>"); - sb.append(nl); - } - else - { - for (int i = 0; i < stack.length-equal; i++) - { - sb.append(" at "); - sb.append(stack[i] == null ? "<<Unknown>>" : stack[i].toString()); - sb.append(nl); - } - if (equal > 0) - { - sb.append(" ..."); - sb.append(equal); - sb.append(" more"); - sb.append(nl); - } - } - } - - /** - * Fill in the stack trace with the current execution stack. - * - * @return this same throwable - * @see #printStackTrace() - */ - public Throwable fillInStackTrace() - { - vmState = VMThrowable.fillInStackTrace(this); - stackTrace = null; // Should be regenerated when used. - - return this; - } - - /** - * 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() - { - if (stackTrace == null) - if (vmState == null) - stackTrace = new StackTraceElement[0]; - else - { - stackTrace = vmState.getStackTrace(this); - vmState = null; // No longer needed - } - - return stackTrace; - } - - /** - * 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. - * <p> - * The contents of the given stacktrace is copied so changes to the - * original array do not change the stack trace elements of this - * throwable. - * - * @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) - { - int i = stackTrace.length; - StackTraceElement[] st = new StackTraceElement[i]; - - while (--i >= 0) - { - st[i] = stackTrace[i]; - if (st[i] == null) - throw new NullPointerException("Element " + i + " null"); - } - - this.stackTrace = st; - } - - /** - * VM state when fillInStackTrace was called. - * Used by getStackTrace() to get an array of StackTraceElements. - * Cleared when no longer needed. - */ - private transient VMThrowable vmState; -} |