BuildException.java

/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.jmeld.tools.ant;

import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * Signals an error condition during a build
 *
 */
public class BuildException
    extends RuntimeException
{
  /** Exception that might have caused this one. */
  private Throwable cause;

  /**
   * Constructs a build exception with no descriptive information.
   */
  public BuildException()
  {
    super();
  }

  /**
   * Constructs an exception with the given descriptive message.
   *
   * @param message A description of or information about the exception.
   *            Should not be <code>null</code>.
   */
  public BuildException(String message)
  {
    super(message);
  }

  /**
   * Constructs an exception with the given message and exception as
   * a root cause.
   *
   * @param message A description of or information about the exception.
   *            Should not be <code>null</code> unless a cause is specified.
   * @param cause The exception that might have caused this one.
   *              May be <code>null</code>.
   */
  public BuildException(String message, Throwable cause)
  {
    super(message);
    this.cause = cause;
  }

  /**
   * Constructs an exception with the given exception as a root cause.
   *
   * @param cause The exception that might have caused this one.
   *              Should not be <code>null</code>.
   */
  public BuildException(Throwable cause)
  {
    super(cause.toString());
    this.cause = cause;
  }

  /**
   * Returns the nested exception, if any.
   *
   * @return the nested exception, or <code>null</code> if no
   *         exception is associated with this one
   */
  public Throwable getException()
  {
    return cause;
  }

  /**
   * Returns the nested exception, if any.
   *
   * @return the nested exception, or <code>null</code> if no
   *         exception is associated with this one
   */
  public Throwable getCause()
  {
    return getException();
  }

  /**
   * Returns the error message.
   *
   * @return the error message
   */
  public String toString()
  {
    return getMessage();
  }

  /**
   * Prints the stack trace for this exception and any
   * nested exception to <code>System.err</code>.
   */
  public void printStackTrace()
  {
    printStackTrace(System.err);
  }

  /**
   * Prints the stack trace of this exception and any nested
   * exception to the specified PrintStream.
   *
   * @param ps The PrintStream to print the stack trace to.
   *           Must not be <code>null</code>.
   */
  public void printStackTrace(PrintStream ps)
  {
    synchronized (ps)
    {
      super.printStackTrace(ps);
      if (cause != null)
      {
        ps.println("--- Nested Exception ---");
        cause.printStackTrace(ps);
      }
    }
  }

  /**
   * Prints the stack trace of this exception and any nested
   * exception to the specified PrintWriter.
   *
   * @param pw The PrintWriter to print the stack trace to.
   *           Must not be <code>null</code>.
   */
  public void printStackTrace(PrintWriter pw)
  {
    synchronized (pw)
    {
      super.printStackTrace(pw);
      if (cause != null)
      {
        pw.println("--- Nested Exception ---");
        cause.printStackTrace(pw);
      }
    }
  }
}