/*
 * TransformerException.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP 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 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAXP 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 this program; 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
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */
package javax.xml.transform;

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

/**
 * An exception occurred during the transformation process.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public class TransformerException
  extends Exception
{

  private SourceLocator  locator;
  private Throwable  cause;

  /**
   * Constructor with a detail message.
   */
  public TransformerException(String msg)
  {
    this(msg, null, null);
  }

  /**
   * Constructor with an underlying cause.
   */
  public TransformerException(Throwable cause)
  {
    this(cause.getMessage(), null, cause);
  }

  /**
   * Constructor with a detail message and underlying cause.
   */
  public TransformerException(String msg, Throwable cause)
  {
    this(msg, null, cause);
  }

  /**
   * Constructor with a detail message and locator.
   */
  public TransformerException(String msg, SourceLocator locator)
  {
    this(msg, locator, null);
  }

  /**
   * Constructor with detail message, locator and underlying cause.
   */
  public TransformerException(String msg, SourceLocator locator, 
                              Throwable cause)
  {
    super(msg);
    this.locator = locator;
    if (cause != null)
      {
        initCause(cause);
        this.cause = cause;
      }
  }

  /**
   * Returns a locator indicating where the error occurred.
   */
  public SourceLocator getLocator()
  {
    return locator;
  }

  /**
   * Sets the locator indicating where the error occurred.
   */
  public void setLocator(SourceLocator location)
  {
    locator = location;
  }

  /**
   * Returns the underlying cause of this exception.
   */
  public Throwable getException()
  {
    return cause;
  }

  /**
   * Returns the underlying cause of this exception.
   */
  public Throwable getCause()
  {
    return cause;
  }

  /**
   * Initializes the root cause of this exception.
   * This method may be called only once, and will be called by the
   * constructor if a non-null cause is specified.
   * Really phenomenally poor API design.
   * @param cause the underlying cause
   * @exception IllegalArgumentException if this exception is passed as the
   * argument
   * @exception IllegalStateException if a cause has already been
   * initialized
   */
  public Throwable initCause(Throwable cause)
  {
    if (this.cause != null)
      {
        throw new IllegalStateException();
      }
    if (cause == this)
      {
        throw new IllegalArgumentException();
      }
    this.cause = cause;
    return this;
  }

  /**
   * Returns the exception message with location information appended.
   */
  public String getMessageAndLocation()
  {
    return (locator == null) ? getMessage() :
      getMessage() + ": " + getLocationAsString();
  }

  /**
   * Returns the location information as a string.
   */
  public String getLocationAsString()
  {
    if (locator == null)
      {
        return null;
      }
    String publicId = locator.getPublicId();
    String systemId = locator.getSystemId();
    int lineNumber = locator.getLineNumber();
    int columnNumber = locator.getColumnNumber();
    StringBuffer buffer = new StringBuffer ();
    if (publicId != null)
      {
        buffer.append ("publicId=");
        buffer.append (publicId);
      }
    if (systemId != null)
      {
        if (buffer.length() > 0)
          {
            buffer.append(' ');
          }
        buffer.append ("systemId=");
        buffer.append (systemId);
      }
    if (lineNumber != -1)
      {
        if (buffer.length() > 0)
          {
            buffer.append(' ');
          }
        buffer.append ("lineNumber=");
        buffer.append (lineNumber);
      }
    if (columnNumber != -1)
      {
        if (buffer.length() > 0)
          {
            buffer.append(' ');
          }
        buffer.append ("columnNumber=");
        buffer.append (columnNumber);
      }
    return buffer.toString();
  }

  public void printStackTrace()
  {
    printStackTrace(System.out);
  }

  public void printStackTrace(PrintStream s)
  {
    super.printStackTrace(s);
    if (cause != null)
      {
        s.print("caused by ");
        cause.printStackTrace(s);
      }
  }

  public void printStackTrace(PrintWriter s)
  {
    super.printStackTrace(s);
    if (cause != null)
      {
        s.print("caused by ");
        cause.printStackTrace(s);
      }
  }

}
