/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */
/*
 * $Id: DTMException.java 468653 2006-10-28 07:07:05Z minchau $
 */
package org.apache.xml.dtm;


import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.xml.transform.SourceLocator;

import org.apache.xml.res.XMLErrorResources;
import org.apache.xml.res.XMLMessages;


This class specifies an exceptional condition that occured
in the DTM module.
/**
 * This class specifies an exceptional condition that occured
 * in the DTM module.
 */
public class DTMException extends RuntimeException {
    static final long serialVersionUID = -775576419181334734L;

    
Field locator specifies where the error occured.
 @serial /** Field locator specifies where the error occured.
     *  @serial */
    SourceLocator locator;

    
Method getLocator retrieves an instance of a SourceLocator
object that specifies where an error occured.
Returns:
A SourceLocator object, or null if none was specified./**
     * Method getLocator retrieves an instance of a SourceLocator
     * object that specifies where an error occured.
     *
     * @return A SourceLocator object, or null if none was specified.
     */
    public SourceLocator getLocator() {
        return locator;
    }

    
Method setLocator sets an instance of a SourceLocator
object that specifies where an error occured.
Params:
location – A SourceLocator object, or null to clear the location./**
     * Method setLocator sets an instance of a SourceLocator
     * object that specifies where an error occured.
     *
     * @param location A SourceLocator object, or null to clear the location.
     */
    public void setLocator(SourceLocator location) {
        locator = location;
    }

    
Field containedException specifies a wrapped exception.  May be null.
 @serial /** Field containedException specifies a wrapped exception.  May be null.
     *  @serial */
    Throwable containedException;

    
This method retrieves an exception that this exception wraps.
See Also:
getCause
Returns:
An Throwable object, or null./**
     * This method retrieves an exception that this exception wraps.
     *
     * @return An Throwable object, or null.
     * @see #getCause
     */
    public Throwable getException() {
        return containedException;
    }

    
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.)
/**
     * Returns the cause of this throwable or <code>null</code> if the
     * cause is nonexistent or unknown.  (The cause is the throwable that
     * caused this throwable to get thrown.)
     */
    public Throwable getCause() {

        return ((containedException == this)
                ? null
                : containedException);
    }

    
Initializes the cause of this throwable to the specified value.
(The cause is the throwable that caused this throwable to get thrown.)
This method can be called at most once. It is generally called from within the constructor, or immediately after creating the throwable. If this throwable was created with DTMException(Throwable) or DTMException(String, Throwable), this method cannot be called even once. 
Params:
cause – the cause (which is saved for later retrieval by the getCause() method). (A null value is
        permitted, and indicates that the cause is nonexistent or
        unknown.)
Throws:
IllegalArgumentException – if cause is this
        throwable.  (A throwable cannot
        be its own cause.)
IllegalStateException – if this throwable was created with DTMException(Throwable) or DTMException(String, Throwable), or this method has already been called on this throwable.
Returns:
 a reference to this Throwable instance./**
     * Initializes the <i>cause</i> of this throwable to the specified value.
     * (The cause is the throwable that caused this throwable to get thrown.)
     *
     * <p>This method can be called at most once.  It is generally called from
     * within the constructor, or immediately after creating the
     * throwable.  If this throwable was created
     * with {@link #DTMException(Throwable)} or
     * {@link #DTMException(String,Throwable)}, this method cannot be called
     * even once.
     *
     * @param  cause the cause (which is saved for later retrieval by the
     *         {@link #getCause()} method).  (A <tt>null</tt> value is
     *         permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @return  a reference to this <code>Throwable</code> instance.
     * @throws IllegalArgumentException if <code>cause</code> is this
     *         throwable.  (A throwable cannot
     *         be its own cause.)
     * @throws IllegalStateException if this throwable was
     *         created with {@link #DTMException(Throwable)} or
     *         {@link #DTMException(String,Throwable)}, or this method has already
     *         been called on this throwable.
     */
    public synchronized Throwable initCause(Throwable cause) {

        if ((this.containedException == null) && (cause != null)) {
            throw new IllegalStateException(XMLMessages.createXMLMessage(XMLErrorResources.ER_CANNOT_OVERWRITE_CAUSE, null)); //"Can't overwrite cause");
        }

        if (cause == this) {
            throw new IllegalArgumentException(
                XMLMessages.createXMLMessage(XMLErrorResources.ER_SELF_CAUSATION_NOT_PERMITTED, null)); //"Self-causation not permitted");
        }

        this.containedException = cause;

        return this;
    }

    
Create a new DTMException.
Params:
message – The error or warning message./**
     * Create a new DTMException.
     *
     * @param message The error or warning message.
     */
    public DTMException(String message) {

        super(message);

        this.containedException = null;
        this.locator            = null;
    }

    
Create a new DTMException wrapping an existing exception.
Params:
e – The exception to be wrapped./**
     * Create a new DTMException wrapping an existing exception.
     *
     * @param e The exception to be wrapped.
     */
    public DTMException(Throwable e) {

        super(e.getMessage());

        this.containedException = e;
        this.locator            = null;
    }

    
Wrap an existing exception in a DTMException.
This is used for throwing processor exceptions before
the processing has started.
Params:
message – The error or warning message, or null to
               use the message from the embedded exception.
e – Any exception/**
     * Wrap an existing exception in a DTMException.
     *
     * <p>This is used for throwing processor exceptions before
     * the processing has started.</p>
     *
     * @param message The error or warning message, or null to
     *                use the message from the embedded exception.
     * @param e Any exception
     */
    public DTMException(String message, Throwable e) {

        super(((message == null) || (message.length() == 0))
              ? e.getMessage()
              : message);

        this.containedException = e;
        this.locator            = null;
    }

    
Create a new DTMException from a message and a Locator.
This constructor is especially useful when an application is
creating its own exception from within a DocumentHandler
callback.
Params:
message – The error or warning message.
locator – The locator object for the error or warning./**
     * Create a new DTMException from a message and a Locator.
     *
     * <p>This constructor is especially useful when an application is
     * creating its own exception from within a DocumentHandler
     * callback.</p>
     *
     * @param message The error or warning message.
     * @param locator The locator object for the error or warning.
     */
    public DTMException(String message, SourceLocator locator) {

        super(message);

        this.containedException = null;
        this.locator            = locator;
    }

    
Wrap an existing exception in a DTMException.
Params:
message – The error or warning message, or null to
               use the message from the embedded exception.
locator – The locator object for the error or warning.
e – Any exception/**
     * Wrap an existing exception in a DTMException.
     *
     * @param message The error or warning message, or null to
     *                use the message from the embedded exception.
     * @param locator The locator object for the error or warning.
     * @param e Any exception
     */
    public DTMException(String message, SourceLocator locator,
                                Throwable e) {

        super(message);

        this.containedException = e;
        this.locator            = locator;
    }

    
Get the error message with location information
appended.
/**
     * Get the error message with location information
     * appended.
     */
    public String getMessageAndLocation() {

        StringBuffer sbuffer = new StringBuffer();
        String       message = super.getMessage();

        if (null != message) {
            sbuffer.append(message);
        }

        if (null != locator) {
            String systemID = locator.getSystemId();
            int    line     = locator.getLineNumber();
            int    column   = locator.getColumnNumber();

            if (null != systemID) {
                sbuffer.append("; SystemID: ");
                sbuffer.append(systemID);
            }

            if (0 != line) {
                sbuffer.append("; Line#: ");
                sbuffer.append(line);
            }

            if (0 != column) {
                sbuffer.append("; Column#: ");
                sbuffer.append(column);
            }
        }

        return sbuffer.toString();
    }

    
Get the location information as a string.
Returns:
A string with location info, or null
if there is no location information./**
     * Get the location information as a string.
     *
     * @return A string with location info, or null
     * if there is no location information.
     */
    public String getLocationAsString() {

        if (null != locator) {
            StringBuffer sbuffer  = new StringBuffer();
            String       systemID = locator.getSystemId();
            int          line     = locator.getLineNumber();
            int          column   = locator.getColumnNumber();

            if (null != systemID) {
                sbuffer.append("; SystemID: ");
                sbuffer.append(systemID);
            }

            if (0 != line) {
                sbuffer.append("; Line#: ");
                sbuffer.append(line);
            }

            if (0 != column) {
                sbuffer.append("; Column#: ");
                sbuffer.append(column);
            }

            return sbuffer.toString();
        } else {
            return null;
        }
    }

    
Print the the trace of methods from where the error
originated.  This will trace all nested exception
objects, as well as this object.
/**
     * Print the the trace of methods from where the error
     * originated.  This will trace all nested exception
     * objects, as well as this object.
     */
    public void printStackTrace() {
        printStackTrace(new java.io.PrintWriter(System.err, true));
    }

    
Print the the trace of methods from where the error
originated.  This will trace all nested exception
objects, as well as this object.
Params:
s – The stream where the dump will be sent to./**
     * Print the the trace of methods from where the error
     * originated.  This will trace all nested exception
     * objects, as well as this object.
     * @param s The stream where the dump will be sent to.
     */
    public void printStackTrace(java.io.PrintStream s) {
        printStackTrace(new java.io.PrintWriter(s));
    }

    
Print the the trace of methods from where the error
originated.  This will trace all nested exception
objects, as well as this object.
Params:
s – The writer where the dump will be sent to./**
     * Print the the trace of methods from where the error
     * originated.  This will trace all nested exception
     * objects, as well as this object.
     * @param s The writer where the dump will be sent to.
     */
    public void printStackTrace(java.io.PrintWriter s) {

        if (s == null) {
            s = new java.io.PrintWriter(System.err, true);
        }

        try {
            String locInfo = getLocationAsString();

            if (null != locInfo) {
                s.println(locInfo);
            }

            super.printStackTrace(s);
        } catch (Throwable e) {}

        boolean isJdk14OrHigher = false;
        try {
            Throwable.class.getMethod("getCause",null);
            isJdk14OrHigher = true;
        } catch (NoSuchMethodException nsme) {
            // do nothing
        }        

        // The printStackTrace method of the Throwable class in jdk 1.4 
        // and higher will include the cause when printing the backtrace.
        // The following code is only required when using jdk 1.3 or lower                
        if (!isJdk14OrHigher) {
            Throwable exception = getException();
    
            for (int i = 0; (i < 10) && (null != exception); i++) {
                s.println("---------");
    
                try {
                    if (exception instanceof DTMException) {
                        String locInfo =
                            ((DTMException) exception)
                                .getLocationAsString();
    
                        if (null != locInfo) {
                            s.println(locInfo);
                        }
                    }
    
                    exception.printStackTrace(s);
                } catch (Throwable e) {
                    s.println("Could not print stack trace...");
                }
    
                try {
                    Method meth =
                        ((Object) exception).getClass().getMethod("getException",
                            null);
    
                    if (null != meth) {
                        Throwable prev = exception;
    
                        exception = (Throwable) meth.invoke(exception, null);
    
                        if (prev == exception) {
                            break;
                        }
                    } else {
                        exception = null;
                    }
                } catch (InvocationTargetException ite) {
                    exception = null;
                } catch (IllegalAccessException iae) {
                    exception = null;
                } catch (NoSuchMethodException nsme) {
                    exception = null;
                }
            }
        }
    }
}