/*
* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
*
* This software is open source.
* See the bottom of this file for the licence.
*/
package org.dom4j.io;
import java.util.
ArrayList;
import java.util.
HashMap;
import org.dom4j.
Element;
import org.dom4j.
ElementHandler;
import org.dom4j.
ElementPath;
/**
* <p>
* <code>DispatchHandler</code> implements the <code>ElementHandler</code>
* interface and provides a means to register multiple
* <code>ElementHandler</code> instances to be used by an event based
* processor. This is a special <code>ElementHandler</code> in that it's
* <b>onStart </b> and <b>onEnd </b> implementation methods are called for every
* element encountered during the parse. It then delegates to other
* <code>ElementHandler</code> instances registered with it to process the
* elements encountered.
* </p>
*
* @author <a href="mailto:dwhite@equipecom.com">Dave White </a>
* @version $Revision: 1.11 $
*/
class
DispatchHandler implements
ElementHandler {
/** Whether the parser is at the root element or not */
private boolean
atRoot;
/** The current path in the XML tree (i.e. /a/b/c) */
private
String path;
/** maintains a stack of previously encountered paths */
private
ArrayList pathStack;
/** maintains a stack of previously encountered handlers */
private
ArrayList handlerStack;
/**
* <code>HashMap</code> maintains the mapping between element paths and
* handlers
*/
private
HashMap handlers;
/**
* <code>ElementHandler</code> to use by default for element paths with no
* handlers registered
*/
private
ElementHandler defaultHandler;
public
DispatchHandler() {
atRoot = true;
path = "/";
pathStack = new
ArrayList();
handlerStack = new
ArrayList();
handlers = new
HashMap();
}
/**
* Adds the <code>ElementHandler</code> to be called when the specified
* path is encounted.
*
* @param handlerPath
* is the path to be handled
* @param handler
* is the <code>ElementHandler</code> to be called by the event
* based processor.
*/
public void
addHandler(
String handlerPath,
ElementHandler handler) {
handlers.
put(
handlerPath,
handler);
}
/**
* Removes the <code>ElementHandler</code> from the event based processor,
* for the specified path.
*
* @param handlerPath
* is the path to remove the <code>ElementHandler</code> for.
*
* @return DOCUMENT ME!
*/
public
ElementHandler removeHandler(
String handlerPath) {
return (
ElementHandler)
handlers.
remove(
handlerPath);
}
/**
* DOCUMENT ME!
*
* @param handlerPath
* DOCUMENT ME!
*
* @return true when an <code>ElementHandler</code> is registered for the
* specified path.
*/
public boolean
containsHandler(
String handlerPath) {
return
handlers.
containsKey(
handlerPath);
}
/**
* Get the registered {@link ElementHandler}for the specified path.
*
* @param handlerPath
* XML path to get the handler for
*
* @return the registered handler
*/
public
ElementHandler getHandler(
String handlerPath) {
return (
ElementHandler)
handlers.
get(
handlerPath);
}
/**
* Returns the number of {@link ElementHandler}objects that are waiting for
* their elements closing tag.
*
* @return number of active handlers
*/
public int
getActiveHandlerCount() {
return
handlerStack.
size();
}
/**
* When multiple <code>ElementHandler</code> instances have been
* registered, this will set a default <code>ElementHandler</code> to be
* called for any path which does <b>NOT </b> have a handler registered.
*
* @param handler
* is the <code>ElementHandler</code> to be called by the event
* based processor.
*/
public void
setDefaultHandler(
ElementHandler handler) {
defaultHandler =
handler;
}
/**
* Used to remove all the Element Handlers and return things back to the way
* they were when object was created.
*/
public void
resetHandlers() {
atRoot = true;
path = "/";
pathStack.
clear();
handlerStack.
clear();
handlers.
clear();
defaultHandler = null;
}
/**
* DOCUMENT ME!
*
* @return the current path for the parse
*/
public
String getPath() {
return
path;
}
// The following methods implement the ElementHandler interface
public void
onStart(
ElementPath elementPath) {
Element element =
elementPath.
getCurrent();
// Save the location of the last (i.e. parent) path
pathStack.
add(
path);
// Calculate the new path
if (
atRoot) {
path =
path +
element.
getName();
atRoot = false;
} else {
path =
path + "/" +
element.
getName();
}
if ((
handlers != null) && (
handlers.
containsKey(
path))) {
// The current node has a handler associated with it.
// Find the handler and save it on the handler stack.
ElementHandler handler = (
ElementHandler)
handlers.
get(
path);
handlerStack.
add(
handler);
// Call the handlers onStart method.
handler.
onStart(
elementPath);
} else {
// No handler is associated with this node, so use the
// defaultHandler it it exists.
if (
handlerStack.
isEmpty() && (
defaultHandler != null)) {
defaultHandler.
onStart(
elementPath);
}
}
}
public void
onEnd(
ElementPath elementPath) {
if ((
handlers != null) && (
handlers.
containsKey(
path))) {
// This node has a handler associated with it.
// Find the handler and pop it from the handler stack.
ElementHandler handler = (
ElementHandler)
handlers.
get(
path);
handlerStack.
remove(
handlerStack.
size() - 1);
// Call the handlers onEnd method
handler.
onEnd(
elementPath);
} else {
// No handler is associated with this node, so use the
// defaultHandler it it exists.
if (
handlerStack.
isEmpty() && (
defaultHandler != null)) {
defaultHandler.
onEnd(
elementPath);
}
}
// Set path back to its parent
path = (
String)
pathStack.
remove(
pathStack.
size() - 1);
if (
pathStack.
size() == 0) {
atRoot = true;
}
}
}
/*
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain copyright statements and
* notices. Redistributions must also contain a copy of this document.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name "DOM4J" must not be used to endorse or promote products derived
* from this Software without prior written permission of MetaStuff, Ltd. For
* written permission, please contact dom4j-info@metastuff.com.
*
* 4. Products derived from this Software may not be called "DOM4J" nor may
* "DOM4J" appear in their names without prior written permission of MetaStuff,
* Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
*
* 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
*
* THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
*/