org.dom4j.io.DispatchHandler Maven / Gradle / Ivy
/*
* 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;
/**
*
* DispatchHandler implements the ElementHandler
* interface and provides a means to register multiple
* ElementHandler instances to be used by an event based
* processor. This is a special ElementHandler in that it's
* onStart and onEnd implementation methods are called for every
* element encountered during the parse. It then delegates to other
* ElementHandler instances registered with it to process the
* elements encountered.
*
*
* @author Dave White
* @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;
/**
* HashMap maintains the mapping between element paths and
* handlers
*/
private HashMap handlers;
/**
* ElementHandler 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 ElementHandler to be called when the specified
* path is encounted.
*
* @param handlerPath
* is the path to be handled
* @param handler
* is the ElementHandler to be called by the event
* based processor.
*/
public void addHandler(String handlerPath, ElementHandler handler) {
handlers.put(handlerPath, handler);
}
/**
* Removes the ElementHandler from the event based processor,
* for the specified path.
*
* @param handlerPath
* is the path to remove the ElementHandler for.
*
* @return DOCUMENT ME!
*/
public ElementHandler removeHandler(String handlerPath) {
return handlers.remove(handlerPath);
}
/**
* DOCUMENT ME!
*
* @param handlerPath
* DOCUMENT ME!
*
* @return true when an ElementHandler 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 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 ElementHandler instances have been
* registered, this will set a default ElementHandler to be
* called for any path which does NOT have a handler registered.
*
* @param handler
* is the ElementHandler 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 = 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 = 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 = 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 [email protected].
*
* 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.
*/