safebox/guacamole-client
4
0
Fork 0
mirror of https://github.com/gyurix1968/guacamole-client.git synced 2025-09-07 13:41:21 +00:00
Code Issues Packages Projects Releases Wiki Activity

Implement MUCH simpler SAX-driven XML parser.

Browse Source
This commit is contained in:
Michael Jumper
2012-12-23 22:31:36 -08:00
parent fec906227e
commit d1663bd3a1
2 changed files with 240 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

183
guacamole/src/main/java/net/sourceforge/guacamole/net/basic/xml/DocumentHandler.java Normal file
View File

@@ -0,0 +1,183 @@
package net.sourceforge.guacamole.net.basic.xml;
/*
* Guacamole - Clientless Remote Desktop
* Copyright (C) 2010 Michael Jumper
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.util.LinkedList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* A simple ContentHandler implementation which digests SAX document events and
* produces simpler tag-level events, maintaining its own stack for the
* convenience of the tag handlers.
*
* @author Mike Jumper
*/
public class DocumentHandler extends DefaultHandler {
/**
* The name of the root element of the document.
*/
private String rootElementName;
/**
* The handler which will be used to handle element events for the root
* element of the document.
*/
private TagHandler root;
/**
* The stack of all states applicable to the current parser state. Each
* element of the stack references the TagHandler for the element being
* parsed at that level of the document, where the current element is
* last in the stack, and the root element is first.
*/
private LinkedList<DocumentHandlerState> stack =
new LinkedList<DocumentHandlerState>();
/**
* Creates a new DocumentHandler which will use the given TagHandler
* to handle the root element.
*
* @param rootElementName The name of the root element of the document
* being handled.
* @param root The TagHandler to use for the root element.
*/
public DocumentHandler(String rootElementName, TagHandler root) {
this.root = root;
this.rootElementName = rootElementName;
}
/**
* Returns the current element state. The current element state is the
* state of the element the parser is currently within.
*
* @return The current element state.
*/
private DocumentHandlerState getCurrentState() {
return stack.getLast();
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
// Get current state
DocumentHandlerState current = getCurrentState();
// Handler for tag just read
TagHandler handler;
// If no stack, use root handler
if (current == null) {
// Validate element name
if (!localName.equals(rootElementName))
throw new SAXException("Root element must be '" + rootElementName + "'");
handler = root;
}
// Otherwise, get handler from parent
else {
TagHandler parent_handler = current.getTagHandler();
handler = parent_handler.childElement(localName, attributes);
}
// Append new element state to stack
stack.addLast(new DocumentHandlerState(handler));
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
// Pop last element from stack
DocumentHandlerState completed = stack.removeLast();
// Finish element by sending text content
completed.getTagHandler().complete(
completed.getTextContent().toString());
}
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
// Append received chunk to text content
getCurrentState().getTextContent().append(ch, start, length);
}
/**
* The current state of the DocumentHandler.
*/
private class DocumentHandlerState {
/**
* The current text content of the current element being parsed.
*/
private StringBuilder textContent = new StringBuilder();
/**
* The TagHandler which must handle document events related to the
* element currently being parsed.
*/
private TagHandler tagHandler;
/**
* Creates a new DocumentHandlerState which will maintain the state
* of parsing of the current element, as well as contain the TagHandler
* which will receive events related to that element.
*
* @param tagHandler The TagHandler which should receive any events
* related to the element being parsed.
*/
public DocumentHandlerState(TagHandler tagHandler) {
this.tagHandler = tagHandler;
}
/**
* Returns the mutable StringBuilder which contains the current text
* content of the element being parsed.
*
* @return The mutable StringBuilder which contains the current text
* content of the element being parsed.
*/
public StringBuilder getTextContent() {
return textContent;
}
/**
* Returns the TagHandler which must handle any events relating to the
* element being parsed.
*
* @return The TagHandler which must handle any events relating to the
* element being parsed.
*/
public TagHandler getTagHandler() {
return tagHandler;
}
}
}

57
guacamole/src/main/java/net/sourceforge/guacamole/net/basic/xml/TagHandler.java Normal file
View File

@@ -0,0 +1,57 @@
package net.sourceforge.guacamole.net.basic.xml;
/*
* Guacamole - Clientless Remote Desktop
* Copyright (C) 2010 Michael Jumper
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
/**
* A simple element-level event handler for events triggered by the
* SAX-driven DocumentHandler parser.
*
* @author Mike Jumper
*/
public interface TagHandler {
/**
* Called when a child element of the current element is parsed.
*
* @param localName The local name of the child element seen.
* @param attributes The attributes of the child element seen.
* @return The TagHandler which should handle all element-level events
* related to the child element.
* @throws SAXException If the child element being parsed was not expected,
* or some other error prevents a proper TagHandler
* from being constructed for the child element.
*/
public TagHandler childElement(String localName, Attributes attributes)
throws SAXException;
/**
* Called when this element, and all child elements, have been fully parsed,
* and the entire text content of this element (if any) is available.
*
* @param textContent The full text content of this element, if any.
* @throws SAXException If the text content received is not valid for any
* reason, or the child elements parsed are not
* correct.
*/
public void complete(String textContent) throws SAXException;
}