saxhandler.java

非常接近C/S操作方式的Java Ajax框架－ZK 用ZK框架使你的B/S应用程序更漂亮更易操作。 官网：www.zkoss.org

/* SAXHandler.java

{{IS_NOTE

	Purpose:
	Description:
	History:
	2001/10/25 12:34:46, Create, Tom M. Yeh.
}}IS_NOTE

Copyright (C) 2001 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
	This program is distributed under GPL Version 2.0 in the hope that
	it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.idom.input;

import java.util.Stack;
import java.util.List;
import java.util.LinkedList;
import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;
import java.io.IOException;
import java.net.URL;

import javax.xml.parsers.SAXParser;

import org.xml.sax.Locator;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.InputSource;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.ext.DeclHandler;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.XMLReader;

import org.zkoss.lang.D;
import org.zkoss.lang.Objects;
import org.zkoss.util.logging.Log;
import org.zkoss.util.resource.Locators;
import org.zkoss.idom.util.SimpleLocator;
import org.zkoss.idom.*;

/**
 * The SAX Hanlder.
 * It implements ContentHandler, LexicalHandler and DeclHandler.
 * It is the caller's job to set up this handler properly if required.
 *
 * <p>This class doesn't depend on SAXBuilder, so it can be used in any
 * other place, e.g., javax.xml.transform.sax.SAXResult.
 *
 * @author tomyeh
 * @see SAXBuilder
 */
public class SAXHandler extends DefaultHandler
implements LexicalHandler, DeclHandler {
	private static final Log log = Log.lookup(SAXHandler.class);

	/** The iDOM factory. */
	protected IDOMFactory _factory;

	//-- options --//
	/** Whether to ignore ignorable whitespace */
	private boolean _ignoreWhitespaces = false;
	/** Whether expansion of entities should occur */
	private boolean _expandEntities = true;
	/** Whether to convert CDATA to Text and coalesce them. */
	private boolean _coalescing = false;
	/** Whether to ignore comments. */
	private boolean _ignoreComments = false;
	/** The error handler. */
	private ErrorHandler _errHandler = null;
	/** The entity resolver. */
	private EntityResolver _resolver = null;

	/** The Document being created. */
	protected Document _doc = null;
	/** Locator. */
	protected Locator _loc = null;
	/** Indicator of whether we are in a DTD. */
	protected boolean _inDTD = false;
	/** Indicator of whether we are in a CDATA. */
	protected boolean _inCData = false;
	/** The Group stack. The top one is the current group being processed. */
	protected Stack _stack = null;
	/** The namespaces in between startPrefixMapping and endPrefixMapping. */
	protected List _declNamespaces = null;
	/** Temporary holder for the internal subset. */
	private StringBuffer _internSubset = null;
	/** Whether it is in internal subset. */
	private boolean _inInternSubset = false;

	/**
	 * Constructor.
	 *
	 * @param factory the iDOM factory; null for DefaultIDOMFactory.
	 */
	public SAXHandler(IDOMFactory factory) {
		_factory = factory != null ? factory: new DefaultIDOMFactory();
	}
	/**
	 * Constructor.
	 */
	public SAXHandler() {
		_factory = new DefaultIDOMFactory();
	}

	//-- options --//
	/**
	 * Tests whether to ignore whitespaces in element content.
	 */
	public final boolean isIgnoringElementContentWhitespace() {
		return _ignoreWhitespaces;
	}
	/**
	 * Sets whether the parser should elminate whitespace in 
	 * element content. They are known as "ignorable whitespace". 
	 * Only whitespace which is contained within element content that has
	 * an element only content model will be eliminated (see XML Rec 2.10).
	 *
	 * <p>For this setting to take effect requires that validation be turned on.
	 *
	 * <p>Default: false.
	 *
	 * @param ignore Whether to ignore whitespaces in element content.
	 */
	public final void setIgnoringElementContentWhitespace(boolean ignore) {
		_ignoreWhitespaces = ignore;
	}

	/**
	 * Tests whether to expand entity reference nodes.
	 */
	public final boolean isExpandEntityReferences() {
		return _expandEntities;
	}
	/**
	 * Sets whether to expand entities during parsing.
	 * A true means to expand entities as normal content.  A false means to
	 * leave entities unexpanded as <code>EntityReference</code> objects.
	 *
	 * <p>Default: true.
	 *
	 * @param expand whether entity expansion should occur.
	 */
	public final void setExpandEntityReferences(boolean expand) {
		_expandEntities = expand;
	}

	/**
	 * Indicates whether or not the factory is configured to produce parsers
	 * which converts CDATA to Text and appends it to the adjacent (if any)
	 * Text node.
	 *
	 * <p>Default: false.
	 *
	 * @return true if the factory is configured to produce parsers which
	 * converts CDATA nodes to Text nodes
	 * and appends it to the adjacent (if any) Text node; false otherwise.
	 */
	public final boolean isCoalescing() {
		return _coalescing;
	}
	/**
	 * Specifies that the parser produced by this code will convert
	 * CDATA to Text and append it to the adjacent (if any) text.
	 *
	 * <p>Default: false.
	 */
	public final void setCoalescing(boolean coalescing) {
		_coalescing = coalescing;
	}

	/**
	 * Indicates whether or not the factory is configured to produce parsers
	 * which ignores comments.
	 *
	 * <p>Default: false.
	 *
	 * @return true if the factory is configured to produce parsers
	 * which ignores comments; false otherwise.
	 */
	public final boolean isIgnoringComments() {
		return _ignoreComments;
	}
	/**
	 * Specifies that the parser produced by this code will ignore comments.
	 *
	 * <p>Default: false.
	 */
	public final void setIgnoringComments(boolean ignoreComments) {
		_ignoreComments = ignoreComments;
	}

	/**
	 * Specifies the org.xml.sax.ErrorHandler to be used to report errors
	 * present in the XML document to be parsed.
	 * <p>Default: null -- to use the default imple-mentation and behavior.
	 */
	public final void setErrorHandler(ErrorHandler eh) {
		_errHandler = eh;
	}
	/**
	 * Gets the org.xml.sax.ErrorHandler.
	 *
	 * @return the error handler; null to use the default implementation
	 */
	public final ErrorHandler getErrorHandler() {
		return _errHandler;
	}

	/**
	 * Specifies the org.xml.sax.EntityResolver to be used to resolve
	 * entities present in the XML docu-ment to be parsed.
	 * <p>Default: null -- to use the default implementation and behavior.
	 */
	public final void setEntityResolver(org.xml.sax.EntityResolver er) {
		_resolver = er;
	}
	/**
	 * Gets the org.xml.sax.EntityResolver.
	 *
	 * @return the enity resolverr; null to use the default implementation
	 */
	public final EntityResolver getEntityResolver() {
		return _resolver;
	}

	//-- Extra utilities for the caller to use --//
	/**
	 * Gets the document being created.
	 * Called to retrieve the iDOM tree after parsed.
	 */
	public final Document getDocument() {
		return _doc;
	}

	/**
	 * Gets the iDOM factory. Null for DefaultIDOMFactory.THE.
	 */
	public final IDOMFactory getIDOMFactory() {
		return _factory;
	}
	/**
	 * Sets the iDOM factory. Null for DefaultIDOMFactory.THE.
	 */
	public final void setIDOMFactory(IDOMFactory factory) {
		_factory = factory;
	}

	//-- protected utilities --//
	/**
	 * Attaches the locator to the item.
	 */
	protected final void attachLocator(Item vtx) {
		if (_loc != null)
			vtx.setLocator(new SimpleLocator(_loc));
	}

	/** Returns the top group, or null if not available.
	 */
	protected final Group getTopGroup() {
		return _stack.isEmpty() ? null: (Group)_stack.peek();
	}
	/**
	 * Adds the item to the current group; also attach the locator.
	 */
	protected final void addToCurrentGroup(Item vtx) {
		attachLocator(vtx);
		((Group)_stack.peek()).getChildren().add(vtx);
	}
	/**
	 * Adds a new group to the current group as a child,
	 * and pushes the new group to be the new current group.
	 */
	protected final void pushGroup(Group group) {
		if (_stack.isEmpty())
			assert(group instanceof Document);
		else
			addToCurrentGroup(group);

		_stack.push(group);
	}
	/**
	 * Pops out the current group, and the one under it becomes the
	 * new current group.
	 */
	protected final void popGroup() {
		((Group)_stack.pop()).coalesce(false);
	}

	//-- org.xml.sax.ext.DeclHandler --//
	public void externalEntityDecl(String name, String pubId, String sysId)
	throws SAXException {
		if (D.ON && log.finerable())
			log.finer("externalEntityDecl: " + name + " p:" + pubId + " s:" + sysId);

		if (!_inInternSubset)
			return;

		_internSubset.append("  <!ENTITY ").append(name);
		if (pubId != null)
			_internSubset.append(" PUBLIC \"").append(pubId).append("\" ");
		if (sysId != null)
			_internSubset.append(" SYSTEM \"").append(sysId).append("\" ");
		_internSubset.append(">\n");
	}

	public void internalEntityDecl(String name, String value)
	throws SAXException { 
		if (D.ON && log.finerable()) log.finer("internalEntityDecl: " + name + '=' + value);

		if (!_inInternSubset)
			return;

		_internSubset.append("  <!ENTITY ").append(name).append(" \"")
			.append(value).append("\">\n");
	}

	public void attributeDecl(String eName, String aName, String type,
	String valueDefault, String value) throws SAXException {
		if (!_inInternSubset)
			return;

		_internSubset.append("  <!ATTLIST ").append(eName).append(' ')
			.append(aName).append(' ').append(type).append(' ');
		if (valueDefault != null) {
			_internSubset.append(valueDefault);
		} else {
			_internSubset.append('"').append(value).append('"');
		}
		if ((valueDefault != null) && (valueDefault.equals("#FIXED"))) {
			_internSubset.append(" \"").append(value).append('"');
		}
		_internSubset.append(">\n");
	}

	public void elementDecl(String name, String model) throws SAXException {
		if (!_inInternSubset)
			return;

		_internSubset.append("  <!ELEMENT ").append(name).append(' ')
			.append(model).append(">\n");
	}

	//-- org.xml.sax.ext.LexicalHandler --//
	public void startDTD(String name, String pubId, String sysId)
	throws SAXException {
		if (D.ON && log.finerable())
			log.finer("start DTD: " + name + " p:" + pubId + " s:" + sysId);

		addToCurrentGroup(_factory.newDocType(name, pubId, sysId));
		_inDTD = true;
		_internSubset = new StringBuffer(); //TY: start use it
		_inInternSubset = true;
	}

	//NOTE: xerces does not invoke endDTD if nothing in there
	public void endDTD() throws SAXException {
		if (D.ON && log.finerable()) log.finer("end DTD: \"" + _internSubset + '"');

		_doc.getDocType().setInternalSubset(_internSubset.toString());
		_inDTD = false;
		_internSubset = null; //TY: no longer used
		_inInternSubset = false;
	}