/* ========================================================================
* JCommon : a free general purpose class library for the Java(tm) platform
* ========================================================================
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------
* FrontendDefaultHandler.java
* ------------
* (C) Copyright 2002-2005, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* $Id: FrontendDefaultHandler.java,v 1.7 2005/10/18 13:25:44 mungady Exp $
*
* Changes
* -------
* 02-Feb-2005 : Initial version.
*
*/
package org.jfree.xml;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;
import java.util.Enumeration;
import org.jfree.util.Configuration;
import org.jfree.util.DefaultConfiguration;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* The frontenddefault handler connects the SAX-backend with the handler implementations.
* It must be the base class for all parser implementations used by the ParserFrontEnd.
*
* @author Thomas Morgner
*/
public abstract class FrontendDefaultHandler extends DefaultHandler implements Configuration {
/**
* A key for the content base.
*/
public static final String CONTENTBASE_KEY = "content-base";
/**
* Storage for the parser configuration.
*/
private DefaultConfiguration parserConfiguration;
/**
* The DocumentLocator can be used to resolve the current parse position.
*/
private Locator locator;
/**
* The current comment handler used to receive xml comments.
*/
private final CommentHandler commentHandler;
/**
* Default constructor.
*/
protected FrontendDefaultHandler() {
this.parserConfiguration = new DefaultConfiguration();
this.commentHandler = new CommentHandler();
}
/**
* Returns the comment handler that is used to collect comments.
*
* @return the comment handler.
*/
public CommentHandler getCommentHandler() {
return this.commentHandler;
}
/**
* Receive an object for locating the origin of SAX document events.
* <p/>
* The locator allows the application to determine the end position of
* any document-related event, even if the parser is not reporting an
* error. Typically, the application will use this information for
* reporting its own errors (such as character content that does not
* match an application's business rules). The information returned by
* the locator is probably not sufficient for use with a search engine.
*
* @param locator the locator.
*/
public void setDocumentLocator(final Locator locator) {
this.locator = locator;
}
/**
* Returns the current locator.
*
* @return the locator.
*/
public Locator getLocator() {
return this.locator;
}
/**
* Returns the configuration property with the specified key.
*
* @param key the property key.
* @return the property value.
*/
public String getConfigProperty(final String key) {
return getConfigProperty(key, null);
}
/**
* Returns the configuration property with the specified key (or the specified default value
* if there is no such property).
* <p/>
* If the property is not defined in this configuration, the code will lookup the property in
* the parent configuration.
*
* @param key the property key.
* @param defaultValue the default value.
* @return the property value.
*/
public String getConfigProperty(final String key, final String defaultValue) {
return this.parserConfiguration.getConfigProperty(key, defaultValue);
}
/**
* Sets a parser configuration value.
*
* @param key the key.
* @param value the value.
*/
public void setConfigProperty(final String key, final String value) {
if (value == null) {
this.parserConfiguration.remove(key);
}
else {
this.parserConfiguration.setProperty(key, value);
}
}
public Enumeration getConfigProperties()
{
return parserConfiguration.getConfigProperties();
}
/**
* Returns a new instance of the parser.
*
* @return a new instance of the parser.
*/
public abstract FrontendDefaultHandler newInstance();
/**
* Returns all keys with the given prefix.
*
* @param prefix the prefix
* @return the iterator containing all keys with that prefix
*/
public Iterator findPropertyKeys(final String prefix) {
return this.parserConfiguration.findPropertyKeys(prefix);
}
/**
* Returns the parse result. This method is called at the end of the
* parsing process and expects the generated object.
*
* @return the object.
* @throws SAXException if something went wrong.
*/
public abstract Object getResult() throws SAXException;
/**
* Gets the ContentBase used to resolve relative URLs.
*
* @return the current contentbase, or null if no contentBase is set.
*/
public URL getContentBase() {
final String contentBase = getConfigProperty(Parser.CONTENTBASE_KEY);
if (contentBase == null) {
return null;
}
try {
return new URL(contentBase);
}
catch (MalformedURLException mfe) {
throw new IllegalStateException("Content Base is illegal." + contentBase);
}
}
}