org.xchain.framework.sax.CommandXmlReader.java Source code

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Here is the source code for org.xchain.framework.sax.CommandXmlReader.java

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/**
 *    Copyright 2011 meltmedia
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.xchain.framework.sax;

import org.xchain.Command;
import org.xchain.framework.factory.CatalogFactory;

import org.apache.commons.jxpath.JXPathContext;

import org.xml.sax.ContentHandler;
import org.xml.sax.DTDHandler;
import org.xml.sax.InputSource;
import org.xml.sax.ErrorHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.XMLReader;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.ext.LexicalHandler;
import java.io.IOException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Mike Moulton
 * @author Christian Trimble
 * @author Josh Kennedy
 */
public class CommandXmlReader implements XMLReader {
    public static Logger log = LoggerFactory.getLogger(CommandXmlReader.class);

    protected Command command = null;
    protected CommandHandler commandHandler = new CommandHandlerImpl();
    protected ContentHandler contentHandler = null;
    protected DTDHandler dtdHandler = null;
    protected ErrorHandler errorHandler = null;
    protected EntityResolver entityResolver = null;

    /**
     * Creates a command xml reader using a catalog name and a command name.
     */
    public CommandXmlReader(String catalogName, String commandName) throws SAXException {
        try {
            this.command = CatalogFactory.getInstance().getCatalog(catalogName).getCommand(commandName);
        } catch (Exception e) {
            throw new SAXException("Could not find command for catalog '" + catalogName + "' and command name '"
                    + commandName + "'.", e);
        }
    }

    /**
     * Creates a command xml reader using the provided command.
     */
    public CommandXmlReader(Command command) {
        this.command = command;
    }

    /**
     * Returns the handler that commands should use to output events.
     */
    public CommandHandler getCommandHandler() {
        return commandHandler;
    }

    public void setContentHandler(ContentHandler contentHandler) {
        this.contentHandler = contentHandler;
    }

    public ContentHandler getContentHandler() {
        return this.contentHandler;
    }

    public void setDTDHandler(DTDHandler dtdHandler) {
        this.dtdHandler = dtdHandler;
    }

    public DTDHandler getDTDHandler() {
        return this.dtdHandler;
    }

    public void setErrorHandler(ErrorHandler errorHandler) {
        this.errorHandler = errorHandler;
    }

    public ErrorHandler getErrorHandler() {
        return this.errorHandler;
    }

    public void setEntityResolver(EntityResolver entityResolver) {
        this.entityResolver = entityResolver;
    }

    public EntityResolver getEntityResolver() {
        return this.entityResolver;
    }

    public boolean sendEvents() {
        return true;
    }

    public boolean getFeature(String name) throws SAXNotRecognizedException, SAXNotSupportedException {
        throw new SAXNotRecognizedException("Property '" + name + "' is not supported.");
    }

    public void setFeature(String name, boolean value) throws SAXNotRecognizedException, SAXNotSupportedException {
        throw new SAXNotRecognizedException("Property '" + name + "' is not supported.");
    }

    public void setProperty(String name, Object value) throws SAXNotRecognizedException, SAXNotSupportedException {
        throw new SAXNotRecognizedException("Property '" + name + "' is not supported.");
    }

    public Object getProperty(String name) throws SAXNotRecognizedException, SAXNotSupportedException {
        throw new SAXNotRecognizedException("Property '" + name + "' is not supported.");
    }

    public void parse(InputSource inputSource) throws IOException, SAXException {
        if (!(inputSource instanceof ContextInputSource)) {
            throw new IllegalArgumentException("CommandXmlReaders can only parse ContextInputSources.");
        }

        // get the context from the input source.
        ContextInputSource contentInputSource = (ContextInputSource) inputSource;
        JXPathContext context = contentInputSource.getContext();

        // execute the command.
        try {
            // start the document.
            commandHandler.startDocument();

            // execute the command.
            command.execute(context);

            // end the document.
            commandHandler.endDocument();
        } catch (SAXException saxe) {
            throw saxe;
        } catch (IOException ioe) {
            throw ioe;
        } catch (Exception e) {
            //log.error("Exception thrown while parsing context.", e);
            throw new SAXException("Exception thrown while parsing context.", e);
        }
    }

    public void parse(String systemId) throws IOException, SAXException {
        throw new UnsupportedOperationException("The CommandXmlReader cannot parse a systemId.");
    }

    /**
     * This is the class that sax event commands write to.  Calling methods on this class passes the events on to
     * the content handler of the containing xml reader.
     */
    public class CommandHandlerImpl extends CommandHandler {
        public ContentHandler contentHandler() {
            return contentHandler;
        }

        public DTDHandler dtdHandler() {
            return dtdHandler;
        }

        public LexicalHandler lexicalHandler() {
            if (contentHandler instanceof LexicalHandler) {
                return (LexicalHandler) contentHandler;
            }

            return null;
        }
    }
}