org.xchain.framework.strategy.CatalogConsumerStrategy.java Source code

Introduction

Here is the source code for org.xchain.framework.strategy.CatalogConsumerStrategy.java

Source

/**
 *    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.strategy;

import org.apache.commons.digester.Digester;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xchain.Catalog;
import org.xchain.framework.digester.AnnotationRuleSet;
import org.xchain.framework.sax.XChainDeclFilter;
import org.xchain.framework.jsl.SaxTemplateHandler;
import org.xchain.framework.net.DependencyTracker;
import org.xchain.framework.lifecycle.XmlFactoryLifecycle;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

/**
 * ConsumerStrategy implementation for Catalogs.
 * 
 * @author Devon Tackett
 * @author Christian Trimble
 * @author Josh Kennedy
 *
 * @see org.xchain.Catalog
 */
public class CatalogConsumerStrategy implements ConsumerStrategy<Catalog, InputSource> {
    public static Logger log = LoggerFactory.getLogger(CatalogConsumerStrategy.class);

    public Catalog consume(String systemId, SourceStrategy<InputSource> sourceStrategy, DependencyTracker tracker)
            throws Exception {
        // Get the input source
        InputSource inputSource = sourceStrategy.getSource(systemId);

        // create the XMLReader.
        XMLReader reader = XmlFactoryLifecycle.newXmlReader();

        reader.setErrorHandler(new FailingErrorHandler());

        XChainDeclFilter sourceFilter = new XChainDeclFilter();
        sourceFilter.setParent(reader);
        sourceFilter.setErrorHandler(new FailingErrorHandler());

        // create the jsl filter.
        SaxTemplateHandler xmlFilter = new SaxTemplateHandler();
        xmlFilter.setParent(sourceFilter);
        xmlFilter.setErrorHandler(new FailingErrorHandler());

        // create the digester, passing the jsl filter.
        Digester digester = new Digester(xmlFilter);

        // set the digester onto the xml filter.
        xmlFilter.setDigester(digester);

        // add the annotation rule set to the digester.
        digester.addRuleSet(new AnnotationRuleSet(systemId));

        digester.setErrorHandler(new FailingErrorHandler());

        // get the catalog object.
        Catalog catalog = null;

        try {
            catalog = (Catalog) digester.parse(inputSource);
        } catch (Exception e) {
            if (log.isErrorEnabled()) {
                log.error("Could not create catalog for system id '" + inputSource.getSystemId() + "'.", e);
            }
            throw e;
        }

        return catalog;
    }

    public static class FailingErrorHandler implements ErrorHandler {
        public void warning(SAXParseException exception) throws SAXException {
            if (log.isWarnEnabled()) {
                log.warn("SAXParseException thrown while loading catalog.", exception);
            }
        }

        public void error(SAXParseException exception) throws SAXException {
            if (log.isErrorEnabled()) {
                log.error("SAXParseException thrown while loading catalog.", exception);
            }
            throw exception;
        }

        public void fatalError(SAXParseException exception) throws SAXException {
            if (log.isErrorEnabled()) {
                log.error("Fatal SAXParseException thrown while loading catalog.", exception);
            }
            throw exception;
        }

    }

}