non-releases/trunk_before_flattening/src/java/org/apache/cocoon/generation/FileGenerator.java

/*
 * Copyright 1999-2005 The Apache Software Foundation.
 *
 * 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.apache.cocoon.generation;

import org.apache.avalon.framework.parameters.Parameters;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.components.source.SourceUtil;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.excalibur.source.Source;
import org.apache.excalibur.source.SourceException;
import org.apache.excalibur.source.SourceValidity;
import org.xml.sax.SAXException;

import java.io.IOException;
import java.io.Serializable;
import java.util.Map;

/**
 * @cocoon.sitemap.component.documentation
 * The <code>FileGenerator</code> is a class that reads XML from a source
 * and generates SAX Events. The <code>FileGenerator</code> implements the
 * <code>CacheableProcessingComponent</code> interface.
 *
 * <br>See {@link FileGeneratorFactory} for thread safe implementation of this
 * component.
 *
 * @cocoon.sitemap.component.name   file
 * @cocoon.sitemap.component.label  content
 * @cocoon.sitemap.component.logger sitemap.generator.file
 * @cocoon.sitemap.component.documentation.caching
 *     Uses the last modification date of the xml document for validation
 *
 * @cocoon.sitemap.component.pooling.max  32
 *
 * @version $Id$
 */
public class FileGenerator extends ServiceableGenerator
                           implements CacheableProcessingComponent {

    /** The input source */
    protected Source inputSource;

    /**
     * Recycle this component.
     * All instance variables are set to <code>null</code>.
     */
    public void recycle() {
        if (null != this.inputSource) {
            super.resolver.release(this.inputSource);
            this.inputSource = null;
        }
        super.recycle();
    }

    /**
     * Setup the file generator.
     * Try to get the last modification date of the source for caching.
     */
    public void setup(SourceResolver resolver, Map objectModel, String src, Parameters par)
    throws ProcessingException, SAXException, IOException {

        super.setup(resolver, objectModel, src, par);
        try {
            this.inputSource = super.resolver.resolveURI(src);
        } catch (SourceException se) {
            throw SourceUtil.handle("Error during resolving of '" + src + "'.", se);
        }
    }

    /**
     * Generate the unique key.
     * This key must be unique inside the space of this component.
     *
     * @return The generated key hashes the src
     */
    public Serializable getKey() {
        return this.inputSource.getURI();
    }

    /**
     * Generate the validity object.
     *
     * @return The generated validity object or <code>null</code> if the
     *         component is currently not cacheable.
     */
    public SourceValidity getValidity() {
        return this.inputSource.getValidity();
    }

    /**
     * Generate XML data.
     */
    public void generate()
    throws IOException, SAXException, ProcessingException {

        try {
            if (getLogger().isDebugEnabled()) {
                getLogger().debug("Source " + super.source +
                                  " resolved to " + this.inputSource.getURI());
            }
            SourceUtil.parse(this.manager, this.inputSource, super.xmlConsumer);
        } catch (SAXException e) {
            SourceUtil.handleSAXException(this.inputSource.getURI(), e);
        }
    }
}