org.danann.cernunnos.io.ArchiveIteratorTask.java Source code

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Here is the source code for org.danann.cernunnos.io.ArchiveIteratorTask.java

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/*
 * Copyright 2007 Andrew Wills
 *
 * 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.danann.cernunnos.io;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.net.URL;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.commons.io.IOUtils;
import org.danann.cernunnos.AbstractContainerTask;
import org.danann.cernunnos.Attributes;
import org.danann.cernunnos.EntityConfig;
import org.danann.cernunnos.Formula;
import org.danann.cernunnos.Reagent;
import org.danann.cernunnos.ResourceHelper;
import org.danann.cernunnos.SimpleFormula;
import org.danann.cernunnos.TaskRequest;
import org.danann.cernunnos.TaskResponse;

public final class ArchiveIteratorTask extends AbstractContainerTask {

    // Instance Members.
    private final ResourceHelper resource = new ResourceHelper();

    /*
     * Public API.
     */

    public Formula getFormula() {
        Reagent[] reagents = new Reagent[] { ResourceHelper.CONTEXT_TARGET, ResourceHelper.LOCATION_TASK,
                AbstractContainerTask.SUBTASKS };
        final Formula rslt = new SimpleFormula(ArchiveIteratorTask.class, reagents);
        return rslt;
    }

    public void init(EntityConfig config) {

        super.init(config);

        // Instance Members.
        resource.init(config);

    }

    public void perform(TaskRequest req, TaskResponse res) {

        URL url = resource.evaluate(req, res);
        ZipInputStream zip = null;
        try {
            final String urlExternalForm = url.toExternalForm();

            try {
                zip = new ZipInputStream(new BufferedInputStream(url.openStream()));
            } catch (IOException ioe) {
                throw new RuntimeException("Failed to open input stream for URL: " + urlExternalForm, ioe);
            }

            // Set the default CONTEXT for subtasks...
            res.setAttribute(Attributes.CONTEXT, "jar:" + urlExternalForm + "!/");

            try {
                for (ZipEntry entry = zip.getNextEntry(); entry != null; entry = zip.getNextEntry()) {
                    if (entry.isDirectory()) {
                        // We need to skip these b/c many possible subtasks will
                        // choke on them.  Hope that doesn't become a problem.
                        continue;
                    }

                    res.setAttribute(Attributes.LOCATION, entry.getName());
                    super.performSubtasks(req, res); //Outer try/catch should never see an IOException from performSubtasks

                    zip.closeEntry();
                }
            } catch (IOException ioe) {
                throw new RuntimeException("Failed to read specified archive:  " + urlExternalForm, ioe);
            }
        } finally {
            //Problems closing an InputStream can be ignored
            IOUtils.closeQuietly(zip);
        }

    }

}