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

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Here is the source code for org.danann.cernunnos.io.CopyFileTask.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.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.danann.cernunnos.AttributePhrase;
import org.danann.cernunnos.Attributes;
import org.danann.cernunnos.EntityConfig;
import org.danann.cernunnos.Formula;
import org.danann.cernunnos.Phrase;
import org.danann.cernunnos.Reagent;
import org.danann.cernunnos.ReagentType;
import org.danann.cernunnos.ResourceHelper;
import org.danann.cernunnos.SimpleFormula;
import org.danann.cernunnos.SimpleReagent;
import org.danann.cernunnos.Task;
import org.danann.cernunnos.TaskRequest;
import org.danann.cernunnos.TaskResponse;

public final class CopyFileTask implements Task {

    // Instance Members.
    private final ResourceHelper resource = new ResourceHelper();
    private Phrase to_dir;
    private Phrase to_file;
    private final Log log = LogFactory.getLog(CopyFileTask.class); // Don't declare as static in general libraries

    /*
     * Public API.
     */

    public static final Reagent TO_DIR = new SimpleReagent("TO_DIR", "@to-dir", ReagentType.PHRASE, String.class,
            "Optional file system directory to which the specified resource will be copied.  It may be "
                    + "absolute or relative.  If relative, it will be evaluated from the directory in "
                    + "which Java is executing.",
            null);

    public static final Reagent TO_FILE = new SimpleReagent("TO_FILE", "@to-file", ReagentType.PHRASE, String.class,
            "Optional file system path to which the specified resource will be copied.  It may be absolute "
                    + "or relative (in which case the location will be evaluated relative to the TO_DIR).  "
                    + "If omitted, the the value of the 'Attributes.LOCATION' request attribute will be used.",
            new AttributePhrase(Attributes.LOCATION));

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

    public void init(EntityConfig config) {

        // Instance Members.
        this.resource.init(config);
        this.to_dir = (Phrase) config.getValue(TO_DIR);
        this.to_file = (Phrase) config.getValue(TO_FILE);

    }

    public void perform(TaskRequest req, TaskResponse res) {

        URL loc = resource.evaluate(req, res);
        String dir = to_dir != null ? (String) to_dir.evaluate(req, res) : null;
        String destination = (String) to_file.evaluate(req, res);

        InputStream is = null;
        OutputStream os = null;
        try {

            URLConnection conn = loc.openConnection();
            conn.connect();
            is = conn.getInputStream();

            if (log.isTraceEnabled()) {
                StringBuilder msg = new StringBuilder();
                msg.append("\n\turl=").append(loc.toString()).append("\n\tcontent-length=")
                        .append(conn.getContentLength());
                log.trace(msg);
            }

            File f = new File(dir, destination);
            if (f.getParentFile() != null) {
                // Make sure the necessary directories are in place...
                f.getParentFile().mkdirs();
            }
            os = new FileOutputStream(f);

            int bytesRead = 0;
            byte[] buf = new byte[4096];
            for (int len = is.read(buf); len > 0 || bytesRead < conn.getContentLength(); len = is.read(buf)) {
                os.write(buf, 0, len);
                bytesRead = bytesRead + len;
            }

        } catch (Throwable t) {
            String msg = "Unable to copy the specified file [" + loc.toExternalForm()
                    + "] to the specified location [" + destination + "].";
            throw new RuntimeException(msg, t);
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException ioe) {
                    throw new RuntimeException(ioe);
                }
            }
            if (os != null) {
                try {
                    os.close();
                } catch (IOException ioe) {
                    throw new RuntimeException(ioe);
                }
            }
        }

    }

}