AbstractStreamExporterImpl.java

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2010, Red Hat Middleware LLC, and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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.jboss.shrinkwrap.impl.base.exporter;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.logging.Logger;

import org.jboss.shrinkwrap.api.Archive;
import org.jboss.shrinkwrap.api.exporter.ArchiveExportException;
import org.jboss.shrinkwrap.api.exporter.FileExistsException;
import org.jboss.shrinkwrap.api.exporter.StreamExporter;
import org.jboss.shrinkwrap.impl.base.AssignableBase;
import org.jboss.shrinkwrap.impl.base.io.IOUtil;

/**
 * Base support for I/O Stream-based exporters
 *
 * @author <a href="mailto:andrew.rubinger@jboss.org">ALR</a>
 */
public abstract class AbstractStreamExporterImpl extends AssignableBase<Archive<?>> implements StreamExporter {

    // -------------------------------------------------------------------------------------||
    // Class Members ----------------------------------------------------------------------||
    // -------------------------------------------------------------------------------------||

    /**
     * Logger
     */
    private static final Logger log = Logger.getLogger(AbstractStreamExporterImpl.class.getName());

    // -------------------------------------------------------------------------------------||
    // Constructor ------------------------------------------------------------------------||
    // -------------------------------------------------------------------------------------||

    public AbstractStreamExporterImpl(final Archive<?> archive) {
        super(archive);
    }

    // -------------------------------------------------------------------------------------||
    // Functional Methods -----------------------------------------------------------------||
    // -------------------------------------------------------------------------------------||

    /**
     * Obtains an {@link OutputStream} to the provided {@link File}.
     *
     * @param target
     * @param overwrite
     *            Whether we may overwrite an existing file
     * @return
     * @throws FileExistsException
     *             If the specified file exists and the overwrite flag is false
     * @throws IllegalArgumentException
     *             If the file target is not specified
     */
    protected final OutputStream getOutputStreamToFile(final File target, final boolean overwrite)
        throws FileExistsException {
        // Precondition checks
        if (target == null) {
            throw new IllegalArgumentException("Target file must be specified");
        }
        if (target.isDirectory()) {
            throw new IllegalArgumentException("Cannot export a stream file to existing directory: "
                + target.getAbsolutePath());
        }
        // If target exists and we're not allowed to overwrite it
        if (target.exists() && !overwrite) {
            throw new FileExistsException("Target exists and we haven't been flagged to overwrite it: "
                + target.getAbsolutePath());
        }

        // Get Stream
        final OutputStream out;
        try {
            out = new FileOutputStream(target);
        } catch (final FileNotFoundException e) {
            throw new ArchiveExportException("File could not be created: " + target);
        }

        // Return
        return out;
    }

    /**
     * {@inheritDoc}
     *
     * @see org.jboss.shrinkwrap.api.exporter.StreamExporter#exportTo(java.io.OutputStream)
     */
    @Override
    public void exportTo(final OutputStream target) throws ArchiveExportException, IllegalArgumentException {
        // Precondition checks
        if (target == null) {
            throw new IllegalArgumentException("Target must be specified");
        }

        // Get Stream
        final InputStream in = this.exportAsInputStream();

        try {
            // Write out
            try {
                IOUtil.copy(in, target);
            } catch (final IOException e) {
                throw new ArchiveExportException("Error encountered in exporting archive to " + target, e);
            }
        } finally {
            // Close
            try {
                in.close();
            } catch (final IOException ioe) {
                // Just log
                log.warning("Could not close " + in + ": " + ioe);
            }
        }
    }

    /**
     * {@inheritDoc}
     *
     * @see org.jboss.shrinkwrap.api.exporter.StreamExporter#exportTo(java.io.File, boolean)
     */
    @Override
    public final void exportTo(final File target, final boolean overwrite) throws ArchiveExportException,
        FileExistsException {
        // Get stream and perform precondition checks
        final OutputStream out = this.getOutputStreamToFile(target, overwrite);

        try {
            // Write out
            this.exportTo(out);
        } finally {
            // Close
            try {
                out.close();
            } catch (final IOException ioe) {
                // Just log
                log.warning("Could not close " + out + ": " + ioe);
            }
        }
    }

    /**
     * {@inheritDoc}
     *
     * @see org.jboss.shrinkwrap.api.exporter.StreamExporter#exportTo(java.io.File)
     */
    @Override
    public final void exportTo(final File target) throws ArchiveExportException, FileExistsException {
        this.exportTo(target, false);
    }

}