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/*
 * Copyright 2013, 2014 Deutsche Nationalbibliothek
 *
 * 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.metafacture.triples;

import org.metafacture.framework.FluxCommand;
import org.metafacture.framework.MetafactureException;
import org.metafacture.framework.annotations.Description;
import org.metafacture.framework.annotations.In;
import org.metafacture.framework.annotations.Out;
import org.metafacture.framework.helpers.DefaultObjectReceiver;
import org.metafacture.framework.objects.Triple;

import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;

/**
 * @author Christoph Böhme
 *
 */
@Description("Writes triples into a file.")
@In(Triple.class)
@Out(Void.class)
@FluxCommand("write-triples")
public final class TripleWriter extends DefaultObjectReceiver {

    public static final int BUFFERSIZE = 2048;

    private final String filename;

    private ObjectOutputStream outputStream;

    /**
     * Constructs a TripleWriter with a given file name as output path.
     *
     * @param filename the name of the file to write to
     */
    public TripleWriter(final String filename) {
        this.filename = filename;
        resetStream();
    }

    @Override
    public void process(final Triple obj) {
        try {
            obj.write(outputStream);
        }
        catch (final IOException e) {
            throw new MetafactureException(e);
        }
    }

    @Override
    public void resetStream() {
        try {
            if (outputStream != null) {
                outputStream.close();
            }
            outputStream = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(filename), BUFFERSIZE));
        }
        catch (final IOException e) {
            throw new MetafactureException(e);
        }
    }

    @Override
    public void closeStream() {
        try {
            if (outputStream != null) {
                outputStream.close();
            }
        }
        catch (final IOException e) {
            throw new MetafactureException(e);
        }
    }

}