TripleWriter.java

/*
 * 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.culturegraph.mf.triples;

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

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

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

	public static final int BUFFERSIZE = 2048;

	private final String filename;

	private ObjectOutputStream outputStream;

	public TripleWriter(final String filename) {
		this.filename = filename;
		resetStream();
	}

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

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

}