org.metafacture.io.LineReader Maven / Gradle / Ivy

Go to download
/*
 * 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.io;

import org.metafacture.framework.FluxCommand;
import org.metafacture.framework.MetafactureException;
import org.metafacture.framework.ObjectReceiver;
import org.metafacture.framework.annotations.Description;
import org.metafacture.framework.annotations.In;
import org.metafacture.framework.annotations.Out;
import org.metafacture.framework.helpers.DefaultObjectPipe;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;

/**
 * Processes input from a reader line by line.
 *
 * @author Christoph Böhme
 *
 */
@Description("Processes input from a reader line by line.")
@In(Reader.class)
@Out(String.class)
@FluxCommand("as-lines")
public final class LineReader extends DefaultObjectPipe> {

    private static final int BUFFER_SIZE = 1024 * 1024 * 16;

    /**
     * Creates an instance of {@link LineReader}.
     */
    public LineReader() {
    }

    @Override
    public void process(final Reader reader) {
        assert !isClosed();
        assert null != reader;
        process(reader, getReceiver());
    }

    /**
     * Processes input from a reader and passes it line by line to a receiver.
     *
     * @param reader   the Reader
     * @param receiver the ObjectReceiver
     */
    public static void process(final Reader reader, final ObjectReceiver receiver) {
        final BufferedReader lineReader = new BufferedReader(reader, BUFFER_SIZE);
        try {
            String line = lineReader.readLine();
            while (line != null) {
                receiver.process(line);
                line = lineReader.readLine();
            }
        }
        catch (final IOException e) {
            throw new MetafactureException(e);
        }
    }

}