com.knewton.mrtool.io.SeekableByteArrayInputStream.java Source code

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Here is the source code for com.knewton.mrtool.io.SeekableByteArrayInputStream.java

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/**
 * Copyright 2013 Knewton
 * 
 * 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 com.knewton.mrtool.io;

import org.apache.hadoop.fs.PositionedReadable;
import org.apache.hadoop.fs.Seekable;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Helper input stream which composes a {@link ByteArrayInputStream} and implements {@link Seekable}
 * and {@link PositionedReadable} for testing the {@link JsonRecordReader}
 * 
 */
public class SeekableByteArrayInputStream extends InputStream implements Seekable, PositionedReadable {

    private ByteArrayInputStream inputStream;
    private long pos;

    public SeekableByteArrayInputStream(byte[] recommendationBytes) {
        this.inputStream = new ByteArrayInputStream(recommendationBytes);
        pos = 0;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void seek(long pos) throws IOException {
        inputStream.skip(pos);
        this.pos = pos;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public long getPos() throws IOException {
        return pos;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean seekToNewSource(long targetPos) throws IOException {
        throw new UnsupportedOperationException("seekToNewSource is not supported.");
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int read() throws IOException {
        int val = inputStream.read();
        if (val > 0) {
            pos++;
        }
        return val;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int read(long position, byte[] buffer, int offset, int length) throws IOException {
        long currPos = pos;
        inputStream.skip(position);
        int bytesRead = inputStream.read(buffer, offset, length);
        inputStream.skip(currPos);
        return bytesRead;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void readFully(long position, byte[] buffer, int offset, int length) throws IOException {
        long currPos = pos;
        inputStream.skip(position);
        inputStream.read(buffer, offset, length);
        inputStream.skip(currPos);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void readFully(long position, byte[] buffer) throws IOException {
        long currPos = pos;
        inputStream.skip(position);
        inputStream.read(buffer);
        inputStream.skip(currPos);
    }

}