org.gridgain.grid.ggfs.mapreduce.GridGgfsInputStreamJobAdapter Maven / Gradle / Ivy

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Java-based middleware for in-memory processing of big data in a distributed environment.

There is a newer version: 6.2.1-p1

/* 
 Copyright (C) GridGain Systems. All Rights Reserved.
 
 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.gridgain.grid.ggfs.mapreduce;

import org.gridgain.grid.*;
import org.gridgain.grid.ggfs.*;
import org.gridgain.grid.util.*;

import java.io.*;

/**
 * Convenient {@link GridGgfsJob} adapter. It limits data returned from {@link GridGgfsInputStream} to bytes within
 * the {@link GridGgfsFileRange} assigned to the job.
 * 
 * Under the covers it simply puts job's {@code GridGgfsInputStream} position to range start and wraps in into
 * {@link GridFixedSizeInputStream} limited to range length.
 */
public abstract class GridGgfsInputStreamJobAdapter extends GridGgfsJobAdapter {
    /** {@inheritDoc} */
    @Override public final Object execute(GridGgfs ggfs, GridGgfsFileRange range, GridGgfsInputStream in)
        throws GridException, IOException {
        in.seek(range.start());

        return execute(ggfs, new GridGgfsRangeInputStream(in, range));
    }

    /**
     * Executes this job.
     *
     * @param ggfs GGFS instance.
     * @param in Input stream.
     * @return Execution result.
     * @throws GridException If execution failed.
     * @throws IOException If IO exception encountered while working with stream.
     */
    public abstract Object execute(GridGgfs ggfs, GridGgfsRangeInputStream in) throws GridException, IOException;
}