org.schedoscope.export.redis.outputformat.RedisListWritable.java Source code

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Here is the source code for org.schedoscope.export.redis.outputformat.RedisListWritable.java

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/**
 * Copyright 2016 Otto (GmbH & Co KG)
 *
 * 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.schedoscope.export.redis.outputformat;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

import org.apache.hadoop.io.ArrayWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.Pipeline;

/**
 * A writable to store arrays, provides a function to write the data into Redis.
 */
public class RedisListWritable implements RedisWritable, Writable {

    private Text key;

    private ArrayWritable value;

    /**
     * Default constructor, initializes the internal writables.
     */
    public RedisListWritable() {

        key = new Text();
        value = new ArrayWritable(Text.class);
    }

    /**
     * Constructor to initialize with a key and a list of elements.
     * 
     * @param key
     *            The key to use for Redis.
     * @param value
     *            The data to write into Redis.
     */
    public RedisListWritable(String key, List<String> value) {

        this.key = new Text(String.valueOf(key));
        this.value = toArrayWritable(value);
    }

    /**
     * A constructor setting the internal writables.
     *
     * @param key
     *            The Redis key
     * @param value
     *            The Redis value
     */
    public RedisListWritable(Text key, ArrayWritable value) {

        this.key = key;
        this.value = value;
    }

    @Override
    public void write(Jedis jedis, boolean replace) {

        if (replace) {
            jedis.del(key.toString());
        }
        for (String v : fromArrayWritable(value)) {
            jedis.lpush(key.toString(), v);
        }
    }

    @Override
    public void write(Pipeline jedis, boolean replace) {

        if (replace) {
            jedis.del(key.toString());
        }
        for (String v : fromArrayWritable(value)) {
            jedis.lpush(key.toString(), v);
        }
    }

    @Override
    public void write(DataOutput out) throws IOException {

        key.write(out);
        value.write(out);
    }

    @Override
    public void readFields(Jedis jedis, String key) {

        this.value = toArrayWritable(jedis.lrange(key, 0, -1));
        this.key = new Text(key);
    }

    @Override
    public void readFields(DataInput in) throws IOException {

        key.readFields(in);
        value.readFields(in);
    }

    private ArrayWritable toArrayWritable(List<String> value) {

        Text[] ar = new Text[value.size()];
        for (int i = 0; i < value.size(); i++) {
            ar[i] = new Text(value.get(i));
        }
        ArrayWritable aw = new ArrayWritable(Text.class, ar);
        return aw;
    }

    private List<String> fromArrayWritable(ArrayWritable value) {

        return Arrays.asList(value.toStrings());
    }
}