com.jwsphere.accumulo.DeflateTransportCompression.java Source code

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Here is the source code for com.jwsphere.accumulo.DeflateTransportCompression.java

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/**
 * Copyright 2015 Jonathan Wonders
 *
 * 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.jwsphere.accumulo;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.List;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.InflaterInputStream;

import org.apache.accumulo.core.data.KeyValue;
import org.apache.accumulo.core.data.thrift.ScanResult;
import org.apache.accumulo.core.data.thrift.TKey;
import org.apache.accumulo.core.data.thrift.TKeyValue;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TCompactProtocol;
import org.apache.thrift.transport.TIOStreamTransport;
import org.apache.thrift.transport.TTransport;

/**
 * Compresses the batch of KeyValue pairs by encoding a ScanResult thrift
 * object and deflating the resulting bytes, storing the compressed result
 * as the value for a singleton collection of TKeyValue objects.
 */
public class DeflateTransportCompression extends TransportCompression {

    @Override
    public List<TKeyValue> compress(List<? extends KeyValue> source) {
        ScanResult result = new ScanResult(toThrift(source), false);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        DeflaterOutputStream deflateStream = new DeflaterOutputStream(baos);
        TTransport transport = new TIOStreamTransport(deflateStream);
        TCompactProtocol proto = new TCompactProtocol(transport);
        try {
            transport.open();
            result.write(proto);
        } catch (TException e) {
            throw new RuntimeException(e);
        } finally {
            transport.close();
        }
        byte[] bytes = baos.toByteArray();
        return Collections.singletonList(new TKeyValue(new TKey(), ByteBuffer.wrap(bytes)));
    }

    @Override
    public List<KeyValue> decompress(List<TKeyValue> data) {
        if (data.size() != 1) {
            throw new IllegalArgumentException("Unexpected number of results.");
        }
        byte[] bytes = data.get(0).getValue();
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        InflaterInputStream inflateStream = new InflaterInputStream(bais);
        TTransport transport = new TIOStreamTransport(inflateStream);
        TCompactProtocol proto = new TCompactProtocol(transport);
        ScanResult result = new ScanResult();
        try {
            transport.open();
            result.read(proto);
        } catch (TException e) {
            throw new RuntimeException(e);
        } finally {
            transport.close();
        }
        List<TKeyValue> decoded = result.getResults();
        return fromThrift(decoded);
    }

}