com.cloudera.dataflow.hadoop.NullWritableCoder.java Source code

Introduction

Here is the source code for com.cloudera.dataflow.hadoop.NullWritableCoder.java

Source

/*
 * Copyright (c) 2015, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. licenses this file to you 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
 *
 * This software 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.cloudera.dataflow.hadoop;

import java.io.InputStream;
import java.io.OutputStream;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.google.cloud.dataflow.sdk.coders.Coder;
import org.apache.hadoop.io.NullWritable;

public final class NullWritableCoder extends WritableCoder<NullWritable> {
    private static final long serialVersionUID = 1L;

    @JsonCreator
    public static NullWritableCoder of() {
        return INSTANCE;
    }

    private static final NullWritableCoder INSTANCE = new NullWritableCoder();

    private NullWritableCoder() {
        super(NullWritable.class);
    }

    @Override
    public void encode(NullWritable value, OutputStream outStream, Context context) {
        // nothing to write
    }

    @Override
    public NullWritable decode(InputStream inStream, Context context) {
        return NullWritable.get();
    }

    @Override
    public boolean consistentWithEquals() {
        return true;
    }

    /**
     * Returns true since registerByteSizeObserver() runs in constant time.
     */
    @Override
    public boolean isRegisterByteSizeObserverCheap(NullWritable value, Context context) {
        return true;
    }

    @Override
    protected long getEncodedElementByteSize(NullWritable value, Context context) {
        return 0;
    }

    @Override
    public void verifyDeterministic() throws Coder.NonDeterministicException {
        // NullWritableCoder is deterministic
    }
}