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/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://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.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

package org.datavec.api.io;


import org.datavec.api.writable.Writable;

/**
 * A {@link Writable} which is also {@link Comparable}.
 *
 * WritableComparables can be compared to each other, typically 
 * via Comparators. Any type which is to be used as a 
 * key in the Hadoop Map-Reduce framework should implement this
 * interface.
 *
 * Example:
 * 
 *     public class MyWritableComparable implements WritableComparable {
 *       // Some data
 *       private int counter;
 *       private long timestamp;
 *
 *       public void write(DataOutput out) throws IOException {
 *         out.writeInt(counter);
 *         out.writeLong(timestamp);
 *       }
 *
 *       public void readFields(DataInput in) throws IOException {
 *         counter = in.readInt();
 *         timestamp = in.readLong();
 *       }
 *
 *       public int compareTo(MyWritableComparable w) {
 *         int thisValue = this.value;
 *         int thatValue = ((IntWritable)o).value;
 *         return (thisValue < thatValue ? -1 : (thisValue==thatValue ? 0 : 1));
 *       }
 *     }
 * 

 */
public interface WritableComparable extends Writable, Comparable {
}