org.canova.api.writable.Writable Maven / Gradle / Ivy
/*
*
* *
* * * Copyright 2015 Skymind,Inc.
* * *
* * * 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.canova.api.writable;
import java.io.DataOutput;
import java.io.DataInput;
import java.io.IOException;
import java.io.Serializable;
/**
* A serializable object which implements a simple, efficient, serialization
* protocol, based on {@link DataInput} and {@link DataOutput}.
*
* Any key or value type in the Hadoop Map-Reduce
* framework implements this interface.
*
* Implementations typically implement a static read(DataInput)
* method which constructs a new instance, calls {@link #readFields(DataInput)}
* and returns the instance.
*
* Example:
*
* public class MyWritable implements Writable {
* // 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 static MyWritable read(DataInput in) throws IOException {
* MyWritable w = new MyWritable();
* w.readFields(in);
* return w;
* }
* }
*
*/
public interface Writable extends Serializable {
/**
* Serialize the fields of this object to out.
*
* @param out DataOuput to serialize this object into.
* @throws IOException
*/
void write(DataOutput out) throws IOException;
/**
* Deserialize the fields of this object from in.
*
* For efficiency, implementations should attempt to re-use storage in the
* existing object where possible.
*
* @param in DataInput to deseriablize this object from.
* @throws IOException
*/
void readFields(DataInput in) throws IOException;
/** Convert Writable to double. Whether this is supported depends on the specific writable. */
double toDouble();
/** Convert Writable to float. Whether this is supported depends on the specific writable. */
float toFloat();
/** Convert Writable to int. Whether this is supported depends on the specific writable. */
int toInt();
/** Convert Writable to long. Whether this is supported depends on the specific writable. */
long toLong();
}