io.dstream.hadoop.TypeAwareWritable.java Source code

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Here is the source code for io.dstream.hadoop.TypeAwareWritable.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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
 *
 * 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 io.dstream.hadoop;

import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.nio.ByteBuffer;

import org.apache.commons.io.output.ByteArrayOutputStream;

/**
 * 
 */
@SuppressWarnings("unchecked")
public abstract class TypeAwareWritable<T> implements NewWritable<T> {

    protected T value;

    private byte valueType = NULL;

    private final ValueEncoder valueEncoder = new ValueEncoder();

    /**
     * 
     */
    public void setValue(T value) {
        this.value = value;
        this.determineValueType(value);
        this.valueType = this.valueEncoder.valueType;
    }

    /**
     * 
     */
    public T getValue() {
        return this.value;
    }

    /**
     * 
     */
    @Override
    public int hashCode() {
        int hashCode = 0;
        if (this.value != null) {
            hashCode = this.value.hashCode();
        }
        return hashCode;
    }

    /**
     * 
     */
    @Override
    public void write(DataOutput out) throws IOException {
        out.writeByte(this.valueType);
        if (this.valueType != NULL) {
            try {
                out.write(this.valueEncoder.valueBytes);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 
     */
    @Override
    public void readFields(DataInput in) throws IOException {
        this.valueType = in.readByte();
        switch (this.valueType) {
        case INTEGER:
            this.value = (T) Integer.valueOf(in.readInt());
            break;
        case LONG:
            this.value = (T) Long.valueOf(in.readLong());
            break;
        case NULL:
            this.value = null;
            break;
        case OBJECT:
            try {
                ObjectInputStream ois = new ObjectInputStream((DataInputStream) in);
                T value = (T) ois.readObject();
                this.value = (T) value;
            } catch (Exception e) {
                throw new IllegalStateException("Failed to deserialize value", e);
            }
            break;
        default:
            throw new IllegalStateException("Unsupported or unrecognized value type: " + this.valueType);
        }
    }

    /**
     * 
     */
    @Override
    public String toString() {
        if (this.value == null) {
            return null;
        } else {
            return this.value.toString();
        }
    }

    /**
     * NOTE: The below code is temporary and both conversion and ser/deser will be exposed through externally 
     * configurable framework!
     * 
     * @param value
     * @return
     */
    private void determineValueType(Object value) {
        if (value instanceof Integer) {
            this.valueEncoder.valueType = INTEGER;
            this.valueEncoder.valueBytes = ByteBuffer.allocate(4).putInt((Integer) value).array();
        } else if (value instanceof Long) {
            this.valueEncoder.valueType = LONG;
            this.valueEncoder.valueBytes = ByteBuffer.allocate(8).putLong((Long) value).array();
        } else if (value == null) {
            this.valueEncoder.valueType = NULL;
        } else {
            ObjectOutputStream oos = null;
            try {
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                oos = new ObjectOutputStream(bos);
                oos.writeObject(value);
                this.valueEncoder.valueType = OBJECT;
                this.valueEncoder.valueBytes = bos.toByteArray();
            } catch (Exception e) {
                throw new IllegalStateException("Failed to serialize value: " + value, e);
            } finally {
                try {
                    if (oos != null) {
                        oos.close();
                    }
                } catch (Exception e2) {
                    /*ignore*/}
            }
        }
    }

    private final static byte INTEGER = -128;
    private final static byte STRING = -127;
    private final static byte LONG = -126;
    private final static byte OBJECT = -125;
    private final static byte NULL = -124;

    /**
     */
    private class ValueEncoder {
        private byte valueType;
        private byte[] valueBytes;
    }
}