com.ikanow.aleph2.analytics.hadoop.assets.ObjectNodeWritableComparable.java Source code

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Here is the source code for com.ikanow.aleph2.analytics.hadoop.assets.ObjectNodeWritableComparable.java

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/*******************************************************************************
 * Copyright 2015, The IKANOW Open Source Project.
 *
 * 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.ikanow.aleph2.analytics.hadoop.assets;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Optional;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.ikanow.aleph2.data_model.utils.BeanTemplateUtils;

/** Object node wrapper that is also hadoop Writable
 * @author Alex
 */
public class ObjectNodeWritableComparable implements WritableComparable<Object> {

    protected static ObjectMapper _mapper = BeanTemplateUtils.configureMapper(Optional.empty());

    private ObjectNode _object_node;

    /** Returns the wrapped JSON object
     * @return
     */
    public JsonNode get() {
        return _object_node;
    }

    /** System c'tor
     */
    public ObjectNodeWritableComparable() {
    }

    /** User c'tor
     * @param object_node
     */
    public ObjectNodeWritableComparable(final ObjectNode object_node) {
        _object_node = object_node;
    }

    /* (non-Javadoc)
     * @see org.apache.hadoop.io.Writable#write(java.io.DataOutput)
     */
    @Override
    public void write(DataOutput out) throws IOException {
        final Text text = new Text();
        text.set(_object_node.toString());

        text.write(out);
    }

    /* (non-Javadoc)
     * @see org.apache.hadoop.io.Writable#readFields(java.io.DataInput)
     */
    @Override
    public void readFields(DataInput in) throws IOException {
        final Text text = new Text();
        text.readFields(in);

        _object_node = (ObjectNode) _mapper.readTree(text.toString()); //(object node by construction)
    }

    @Override
    public String toString() {
        return _object_node.toString();
    }

    /* (non-Javadoc)
     * @see java.lang.Comparable#compareTo(java.lang.Object)
     */
    @Override
    public int compareTo(Object o) {
        // Should never be called, if it is then just use the JSON representation
        return toString().compareTo(o.toString());
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        return _object_node.hashCode();
    }

    public static class Comparator extends Text.Comparator {
        //(nothing to do, just use the defaults - this object is transmitted as Text binary)
    }
}