org.apache.nutch.util.GenericWritableConfigurable.java Source code

Introduction

Here is the source code for org.apache.nutch.util.GenericWritableConfigurable.java

Source

/*
 * 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 org.apache.nutch.util;

import java.io.DataInput;
import java.io.IOException;

import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.GenericWritable;
import org.apache.hadoop.io.Writable;

/**
 * A generic Writable wrapper that can inject Configuration to
 * {@link Configurable}s
 */
public abstract class GenericWritableConfigurable extends GenericWritable implements Configurable {

    private Configuration conf;

    public Configuration getConf() {
        return conf;
    }

    public void setConf(Configuration conf) {
        this.conf = conf;
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        byte type = in.readByte();
        Class<?> clazz = getTypes()[type];
        try {
            set((Writable) clazz.newInstance());
        } catch (Exception e) {
            e.printStackTrace();
            throw new IOException("Cannot initialize the class: " + clazz);
        }
        Writable w = get();
        if (w instanceof Configurable)
            ((Configurable) w).setConf(conf);
        w.readFields(in);
    }

}