com.conversantmedia.mapreduce.tool.annotation.handler.NamedOutputAnnotationHandler.java Source code

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Here is the source code for com.conversantmedia.mapreduce.tool.annotation.handler.NamedOutputAnnotationHandler.java

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package com.conversantmedia.mapreduce.tool.annotation.handler;

/*
 * #%L
 * Mara Core framework
 * ~~
 * Copyright (C) 2015 Conversant
 * ~~
 * 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.
 * #L%
 */

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.HashSet;
import java.util.Set;

import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.output.MultipleOutputs;
import org.springframework.stereotype.Service;

import com.conversantmedia.mapreduce.tool.ToolException;
import com.conversantmedia.mapreduce.tool.annotation.KeyValue;
import com.conversantmedia.mapreduce.tool.annotation.NamedOutput;

/**
 * Sets up a multiple output.
 *
 */
@Service
public class NamedOutputAnnotationHandler extends AnnotationHandlerBase {

    private final Set<String> configured = new HashSet<>();

    @Override
    public boolean accept(Annotation annotation) throws ToolException {
        return annotation.annotationType() == NamedOutput.class;
    }

    @Override
    public void process(Annotation annotation, Job job, Object target) throws ToolException {
        NamedOutput namedOut = (NamedOutput) annotation;
        KeyValue kv = namedOut.type();

        // If this is a MultipleOutputs member we're annotating, see if we can't
        // get the key/value from the parameters if there are any.
        Pair<Type, Type> kvTypePair = getGenericTypeParams(target);

        Class<?> keyClass = kv.key();
        if (keyClass == void.class) {
            if (kvTypePair != null) {
                keyClass = (Class<?>) kvTypePair.getKey();
            } else {
                // fall back on job output key class
                keyClass = job.getOutputKeyClass();
            }
        }

        Class<?> valueClass = kv.value();
        if (valueClass == void.class) {
            if (kvTypePair != null) {
                valueClass = (Class<?>) kvTypePair.getValue();
            } else {
                valueClass = job.getOutputValueClass();
            }
        }

        String[] names = getNames(namedOut);
        for (String name : names) {
            name = (String) evaluateExpression(name);
            if (!configured.contains(name)) {
                MultipleOutputs.addNamedOutput(job, name, namedOut.format(), keyClass, valueClass);
                MultipleOutputs.setCountersEnabled(job, namedOut.countersEnabled());
                configured.add(name);
            }
        }
    }

    public String[] getNames(NamedOutput namedOut) {
        String[] names = new String[1];
        if (namedOut.value().length > 1) {
            // Must be specified as @NamedOutput({"name1","name2"})
            names = namedOut.value();
        } else if (namedOut.name().length > 1) {
            // Must be specified as @NamedOutput(name={"name1","name2"},..)
            names = namedOut.name();
        } else {
            names[0] = namedOut.value()[0].equals("default") ? namedOut.name()[0] : namedOut.value()[0];
        }
        return names;
    }

    /**
     * If this is a multiple output we're annotating, see if there are type parameters to
     * use for the key/value classes.
     * 
     * @param target   object to reflect for type params
     * @return         the key/value type parameters
     */
    protected Pair<Type, Type> getGenericTypeParams(Object target) {
        Pair<Type, Type> kvTypePair = null;
        if (target instanceof Field) {
            Field field = (Field) target;
            if (field.getType() == MultipleOutputs.class) {
                Type genericType = field.getGenericType();
                if (genericType instanceof ParameterizedType) {
                    Type[] keyValueTypes = ((ParameterizedType) genericType).getActualTypeArguments();
                    if (keyValueTypes != null && keyValueTypes.length == 2) {
                        kvTypePair = new ImmutablePair<>(keyValueTypes[0], keyValueTypes[1]);
                    }
                }
            }
        }
        return kvTypePair;
    }

}