org.apache.crunch.materialize.MaterializableIterable.java Source code

Introduction

Here is the source code for org.apache.crunch.materialize.MaterializableIterable.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.crunch.materialize;

import java.io.IOException;
import java.util.Iterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.crunch.CrunchRuntimeException;
import org.apache.crunch.Pipeline;
import org.apache.crunch.SourceTarget;
import org.apache.crunch.io.PathTarget;
import org.apache.crunch.io.ReadableSource;
import org.apache.crunch.io.impl.FileSourceImpl;
import org.apache.hadoop.fs.Path;

public class MaterializableIterable<E> implements Iterable<E> {

    private static final Log LOG = LogFactory.getLog(MaterializableIterable.class);

    private final Pipeline pipeline;
    private final ReadableSource<E> source;
    private Iterable<E> materialized;

    public MaterializableIterable(Pipeline pipeline, ReadableSource<E> source) {
        this.pipeline = pipeline;
        this.source = source;
        this.materialized = null;
    }

    public ReadableSource<E> getSource() {
        return source;
    }

    public boolean isSourceTarget() {
        return (source instanceof SourceTarget);
    }

    public Path getPath() {
        if (source instanceof FileSourceImpl) {
            return ((FileSourceImpl) source).getPath();
        }
        if (source instanceof PathTarget) {
            return ((PathTarget) source).getPath();
        }
        return null;
    }

    @Override
    public Iterator<E> iterator() {
        if (materialized == null) {
            pipeline.run();
            materialize();
        }
        return materialized.iterator();
    }

    public void materialize() {
        try {
            materialized = source.read(pipeline.getConfiguration());
        } catch (IOException e) {
            LOG.error("Could not materialize: " + source, e);
            throw new CrunchRuntimeException(e);
        }
    }
}