crunch-scrunch/src/it/scala/org/apache/crunch/scrunch/JoinTest.scala

/**
 * 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.scrunch

import org.apache.crunch.io.{From => from, To => to}
import org.apache.crunch.test.CrunchTestSupport

import org.scalatest.junit.JUnitSuite
import _root_.org.junit.Test

class JoinTest extends CrunchTestSupport with JUnitSuite {
  lazy val pipeline = Pipeline.mapReduce[CogroupTest](tempDir.getDefaultConfiguration)

  def wordCount(fileName: String) = {
    pipeline.read(from.textFile(fileName))
        .flatMap(_.toLowerCase.split("\\W+")).count
  }

  @Test def join {
    val shakespeare = tempDir.copyResourceFileName("shakes.txt")
    val maugham = tempDir.copyResourceFileName("maugham.txt")
    val output = tempDir.getFile("output")
    val filtered = wordCount(shakespeare).join(wordCount(maugham))
        .map((k, v) => (k, v._1 - v._2))
        .write(to.textFile(output.getAbsolutePath()))
        .filter((k, d) => d > 0).materialize
    assert(filtered.exists(_ == ("macbeth", 66)))
    pipeline.done
  }
}