com.hotels.plunger.TupleListTap Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of nexusreleasetest Show documentation
Framework to simplify testing Cascading applications
The newest version!
/**
 * Copyright 2015 Expedia Inc.
 *
 * 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.hotels.plunger;

import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.UUID;

import cascading.flow.FlowProcess;
import cascading.pipe.Pipe;
import cascading.tap.Tap;
import cascading.tuple.Fields;
import cascading.tuple.Tuple;
import cascading.tuple.TupleEntryCollector;
import cascading.tuple.TupleEntryIterator;

/**
 * A {@link Tap} implementation for sourcing {@link Tuple} instances in a unit testing environment.
 */
public class TupleListTap extends Tap, List> {

  private static final long serialVersionUID = 1L;

  private final String id;
  private final long lastModified;
  private final Iterator input;

  /**
   * Constructs a tap that can provided the declared {@link Tuple Tuples} into a {@link Pipe}.
   */
  TupleListTap(Fields fields, Iterable input) {
    super(new TupleScheme(fields));
    this.input = input.iterator();
    id = getClass().getSimpleName() + ":" + UUID.randomUUID().toString();
    lastModified = System.currentTimeMillis();
  }

  /** {@inheritDoc} */
  @Override
  public String getIdentifier() {
    return id;
  }

  /**
   * {@inheritDoc}
   * 
   * Returned type is a {@link ListTupleEntryIterator}.
   */
  @Override
  public TupleEntryIterator openForRead(FlowProcess flowProcess, Iterator input) throws IOException {
    return new ListTupleEntryIterator(getSourceFields(), this.input);
  }

  /**
   * Always throws {@link UnsupportedOperationException} - this is a tap not a sink.
   * 
   * @throws UnsupportedOperationException always.
   */
  @Override
  public TupleEntryCollector openForWrite(FlowProcess flowProcess, List output) throws IOException {
    throw new UnsupportedOperationException("cannot write to a " + getClass().getSimpleName());
  }

  /** {@inheritDoc} */
  @Override
  public boolean createResource(Properties conf) throws IOException {
    return false;
  }

  /** {@inheritDoc} */
  @Override
  public boolean deleteResource(Properties conf) throws IOException {
    return false;
  }

  /** {@inheritDoc} */
  @Override
  public boolean resourceExists(Properties conf) throws IOException {
    return true;
  }

  /** {@inheritDoc} */
  @Override
  public long getModifiedTime(Properties conf) throws IOException {
    return lastModified;
  }

  /** Returns the tuples that are delivered by this tap. */
  Iterator getInput() {
    return input;
  }

}