/*
    * 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.giraph.edge;
  
  import com.google.common.collect.Lists;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.io.NullWritable;
  import org.junit.Before;
  import org.junit.Test;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  
  import static org.apache.giraph.graph.TestVertexAndEdges.instantiateOutEdges;
  import static org.junit.Assert.assertEquals;
  
  /**
   * Tests {@link OutEdges} implementations with null edge values.
   */
  public class TestNullValueEdges {
    /** {@link OutEdges} classes to be tested. */
    private Collection<Class<? extends MutableOutEdges>>
        edgesClasses = Lists.newArrayList();
  
    @Before
    public void setUp() {
      edgesClasses.add(LongNullArrayEdges.class);
      edgesClasses.add(LongNullHashSetEdges.class);
    }
  
    @Test
    public void testEdges() {
      for (Class<? extends OutEdges> edgesClass : edgesClasses) {
        testEdgesClass(edgesClass);
      }
    }
  
    private void testEdgesClass(
        Class<? extends OutEdges> edgesClass) {
      OutEdges<LongWritable, NullWritable> edges =
          (OutEdges<LongWritable, NullWritable>)
              instantiateOutEdges(edgesClass);
  
      List<Edge<LongWritable, NullWritable>> initialEdges = Lists.newArrayList(
          EdgeFactory.create(new LongWritable(1)),
          EdgeFactory.create(new LongWritable(2)),
          EdgeFactory.create(new LongWritable(3)));
  
      edges.initialize(initialEdges);
      assertEquals(3, edges.size());
  
      edges.add(EdgeFactory.createReusable(new LongWritable(4)));
      assertEquals(4, edges.size());
  
      edges.remove(new LongWritable(2));
      assertEquals(3, edges.size());
    }
  
    /**
     * Test in-place edge mutations via the iterable returned by {@link
     * org.apache.giraph.graph.Vertex#getMutableEdges()}.
     */
    @Test
    public void testMutateEdges() {
      for (Class<? extends MutableOutEdges> edgesClass : edgesClasses) {
        testMutateEdgesClass(edgesClass);
      }
    }
  
    private void testMutateEdgesClass(
        Class<? extends MutableOutEdges> edgesClass) {
      MutableOutEdges<LongWritable, NullWritable> edges =
         (MutableOutEdges<LongWritable, NullWritable>)
             instantiateOutEdges(edgesClass);
  
      edges.initialize();
  
      // Add 10 edges with id i, for i = 0..9
      for (int i = 0; i < 10; ++i) {
        edges.add(EdgeFactory.create(new LongWritable(i)));
      }
  
     // Use the mutable iterator to remove edges with even id
     Iterator<MutableEdge<LongWritable, NullWritable>> edgeIt =
         edges.mutableIterator();
     while (edgeIt.hasNext()) {
       if (edgeIt.next().getTargetVertexId().get() % 2 == 0) {
         edgeIt.remove();
       }
     }
 
     // We should now have 5 edges
     assertEquals(5, edges.size());
     // The edge ids should be all odd
     for (Edge<LongWritable, NullWritable> edge : edges) {
       assertEquals(1, edge.getTargetVertexId().get() % 2);
     }
   }
 }