content: /*
   * 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.beam.runners.dataflow.worker.util.common;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Iterator;
  import java.util.List;
  import org.apache.beam.sdk.util.common.Reiterator;
  import org.junit.Assert;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Tests for {@link TaggedReiteratorList}. */
  @RunWith(JUnit4.class)
  @SuppressWarnings({"keyfor"})
  public class TaggedReiteratorListTest {
  
    @Test
    public void testSingleIterator() {
      TaggedReiteratorList iter = create(new String[] {"a", "b", "c"});
      assertEquals(iter.get(0), "a", "b", "c");
      assertEquals(iter.get(0), "a", "b", "c");
      assertEquals(iter.get(1) /*empty*/);
      assertEquals(iter.get(0), "a", "b", "c");
    }
  
    @Test
    public void testSequentialAccess() {
      TaggedReiteratorList iter = create(3, new String[] {"a", "b", "c"});
      for (int i = 0; i < 2; i++) {
        assertEquals(iter.get(0), "a0", "b0", "c0");
        assertEquals(iter.get(1), "a1", "b1", "c1");
        assertEquals(iter.get(2), "a2", "b2", "c2");
      }
      for (int i = 0; i < 2; i++) {
        assertEquals(iter.get(2), "a2", "b2", "c2");
        assertEquals(iter.get(1), "a1", "b1", "c1");
        assertEquals(iter.get(0), "a0", "b0", "c0");
      }
    }
  
    @Test
    public void testRandomAccess() {
      TaggedReiteratorList iter = create(6, new String[] {"a", "b"});
      assertEquals(iter.get(3), "a3", "b3");
      assertEquals(iter.get(1), "a1", "b1");
      assertEquals(iter.get(5), "a5", "b5");
      assertEquals(iter.get(0), "a0", "b0");
      assertEquals(iter.get(4), "a4", "b4");
      assertEquals(iter.get(4), "a4", "b4");
      assertEquals(iter.get(1), "a1", "b1");
    }
  
    @Test
    public void testPartialIteration() {
      TaggedReiteratorList iter = create(6, new String[] {"a", "b", "c"});
      Iterator<?> get0 = iter.get(0);
      Iterator<?> get1 = iter.get(1);
      Iterator<?> get3 = iter.get(3);
      assertEquals(asList(get0, 1), "a0");
      assertEquals(asList(get1, 2), "a1", "b1");
      assertEquals(asList(get3, 3), "a3", "b3", "c3");
      Iterator<?> get2 = iter.get(2);
      Iterator<?> get0Again = iter.get(0);
      assertEquals(asList(get0, 1), "b0");
      assertEquals(get2, "a2", "b2", "c2");
      assertEquals(get0Again, "a0", "b0", "c0");
      assertEquals(asList(get0), "c0");
      Iterator<?> get4 = iter.get(4);
      assertEquals(get4, "a4", "b4", "c4");
      assertEquals(get4 /*empty*/);
      assertEquals(iter.get(4), "a4", "b4", "c4");
    }
  
    @Test
    public void testNextIteration() {
      TaggedReiteratorList iter = create(2, new String[] {"a", "b", "c"});
      Reiterator<?> get0 = iter.get(0);
      assertEquals(get0, "a0", "b0", "c0");
      Iterator<?> get1 = iter.get(1);
      Assert.assertEquals("a1", get1.next());
      assertEquals(get0.copy() /*empty*/);
      Assert.assertEquals("b1", get1.next());
      assertEquals(iter.get(1), "a1", "b1", "c1");
    }
  
    @Test
    public void testEmpties() {
      TaggedReiteratorList iter =
          create(
              new String[] {},
              new String[] {"a", "b", "c"},
              new String[] {},
              new String[] {},
              new String[] {"d"});
      assertEquals(iter.get(2) /*empty*/);
      assertEquals(iter.get(1), "a", "b", "c");
      assertEquals(iter.get(2) /*empty*/);
      assertEquals(iter.get(0) /*empty*/);
      assertEquals(iter.get(2) /*empty*/);
      assertEquals(iter.get(4), "d");
      assertEquals(iter.get(3) /*empty*/);
    }
  
    /////////////////////////////////////////////////////////////////////////////
    // Helpers
  
    private TaggedReiteratorList create(String[]... values) {
      ArrayList<TaggedValue> taggedValues = new ArrayList<>();
      for (int tag = 0; tag < values.length; tag++) {
        for (String value : values[tag]) {
          taggedValues.add(new TaggedValue(tag, value));
        }
      }
      return new TaggedReiteratorList(
          new TestReiterator(taggedValues.toArray(new TaggedValue[0])), new TaggedValueExtractor());
    }
  
    private TaggedReiteratorList create(int repeat, String... values) {
      ArrayList<TaggedValue> taggedValues = new ArrayList<>();
      for (int tag = 0; tag < repeat; tag++) {
        for (String value : values) {
          taggedValues.add(new TaggedValue(tag, value + tag));
        }
      }
      return new TaggedReiteratorList(
          new TestReiterator(taggedValues.toArray(new TaggedValue[0])), new TaggedValueExtractor());
    }
  
    private <T> List<T> asList(Iterator<T> iter) {
      return asList(iter, Integer.MAX_VALUE);
    }
  
    private <T> List<T> asList(Iterator<T> iter, int limit) {
      List<T> list = new ArrayList<>();
      for (int i = 0; i < limit && iter.hasNext(); i++) {
        list.add(iter.next());
      }
      return list;
    }
  
    private void assertEquals(Iterator<?> actual, Object... expected) {
      assertEquals(asList(actual), expected);
    }
  
    private void assertEquals(List<?> actual, Object... expected) {
      Assert.assertEquals(Arrays.asList(expected), actual);
    }
  
    private static class TestReiterator implements Reiterator<TaggedValue> {
      private final TaggedValue[] values;
      private int pos = 0;
  
      public TestReiterator(TaggedValue... values) {
        this(values, 0);
      }
  
      private TestReiterator(TaggedValue[] values, int pos) {
        this.values = values;
        this.pos = pos;
      }
  
      @Override
      public boolean hasNext() {
        return pos < values.length;
      }
  
      @Override
      public TaggedValue next() {
        return values[pos++];
      }
  
      @Override
      public void remove() {
        throw new IllegalArgumentException();
      }
  
      @Override
      public TestReiterator copy() {
        return new TestReiterator(values, pos);
      }
    }
  
    private static class TaggedValueExtractor
        implements TaggedReiteratorList.TagExtractor<TaggedValue> {
      @Override
      public int getTag(TaggedValue elem) {
        return elem.tag;
      }
  
      @Override
      public String getValue(TaggedValue elem) {
        return elem.value;
      }
    }
  
    private static class TaggedValue {
      public final int tag;
      public final String value;
  
      public TaggedValue(int tag, String value) {
        this.tag = tag;
        this.value = value;
      }
    }
  }
  