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Java example source code file (MapsTransformValuesTest.java)

This example Java source code file (MapsTransformValuesTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

annotation, boolean, collection, function, gwtcompatible, integer, iterator, map, mapinterfacetest, mapstransformvaluestest, override, runtimeexception, set, string, unsupportedoperationexception, util

The MapsTransformValuesTest.java Java example source code

/*
 * Copyright (C) 2008 The Guava Authors
 *
 * 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.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.collect.testing.MapInterfaceTest;

import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.annotation.Nullable;

/**
 * Tests for {@link Maps#transformValues}.
 *
 * @author Isaac Shum
 */
@GwtCompatible
public class MapsTransformValuesTest extends MapInterfaceTest<String, String> {

  /**
   * Constructor that assigns {@code supportsIteratorRemove} the same value as
   * {@code supportsRemove}.
   */
  protected MapsTransformValuesTest(
      boolean allowsNullKeys,
      boolean allowsNullValues,
      boolean supportsPut,
      boolean supportsRemove,
      boolean supportsClear) {
    super(allowsNullKeys, allowsNullValues, supportsPut, supportsRemove,
        supportsClear, supportsRemove);
  }

  public MapsTransformValuesTest() {
    super(false, true, false, true, true);
  }

  protected Map<String, String> makeEmptyMap() {
    return Maps.transformValues(Maps.<String, String>newHashMap(),
        Functions.<String>identity());
  }

  @Override
  protected Map<String, String> makePopulatedMap() {
    Map<String, Integer> underlying = Maps.newHashMap();
    underlying.put("a", 1);
    underlying.put("b", 2);
    underlying.put("c", 3);
    return Maps.transformValues(underlying, Functions.toStringFunction());
  }

  @Override protected String getKeyNotInPopulatedMap()
      throws UnsupportedOperationException {
    return "z";
  }

  @Override protected String getValueNotInPopulatedMap()
      throws UnsupportedOperationException {
    return "26";
  }

  /** Helper assertion comparing two maps */
  private void assertMapsEqual(Map<?, ?> expected, Map map) {
    assertEquals(expected, map);
    assertEquals(expected.hashCode(), map.hashCode());
    assertEquals(expected.entrySet(), map.entrySet());

    // Assert that expectedValues > mapValues and that
    // mapValues > expectedValues; i.e. that expectedValues == mapValues.
    Collection<?> expectedValues = expected.values();
    Collection<?> mapValues = map.values();
    assertEquals(expectedValues.size(), mapValues.size());
    assertTrue(expectedValues.containsAll(mapValues));
    assertTrue(mapValues.containsAll(expectedValues));
  }

  public void testTransformEmptyMapEquality() {
    Map<String, String> map = Maps.transformValues(
        ImmutableMap.<String, Integer>of(), Functions.toStringFunction());
    assertMapsEqual(Maps.newHashMap(), map);
  }

  public void testTransformSingletonMapEquality() {
    Map<String, String> map = Maps.transformValues(
        ImmutableMap.of("a", 1), Functions.toStringFunction());
    Map<String, String> expected = ImmutableMap.of("a", "1");
    assertMapsEqual(expected, map);
    assertEquals(expected.get("a"), map.get("a"));
  }

  public void testTransformIdentityFunctionEquality() {
    Map<String, Integer> underlying = ImmutableMap.of("a", 1);
    Map<String, Integer> map = Maps.transformValues(
        underlying, Functions.<Integer>identity());
    assertMapsEqual(underlying, map);
  }

  public void testTransformPutEntryIsUnsupported() {
    Map<String, String> map = Maps.transformValues(
        ImmutableMap.of("a", 1), Functions.toStringFunction());
    try {
      map.put("b", "2");
      fail();
    } catch (UnsupportedOperationException expected) {
    }

    try {
      map.putAll(ImmutableMap.of("b", "2"));
      fail();
    } catch (UnsupportedOperationException expected) {
    }

    try {
      map.entrySet().iterator().next().setValue("one");
      fail();
    } catch (UnsupportedOperationException expected) {
    }
  }

  public void testTransformRemoveEntry() {
    Map<String, Integer> underlying = Maps.newHashMap();
    underlying.put("a", 1);
    Map<String, String> map
        = Maps.transformValues(underlying, Functions.toStringFunction());
    assertEquals("1", map.remove("a"));
    assertNull(map.remove("b"));
  }

  public void testTransformEqualityOfMapsWithNullValues() {
    Map<String, String> underlying = Maps.newHashMap();
    underlying.put("a", null);
    underlying.put("b", "");

    Map<String, Boolean> map = Maps.transformValues(underlying,
        new Function<String, Boolean>() {
          @Override
          public Boolean apply(@Nullable String from) {
            return from == null;
          }
        }
    );
    Map<String, Boolean> expected = ImmutableMap.of("a", true, "b", false);
    assertMapsEqual(expected, map);
    assertEquals(expected.get("a"), map.get("a"));
    assertEquals(expected.containsKey("a"), map.containsKey("a"));
    assertEquals(expected.get("b"), map.get("b"));
    assertEquals(expected.containsKey("b"), map.containsKey("b"));
    assertEquals(expected.get("c"), map.get("c"));
    assertEquals(expected.containsKey("c"), map.containsKey("c"));
  }

  public void testTransformReflectsUnderlyingMap() {
    Map<String, Integer> underlying = Maps.newHashMap();
    underlying.put("a", 1);
    underlying.put("b", 2);
    underlying.put("c", 3);
    Map<String, String> map
        = Maps.transformValues(underlying, Functions.toStringFunction());
    assertEquals(underlying.size(), map.size());

    underlying.put("d", 4);
    assertEquals(underlying.size(), map.size());
    assertEquals("4", map.get("d"));

    underlying.remove("c");
    assertEquals(underlying.size(), map.size());
    assertFalse(map.containsKey("c"));

    underlying.clear();
    assertEquals(underlying.size(), map.size());
  }

  public void testTransformChangesAreReflectedInUnderlyingMap() {
    Map<String, Integer> underlying = Maps.newLinkedHashMap();
    underlying.put("a", 1);
    underlying.put("b", 2);
    underlying.put("c", 3);
    underlying.put("d", 4);
    underlying.put("e", 5);
    underlying.put("f", 6);
    underlying.put("g", 7);
    Map<String, String> map
        = Maps.transformValues(underlying, Functions.toStringFunction());

    map.remove("a");
    assertFalse(underlying.containsKey("a"));

    Set<String> keys = map.keySet();
    keys.remove("b");
    assertFalse(underlying.containsKey("b"));

    Iterator<String> keyIterator = keys.iterator();
    keyIterator.next();
    keyIterator.remove();
    assertFalse(underlying.containsKey("c"));

    Collection<String> values = map.values();
    values.remove("4");
    assertFalse(underlying.containsKey("d"));

    Iterator<String> valueIterator = values.iterator();
    valueIterator.next();
    valueIterator.remove();
    assertFalse(underlying.containsKey("e"));

    Set<Map.Entry entries = map.entrySet();
    Map.Entry<String, String> firstEntry = entries.iterator().next();
    entries.remove(firstEntry);
    assertFalse(underlying.containsKey("f"));

    Iterator<Map.Entry entryIterator = entries.iterator();
    entryIterator.next();
    entryIterator.remove();
    assertFalse(underlying.containsKey("g"));

    assertTrue(underlying.isEmpty());
    assertTrue(map.isEmpty());
    assertTrue(keys.isEmpty());
    assertTrue(values.isEmpty());
    assertTrue(entries.isEmpty());
  }

  public void testTransformEquals() {
    Map<String, Integer> underlying = ImmutableMap.of("a", 0, "b", 1, "c", 2);
    Map<String, Integer> expected
        = Maps.transformValues(underlying, Functions.<Integer>identity());

    assertMapsEqual(expected, expected);

    Map<String, Integer> equalToUnderlying = Maps.newTreeMap();
    equalToUnderlying.putAll(underlying);
    Map<String, Integer> map = Maps.transformValues(
        equalToUnderlying, Functions.<Integer>identity());
    assertMapsEqual(expected, map);

    map = Maps.transformValues(ImmutableMap.of("a", 1, "b", 2, "c", 3),
        new Function<Integer, Integer>() {
          @Override
          public Integer apply(Integer from) {
            return from - 1;
          }
        }
    );
    assertMapsEqual(expected, map);
  }

  public void testTransformEntrySetContains() {
    Map<String, Boolean> underlying = Maps.newHashMap();
    underlying.put("a", null);
    underlying.put("b", true);
    underlying.put(null, true);

    Map<String, Boolean> map = Maps.transformValues(
        underlying, new Function<Boolean, Boolean>() {
          @Override
          public Boolean apply(@Nullable Boolean from) {
            return (from == null) ? true : null;
          }
        }
    );

    Set<Map.Entry entries = map.entrySet();
    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.immutableEntry("b", (Boolean) null)));
    assertTrue(entries.contains(
        Maps.immutableEntry((String) null, (Boolean) null)));

    assertFalse(entries.contains(Maps.immutableEntry("c", (Boolean) null)));
    assertFalse(entries.contains(Maps.immutableEntry((String) null, true)));
  }

  @Override public void testKeySetRemoveAllNullFromEmpty() {
    try {
      super.testKeySetRemoveAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's HashMap.keySet().removeAll(null) doesn't throws NPE.
    }
  }

  @Override public void testEntrySetRemoveAllNullFromEmpty() {
    try {
      super.testEntrySetRemoveAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's HashMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }
}

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