Example usage for java.util SortedMap hashCode

Introduction

In this page you can find the example usage for java.util SortedMap hashCode.

Prototype

int hashCode();

Source Link

Document

Returns the hash code value for this map.

Usage

From source file:com.google.gwt.emultest.java.util.TreeMapTest.java

/**
 * Test method for 'java.util.Map.put(Object, Object)'. This test shows some
 * bad behavior of the TreeMap class before JDK 7. A mapping with null key can
 * be put in but several methods are are unusable afterward.
 *
 * A SortedMap with natural ordering (no comparator) is supposed to throw a
 * null pointer exception if a null keys are "not supported". For a natural
 * ordered TreeMap before JDK 7, a null pointer exception is not thrown. But,
 * the map is left in a state where any other key based methods result in a
 * null pointer exception.//from  w  w w.  j  ava  2  s.co m
 *
 * @see java.util.Map#put(Object, Object)
 */
public void testPut_nullKey() {
    K[] keys = getSortedKeys();
    V[] values = getSortedValues();
    SortedMap<K, V> sortedMap = createNavigableMap();

    if (useNullKey()) {
        assertNull(sortedMap.put(null, values[0]));
        assertTrue(sortedMap.containsValue(values[0]));

        // the map methods the continue to function
        sortedMap.containsValue(null);
        sortedMap.containsValue(values[0]);
        sortedMap.entrySet();
        sortedMap.equals(createMap());
        sortedMap.hashCode();
        sortedMap.isEmpty();
        sortedMap.keySet();
        sortedMap.putAll(createMap());
        sortedMap.size();
        sortedMap.values();

        // all of the sorted map methods still function
        sortedMap.comparator();
        sortedMap.firstKey();
        sortedMap.lastKey();
        sortedMap.subMap(getLessThanMinimumKey(), getGreaterThanMaximumKey());
        sortedMap.headMap(getLessThanMinimumKey());
        sortedMap.tailMap(getLessThanMinimumKey());
    } else if (TestUtils.getJdkVersion() > 6) {
        // nulls are rejected immediately and don't poison the map anymore
        try {
            assertNull(sortedMap.put(null, values[0]));
            fail("should have thrown");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            assertNull(sortedMap.put(null, values[1]));
            fail("expected exception adding second null");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.containsKey(null);
            fail("expected exception on containsKey(null)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        sortedMap.containsKey(keys[0]);
        try {
            sortedMap.get(null);
            fail("expected exception on get(null)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        sortedMap.get(keys[0]);
        try {
            sortedMap.remove(null);
        } catch (NullPointerException e) {
            // expected
        }
        sortedMap.remove(keys[0]);
    } else {
        // before JDK 7, nulls poisoned the map
        try {
            assertNull(sortedMap.put(null, values[0]));
            // note: first null added is not required to throw NPE since no
            // comparisons are needed
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            assertNull(sortedMap.put(null, values[1]));
            fail("expected exception adding second null");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.containsKey(null);
            fail("expected exception on containsKey(null)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.containsKey(keys[0]);
            fail("expected exception on contains(key)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.get(null);
            fail("expected exception on get(null)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.get(keys[0]);
            fail("expected exception on get(key)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.remove(null);
            fail("expected exception on remove(null)");
        } catch (NullPointerException e) {
            // expected outcome
        }
        try {
            sortedMap.remove(keys[0]);
            fail("expected exception on remove(key)");
        } catch (NullPointerException e) {
            // expected outcome
        }
    }
}

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