jsr166-tests/src/test/java/jsr166/ConcurrentHashMapTest.java - platform/libcore - Git at Google

 /*
  * Written by Doug Lea with assistance from members of JCP JSR-166
  * Expert Group and released to the public domain, as explained at
  * http://creativecommons.org/publicdomain/zero/1.0/
  * Other contributors include Andrew Wright, Jeffrey Hayes,
  * Pat Fisher, Mike Judd.
  */

 package jsr166;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;

 import junit.framework.Test;
 import junit.framework.TestSuite;

 public class ConcurrentHashMapTest extends JSR166TestCase {
     // android-note: Removed because the CTS runner does a bad job of
     // retrying tests that have suite() declarations.
     //
     // public static void main(String[] args) {
     //     main(suite(), args);
     // }
     // public static Test suite() {
     //     return new TestSuite(ConcurrentHashMapTest.class);
     // }

     /**
      * Returns a new map from Integers 1-5 to Strings "A"-"E".
      */
     private static ConcurrentHashMap<Integer, String> map5() {
         ConcurrentHashMap map = new ConcurrentHashMap<Integer, String>(5);
         assertTrue(map.isEmpty());
         map.put(one, "A");
         map.put(two, "B");
         map.put(three, "C");
         map.put(four, "D");
         map.put(five, "E");
         assertFalse(map.isEmpty());
         assertEquals(5, map.size());
         return map;
     }

     /** Re-implement Integer.compare for old java versions */
     static int compare(int x, int y) {
         return (x < y) ? -1 : (x > y) ? 1 : 0;
     }

     // classes for testing Comparable fallbacks
     static class BI implements Comparable<BI> {
         private final int value;
         BI(int value) { this.value = value; }
         public int compareTo(BI other) {
             return compare(value, other.value);
         }
         public boolean equals(Object x) {
             return (x instanceof BI) && ((BI)x).value == value;
         }
         public int hashCode() { return 42; }
     }
     static class CI extends BI { CI(int value) { super(value); } }
     static class DI extends BI { DI(int value) { super(value); } }

     static class BS implements Comparable<BS> {
         private final String value;
         BS(String value) { this.value = value; }
         public int compareTo(BS other) {
             return value.compareTo(other.value);
         }
         public boolean equals(Object x) {
             return (x instanceof BS) && value.equals(((BS)x).value);
         }
         public int hashCode() { return 42; }
     }

     static class LexicographicList<E extends Comparable<E>> extends ArrayList<E>
         implements Comparable<LexicographicList<E>> {
         LexicographicList(Collection<E> c) { super(c); }
         LexicographicList(E e) { super(Collections.singleton(e)); }
         public int compareTo(LexicographicList<E> other) {
             int common = Math.min(size(), other.size());
             int r = 0;
             for (int i = 0; i < common; i++) {
                 if ((r = get(i).compareTo(other.get(i))) != 0)
                     break;
             }
             if (r == 0)
                 r = compare(size(), other.size());
             return r;
         }
         private static final long serialVersionUID = 0;
     }

     static class CollidingObject {
         final String value;
         CollidingObject(final String value) { this.value = value; }
         public int hashCode() { return this.value.hashCode() & 1; }
         public boolean equals(final Object obj) {
             return (obj instanceof CollidingObject) && ((CollidingObject)obj).value.equals(value);
         }
     }

     static class ComparableCollidingObject extends CollidingObject implements Comparable<ComparableCollidingObject> {
         ComparableCollidingObject(final String value) { super(value); }
         public int compareTo(final ComparableCollidingObject o) {
             return value.compareTo(o.value);
         }
     }

     /**
      * Inserted elements that are subclasses of the same Comparable
      * class are found.
      */
     public void testComparableFamily() {
         int size = 500;         // makes measured test run time -> 60ms
         ConcurrentHashMap<BI, Boolean> m =
             new ConcurrentHashMap<BI, Boolean>();
         for (int i = 0; i < size; i++) {
             assertTrue(m.put(new CI(i), true) == null);
         }
         for (int i = 0; i < size; i++) {
             assertTrue(m.containsKey(new CI(i)));
             assertTrue(m.containsKey(new DI(i)));
         }
     }

     /**
      * Elements of classes with erased generic type parameters based
      * on Comparable can be inserted and found.
      */
     public void testGenericComparable() {
         int size = 120;         // makes measured test run time -> 60ms
         ConcurrentHashMap<Object, Boolean> m =
             new ConcurrentHashMap<Object, Boolean>();
         for (int i = 0; i < size; i++) {
             BI bi = new BI(i);
             BS bs = new BS(String.valueOf(i));
             LexicographicList<BI> bis = new LexicographicList<BI>(bi);
             LexicographicList<BS> bss = new LexicographicList<BS>(bs);
             assertTrue(m.putIfAbsent(bis, true) == null);
             assertTrue(m.containsKey(bis));
             if (m.putIfAbsent(bss, true) == null)
                 assertTrue(m.containsKey(bss));
             assertTrue(m.containsKey(bis));
         }
         for (int i = 0; i < size; i++) {
             assertTrue(m.containsKey(Collections.singletonList(new BI(i))));
         }
     }

     /**
      * Elements of non-comparable classes equal to those of classes
      * with erased generic type parameters based on Comparable can be
      * inserted and found.
      */
     public void testGenericComparable2() {
         int size = 500;         // makes measured test run time -> 60ms
         ConcurrentHashMap<Object, Boolean> m =
             new ConcurrentHashMap<Object, Boolean>();
         for (int i = 0; i < size; i++) {
             m.put(Collections.singletonList(new BI(i)), true);
         }

         for (int i = 0; i < size; i++) {
             LexicographicList<BI> bis = new LexicographicList<BI>(new BI(i));
             assertTrue(m.containsKey(bis));
         }
     }

     /**
      * Mixtures of instances of comparable and non-comparable classes
      * can be inserted and found.
      */
     public void testMixedComparable() {
         int size = 1200;        // makes measured test run time -> 35ms
         ConcurrentHashMap<Object, Object> map =
             new ConcurrentHashMap<Object, Object>();
         Random rng = new Random();
         for (int i = 0; i < size; i++) {
             Object x;
             switch (rng.nextInt(4)) {
             case 0:
                 x = new Object();
                 break;
             case 1:
                 x = new CollidingObject(Integer.toString(i));
                 break;
             default:
                 x = new ComparableCollidingObject(Integer.toString(i));
             }
             assertNull(map.put(x, x));
         }
         int count = 0;
         for (Object k : map.keySet()) {
             assertEquals(map.get(k), k);
             ++count;
         }
         assertEquals(count, size);
         assertEquals(map.size(), size);
         for (Object k : map.keySet()) {
             assertEquals(map.put(k, k), k);
         }
     }

     /**
      * clear removes all pairs
      */
     public void testClear() {
         ConcurrentHashMap map = map5();
         map.clear();
         assertEquals(0, map.size());
     }

     /**
      * Maps with same contents are equal
      */
     public void testEquals() {
         ConcurrentHashMap map1 = map5();
         ConcurrentHashMap map2 = map5();
         assertEquals(map1, map2);
         assertEquals(map2, map1);
         map1.clear();
         assertFalse(map1.equals(map2));
         assertFalse(map2.equals(map1));
     }

     /**
      * hashCode() equals sum of each key.hashCode ^ value.hashCode
      */
     public void testHashCode() {
         ConcurrentHashMap<Integer,String> map = map5();
         int sum = 0;
         for (Map.Entry<Integer,String> e : map.entrySet())
             sum += e.getKey().hashCode() ^ e.getValue().hashCode();
         assertEquals(sum, map.hashCode());
     }

     /**
      * contains returns true for contained value
      */
     public void testContains() {
         ConcurrentHashMap map = map5();
         assertTrue(map.contains("A"));
         assertFalse(map.contains("Z"));
     }

     /**
      * containsKey returns true for contained key
      */
     public void testContainsKey() {
         ConcurrentHashMap map = map5();
         assertTrue(map.containsKey(one));
         assertFalse(map.containsKey(zero));
     }

     /**
      * containsValue returns true for held values
      */
     public void testContainsValue() {
         ConcurrentHashMap map = map5();
         assertTrue(map.containsValue("A"));
         assertFalse(map.containsValue("Z"));
     }

     /**
      * enumeration returns an enumeration containing the correct
      * elements
      */
     public void testEnumeration() {
         ConcurrentHashMap map = map5();
         Enumeration e = map.elements();
         int count = 0;
         while (e.hasMoreElements()) {
             count++;
             e.nextElement();
         }
         assertEquals(5, count);
     }

     /**
      * get returns the correct element at the given key,
      * or null if not present
      */
     public void testGet() {
         ConcurrentHashMap map = map5();
         assertEquals("A", (String)map.get(one));
         ConcurrentHashMap empty = new ConcurrentHashMap();
         assertNull(map.get("anything"));
         assertNull(empty.get("anything"));
     }

     /**
      * isEmpty is true of empty map and false for non-empty
      */
     public void testIsEmpty() {
         ConcurrentHashMap empty = new ConcurrentHashMap();
         ConcurrentHashMap map = map5();
         assertTrue(empty.isEmpty());
         assertFalse(map.isEmpty());
     }

     /**
      * keys returns an enumeration containing all the keys from the map
      */
     public void testKeys() {
         ConcurrentHashMap map = map5();
         Enumeration e = map.keys();
         int count = 0;
         while (e.hasMoreElements()) {
             count++;
             e.nextElement();
         }
         assertEquals(5, count);
     }

     /**
      * keySet returns a Set containing all the keys
      */
     public void testKeySet() {
         ConcurrentHashMap map = map5();
         Set s = map.keySet();
         assertEquals(5, s.size());
         assertTrue(s.contains(one));
         assertTrue(s.contains(two));
         assertTrue(s.contains(three));
         assertTrue(s.contains(four));
         assertTrue(s.contains(five));
     }

     /**
      * keySet.toArray returns contains all keys
      */
     public void testKeySetToArray() {
         ConcurrentHashMap map = map5();
         Set s = map.keySet();
         Object[] ar = s.toArray();
         assertTrue(s.containsAll(Arrays.asList(ar)));
         assertEquals(5, ar.length);
         ar[0] = m10;
         assertFalse(s.containsAll(Arrays.asList(ar)));
     }

     /**
      * Values.toArray contains all values
      */
     public void testValuesToArray() {
         ConcurrentHashMap map = map5();
         Collection v = map.values();
         Object[] ar = v.toArray();
         ArrayList s = new ArrayList(Arrays.asList(ar));
         assertEquals(5, ar.length);
         assertTrue(s.contains("A"));
         assertTrue(s.contains("B"));
         assertTrue(s.contains("C"));
         assertTrue(s.contains("D"));
         assertTrue(s.contains("E"));
     }

     /**
      * entrySet.toArray contains all entries
      */
     public void testEntrySetToArray() {
         ConcurrentHashMap map = map5();
         Set s = map.entrySet();
         Object[] ar = s.toArray();
         assertEquals(5, ar.length);
         for (int i = 0; i < 5; ++i) {
             assertTrue(map.containsKey(((Map.Entry)(ar[i])).getKey()));
             assertTrue(map.containsValue(((Map.Entry)(ar[i])).getValue()));
         }
     }

     /**
      * values collection contains all values
      */
     public void testValues() {
         ConcurrentHashMap map = map5();
         Collection s = map.values();
         assertEquals(5, s.size());
         assertTrue(s.contains("A"));
         assertTrue(s.contains("B"));
         assertTrue(s.contains("C"));
         assertTrue(s.contains("D"));
         assertTrue(s.contains("E"));
     }

     /**
      * entrySet contains all pairs
      */
     public void testEntrySet() {
         ConcurrentHashMap map = map5();
         Set s = map.entrySet();
         assertEquals(5, s.size());
         Iterator it = s.iterator();
         while (it.hasNext()) {
             Map.Entry e = (Map.Entry) it.next();
             assertTrue(
                        (e.getKey().equals(one) && e.getValue().equals("A")) ||
                        (e.getKey().equals(two) && e.getValue().equals("B")) ||
                        (e.getKey().equals(three) && e.getValue().equals("C")) ||
                        (e.getKey().equals(four) && e.getValue().equals("D")) ||
                        (e.getKey().equals(five) && e.getValue().equals("E")));
         }
     }

     /**
      * putAll adds all key-value pairs from the given map
      */
     public void testPutAll() {
         ConcurrentHashMap empty = new ConcurrentHashMap();
         ConcurrentHashMap map = map5();
         empty.putAll(map);
         assertEquals(5, empty.size());
         assertTrue(empty.containsKey(one));
         assertTrue(empty.containsKey(two));
         assertTrue(empty.containsKey(three));
         assertTrue(empty.containsKey(four));
         assertTrue(empty.containsKey(five));
     }

     /**
      * putIfAbsent works when the given key is not present
      */
     public void testPutIfAbsent() {
         ConcurrentHashMap map = map5();
         map.putIfAbsent(six, "Z");
         assertTrue(map.containsKey(six));
     }

     /**
      * putIfAbsent does not add the pair if the key is already present
      */
     public void testPutIfAbsent2() {
         ConcurrentHashMap map = map5();
         assertEquals("A", map.putIfAbsent(one, "Z"));
     }

     /**
      * replace fails when the given key is not present
      */
     public void testReplace() {
         ConcurrentHashMap map = map5();
         assertNull(map.replace(six, "Z"));
         assertFalse(map.containsKey(six));
     }

     /**
      * replace succeeds if the key is already present
      */
     public void testReplace2() {
         ConcurrentHashMap map = map5();
         assertNotNull(map.replace(one, "Z"));
         assertEquals("Z", map.get(one));
     }

     /**
      * replace value fails when the given key not mapped to expected value
      */
     public void testReplaceValue() {
         ConcurrentHashMap map = map5();
         assertEquals("A", map.get(one));
         assertFalse(map.replace(one, "Z", "Z"));
         assertEquals("A", map.get(one));
     }

     /**
      * replace value succeeds when the given key mapped to expected value
      */
     public void testReplaceValue2() {
         ConcurrentHashMap map = map5();
         assertEquals("A", map.get(one));
         assertTrue(map.replace(one, "A", "Z"));
         assertEquals("Z", map.get(one));
     }

     /**
      * remove removes the correct key-value pair from the map
      */
     public void testRemove() {
         ConcurrentHashMap map = map5();
         map.remove(five);
         assertEquals(4, map.size());
         assertFalse(map.containsKey(five));
     }

     /**
      * remove(key,value) removes only if pair present
      */
     public void testRemove2() {
         ConcurrentHashMap map = map5();
         map.remove(five, "E");
         assertEquals(4, map.size());
         assertFalse(map.containsKey(five));
         map.remove(four, "A");
         assertEquals(4, map.size());
         assertTrue(map.containsKey(four));
     }

     /**
      * size returns the correct values
      */
     public void testSize() {
         ConcurrentHashMap map = map5();
         ConcurrentHashMap empty = new ConcurrentHashMap();
         assertEquals(0, empty.size());
         assertEquals(5, map.size());
     }

     /**
      * toString contains toString of elements
      */
     public void testToString() {
         ConcurrentHashMap map = map5();
         String s = map.toString();
         for (int i = 1; i <= 5; ++i) {
             assertTrue(s.contains(String.valueOf(i)));
         }
     }

     // Exception tests

     /**
      * Cannot create with only negative capacity
      */
     public void testConstructor1() {
         try {
             new ConcurrentHashMap(-1);
             shouldThrow();
         } catch (IllegalArgumentException success) {}
     }

     /**
      * Constructor (initialCapacity, loadFactor) throws
      * IllegalArgumentException if either argument is negative
      */
     public void testConstructor2() {
         try {
             new ConcurrentHashMap(-1, .75f);
             shouldThrow();
         } catch (IllegalArgumentException success) {}

         try {
             new ConcurrentHashMap(16, -1);
             shouldThrow();
         } catch (IllegalArgumentException success) {}
     }

     /**
      * Constructor (initialCapacity, loadFactor, concurrencyLevel)
      * throws IllegalArgumentException if any argument is negative
      */
     public void testConstructor3() {
         try {
             new ConcurrentHashMap(-1, .75f, 1);
             shouldThrow();
         } catch (IllegalArgumentException success) {}

         try {
             new ConcurrentHashMap(16, -1, 1);
             shouldThrow();
         } catch (IllegalArgumentException success) {}

         try {
             new ConcurrentHashMap(16, .75f, -1);
             shouldThrow();
         } catch (IllegalArgumentException success) {}
     }

     /**
      * ConcurrentHashMap(map) throws NullPointerException if the given
      * map is null
      */
     public void testConstructor4() {
         try {
             new ConcurrentHashMap(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * ConcurrentHashMap(map) creates a new map with the same mappings
      * as the given map
      */
     public void testConstructor5() {
         ConcurrentHashMap map1 = map5();
         ConcurrentHashMap map2 = new ConcurrentHashMap(map5());
         assertTrue(map2.equals(map1));
         map2.put(one, "F");
         assertFalse(map2.equals(map1));
     }

     /**
      * get(null) throws NPE
      */
     public void testGet_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.get(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * containsKey(null) throws NPE
      */
     public void testContainsKey_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.containsKey(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * containsValue(null) throws NPE
      */
     public void testContainsValue_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.containsValue(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * contains(null) throws NPE
      */
     public void testContains_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.contains(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * put(null,x) throws NPE
      */
     public void testPut1_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.put(null, "whatever");
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * put(x, null) throws NPE
      */
     public void testPut2_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.put("whatever", null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * putIfAbsent(null, x) throws NPE
      */
     public void testPutIfAbsent1_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.putIfAbsent(null, "whatever");
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * replace(null, x) throws NPE
      */
     public void testReplace_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.replace(null, "whatever");
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * replace(null, x, y) throws NPE
      */
     public void testReplaceValue_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.replace(null, one, "whatever");
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * putIfAbsent(x, null) throws NPE
      */
     public void testPutIfAbsent2_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.putIfAbsent("whatever", null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * replace(x, null) throws NPE
      */
     public void testReplace2_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.replace("whatever", null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * replace(x, null, y) throws NPE
      */
     public void testReplaceValue2_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.replace("whatever", null, "A");
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * replace(x, y, null) throws NPE
      */
     public void testReplaceValue3_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         try {
             c.replace("whatever", one, null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * remove(null) throws NPE
      */
     public void testRemove1_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         c.put("sadsdf", "asdads");
         try {
             c.remove(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * remove(null, x) throws NPE
      */
     public void testRemove2_NullPointerException() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         c.put("sadsdf", "asdads");
         try {
             c.remove(null, "whatever");
             shouldThrow();
         } catch (NullPointerException success) {}
     }

     /**
      * remove(x, null) returns false
      */
     public void testRemove3() {
         ConcurrentHashMap c = new ConcurrentHashMap(5);
         c.put("sadsdf", "asdads");
         assertFalse(c.remove("sadsdf", null));
     }

     /**
      * A deserialized map equals original
      */
     public void testSerialization() throws Exception {
         Map x = map5();
         Map y = serialClone(x);

         assertNotSame(x, y);
         assertEquals(x.size(), y.size());
         assertEquals(x, y);
         assertEquals(y, x);
     }

     /**
      * SetValue of an EntrySet entry sets value in the map.
      */
     public void testSetValueWriteThrough() {
         // Adapted from a bug report by Eric Zoerner
         ConcurrentHashMap map = new ConcurrentHashMap(2, 5.0f, 1);
         assertTrue(map.isEmpty());
         for (int i = 0; i < 20; i++)
             map.put(new Integer(i), new Integer(i));
         assertFalse(map.isEmpty());
         Map.Entry entry1 = (Map.Entry)map.entrySet().iterator().next();
         // Unless it happens to be first (in which case remainder of
         // test is skipped), remove a possibly-colliding key from map
         // which, under some implementations, may cause entry1 to be
         // cloned in map
         if (!entry1.getKey().equals(new Integer(16))) {
             map.remove(new Integer(16));
             entry1.setValue("XYZ");
             assertTrue(map.containsValue("XYZ")); // fails if write-through broken
         }
     }

 }
	/*
	* Written by Doug Lea with assistance from members of JCP JSR-166
	* Expert Group and released to the public domain, as explained at
	* http://creativecommons.org/publicdomain/zero/1.0/
	* Other contributors include Andrew Wright, Jeffrey Hayes,
	* Pat Fisher, Mike Judd.
	*/

	package jsr166;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.Enumeration;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.Random;
	import java.util.Set;
	import java.util.concurrent.ConcurrentHashMap;

	import junit.framework.Test;
	import junit.framework.TestSuite;

	public class ConcurrentHashMapTest extends JSR166TestCase {
	// android-note: Removed because the CTS runner does a bad job of
	// retrying tests that have suite() declarations.
	//
	// public static void main(String[] args) {
	// main(suite(), args);
	// }
	// public static Test suite() {
	// return new TestSuite(ConcurrentHashMapTest.class);
	// }

	/**
	* Returns a new map from Integers 1-5 to Strings "A"-"E".
	*/
	private static ConcurrentHashMap<Integer, String> map5() {
	ConcurrentHashMap map = new ConcurrentHashMap<Integer, String>(5);
	assertTrue(map.isEmpty());
	map.put(one, "A");
	map.put(two, "B");
	map.put(three, "C");
	map.put(four, "D");
	map.put(five, "E");
	assertFalse(map.isEmpty());
	assertEquals(5, map.size());
	return map;
	}

	/** Re-implement Integer.compare for old java versions */
	static int compare(int x, int y) {
	return (x < y) ? -1 : (x > y) ? 1 : 0;
	}

	// classes for testing Comparable fallbacks
	static class BI implements Comparable<BI> {
	private final int value;
	BI(int value) { this.value = value; }
	public int compareTo(BI other) {
	return compare(value, other.value);
	}
	public boolean equals(Object x) {
	return (x instanceof BI) && ((BI)x).value == value;
	}
	public int hashCode() { return 42; }
	}
	static class CI extends BI { CI(int value) { super(value); } }
	static class DI extends BI { DI(int value) { super(value); } }

	static class BS implements Comparable<BS> {
	private final String value;
	BS(String value) { this.value = value; }
	public int compareTo(BS other) {
	return value.compareTo(other.value);
	}
	public boolean equals(Object x) {
	return (x instanceof BS) && value.equals(((BS)x).value);
	}
	public int hashCode() { return 42; }
	}

	static class LexicographicList<E extends Comparable<E>> extends ArrayList<E>
	implements Comparable<LexicographicList<E>> {
	LexicographicList(Collection<E> c) { super(c); }
	LexicographicList(E e) { super(Collections.singleton(e)); }
	public int compareTo(LexicographicList<E> other) {
	int common = Math.min(size(), other.size());
	int r = 0;
	for (int i = 0; i < common; i++) {
	if ((r = get(i).compareTo(other.get(i))) != 0)
	break;
	}
	if (r == 0)
	r = compare(size(), other.size());
	return r;
	}
	private static final long serialVersionUID = 0;
	}

	static class CollidingObject {
	final String value;
	CollidingObject(final String value) { this.value = value; }
	public int hashCode() { return this.value.hashCode() & 1; }
	public boolean equals(final Object obj) {
	return (obj instanceof CollidingObject) && ((CollidingObject)obj).value.equals(value);
	}
	}

	static class ComparableCollidingObject extends CollidingObject implements Comparable<ComparableCollidingObject> {
	ComparableCollidingObject(final String value) { super(value); }
	public int compareTo(final ComparableCollidingObject o) {
	return value.compareTo(o.value);
	}
	}

	/**
	* Inserted elements that are subclasses of the same Comparable
	* class are found.
	*/
	public void testComparableFamily() {
	int size = 500; // makes measured test run time -> 60ms
	ConcurrentHashMap<BI, Boolean> m =
	new ConcurrentHashMap<BI, Boolean>();
	for (int i = 0; i < size; i++) {
	assertTrue(m.put(new CI(i), true) == null);
	}
	for (int i = 0; i < size; i++) {
	assertTrue(m.containsKey(new CI(i)));
	assertTrue(m.containsKey(new DI(i)));
	}
	}

	/**
	* Elements of classes with erased generic type parameters based
	* on Comparable can be inserted and found.
	*/
	public void testGenericComparable() {
	int size = 120; // makes measured test run time -> 60ms
	ConcurrentHashMap<Object, Boolean> m =
	new ConcurrentHashMap<Object, Boolean>();
	for (int i = 0; i < size; i++) {
	BI bi = new BI(i);
	BS bs = new BS(String.valueOf(i));
	LexicographicList<BI> bis = new LexicographicList<BI>(bi);
	LexicographicList<BS> bss = new LexicographicList<BS>(bs);
	assertTrue(m.putIfAbsent(bis, true) == null);
	assertTrue(m.containsKey(bis));
	if (m.putIfAbsent(bss, true) == null)
	assertTrue(m.containsKey(bss));
	assertTrue(m.containsKey(bis));
	}
	for (int i = 0; i < size; i++) {
	assertTrue(m.containsKey(Collections.singletonList(new BI(i))));
	}
	}

	/**
	* Elements of non-comparable classes equal to those of classes
	* with erased generic type parameters based on Comparable can be
	* inserted and found.
	*/
	public void testGenericComparable2() {
	int size = 500; // makes measured test run time -> 60ms
	ConcurrentHashMap<Object, Boolean> m =
	new ConcurrentHashMap<Object, Boolean>();
	for (int i = 0; i < size; i++) {
	m.put(Collections.singletonList(new BI(i)), true);
	}

	for (int i = 0; i < size; i++) {
	LexicographicList<BI> bis = new LexicographicList<BI>(new BI(i));
	assertTrue(m.containsKey(bis));
	}
	}

	/**
	* Mixtures of instances of comparable and non-comparable classes
	* can be inserted and found.
	*/
	public void testMixedComparable() {
	int size = 1200; // makes measured test run time -> 35ms
	ConcurrentHashMap<Object, Object> map =
	new ConcurrentHashMap<Object, Object>();
	Random rng = new Random();
	for (int i = 0; i < size; i++) {
	Object x;
	switch (rng.nextInt(4)) {
	case 0:
	x = new Object();
	break;
	case 1:
	x = new CollidingObject(Integer.toString(i));
	break;
	default:
	x = new ComparableCollidingObject(Integer.toString(i));
	}
	assertNull(map.put(x, x));
	}
	int count = 0;
	for (Object k : map.keySet()) {
	assertEquals(map.get(k), k);
	++count;
	}
	assertEquals(count, size);
	assertEquals(map.size(), size);
	for (Object k : map.keySet()) {
	assertEquals(map.put(k, k), k);
	}
	}

	/**
	* clear removes all pairs
	*/
	public void testClear() {
	ConcurrentHashMap map = map5();
	map.clear();
	assertEquals(0, map.size());
	}

	/**
	* Maps with same contents are equal
	*/
	public void testEquals() {
	ConcurrentHashMap map1 = map5();
	ConcurrentHashMap map2 = map5();
	assertEquals(map1, map2);
	assertEquals(map2, map1);
	map1.clear();
	assertFalse(map1.equals(map2));
	assertFalse(map2.equals(map1));
	}

	/**
	* hashCode() equals sum of each key.hashCode ^ value.hashCode
	*/
	public void testHashCode() {
	ConcurrentHashMap<Integer,String> map = map5();
	int sum = 0;
	for (Map.Entry<Integer,String> e : map.entrySet())
	sum += e.getKey().hashCode() ^ e.getValue().hashCode();
	assertEquals(sum, map.hashCode());
	}

	/**
	* contains returns true for contained value
	*/
	public void testContains() {
	ConcurrentHashMap map = map5();
	assertTrue(map.contains("A"));
	assertFalse(map.contains("Z"));
	}

	/**
	* containsKey returns true for contained key
	*/
	public void testContainsKey() {
	ConcurrentHashMap map = map5();
	assertTrue(map.containsKey(one));
	assertFalse(map.containsKey(zero));
	}

	/**
	* containsValue returns true for held values
	*/
	public void testContainsValue() {
	ConcurrentHashMap map = map5();
	assertTrue(map.containsValue("A"));
	assertFalse(map.containsValue("Z"));
	}

	/**
	* enumeration returns an enumeration containing the correct
	* elements
	*/
	public void testEnumeration() {
	ConcurrentHashMap map = map5();
	Enumeration e = map.elements();
	int count = 0;
	while (e.hasMoreElements()) {
	count++;
	e.nextElement();
	}
	assertEquals(5, count);
	}

	/**
	* get returns the correct element at the given key,
	* or null if not present
	*/
	public void testGet() {
	ConcurrentHashMap map = map5();
	assertEquals("A", (String)map.get(one));
	ConcurrentHashMap empty = new ConcurrentHashMap();
	assertNull(map.get("anything"));
	assertNull(empty.get("anything"));
	}

	/**
	* isEmpty is true of empty map and false for non-empty
	*/
	public void testIsEmpty() {
	ConcurrentHashMap empty = new ConcurrentHashMap();
	ConcurrentHashMap map = map5();
	assertTrue(empty.isEmpty());
	assertFalse(map.isEmpty());
	}

	/**
	* keys returns an enumeration containing all the keys from the map
	*/
	public void testKeys() {
	ConcurrentHashMap map = map5();
	Enumeration e = map.keys();
	int count = 0;
	while (e.hasMoreElements()) {
	count++;
	e.nextElement();
	}
	assertEquals(5, count);
	}

	/**
	* keySet returns a Set containing all the keys
	*/
	public void testKeySet() {
	ConcurrentHashMap map = map5();
	Set s = map.keySet();
	assertEquals(5, s.size());
	assertTrue(s.contains(one));
	assertTrue(s.contains(two));
	assertTrue(s.contains(three));
	assertTrue(s.contains(four));
	assertTrue(s.contains(five));
	}

	/**
	* keySet.toArray returns contains all keys
	*/
	public void testKeySetToArray() {
	ConcurrentHashMap map = map5();
	Set s = map.keySet();
	Object[] ar = s.toArray();
	assertTrue(s.containsAll(Arrays.asList(ar)));
	assertEquals(5, ar.length);
	ar[0] = m10;
	assertFalse(s.containsAll(Arrays.asList(ar)));
	}

	/**
	* Values.toArray contains all values
	*/
	public void testValuesToArray() {
	ConcurrentHashMap map = map5();
	Collection v = map.values();
	Object[] ar = v.toArray();
	ArrayList s = new ArrayList(Arrays.asList(ar));
	assertEquals(5, ar.length);
	assertTrue(s.contains("A"));
	assertTrue(s.contains("B"));
	assertTrue(s.contains("C"));
	assertTrue(s.contains("D"));
	assertTrue(s.contains("E"));
	}

	/**
	* entrySet.toArray contains all entries
	*/
	public void testEntrySetToArray() {
	ConcurrentHashMap map = map5();
	Set s = map.entrySet();
	Object[] ar = s.toArray();
	assertEquals(5, ar.length);
	for (int i = 0; i < 5; ++i) {
	assertTrue(map.containsKey(((Map.Entry)(ar[i])).getKey()));
	assertTrue(map.containsValue(((Map.Entry)(ar[i])).getValue()));
	}
	}

	/**
	* values collection contains all values
	*/
	public void testValues() {
	ConcurrentHashMap map = map5();
	Collection s = map.values();
	assertEquals(5, s.size());
	assertTrue(s.contains("A"));
	assertTrue(s.contains("B"));
	assertTrue(s.contains("C"));
	assertTrue(s.contains("D"));
	assertTrue(s.contains("E"));
	}

	/**
	* entrySet contains all pairs
	*/
	public void testEntrySet() {
	ConcurrentHashMap map = map5();
	Set s = map.entrySet();
	assertEquals(5, s.size());
	Iterator it = s.iterator();
	while (it.hasNext()) {
	Map.Entry e = (Map.Entry) it.next();
	assertTrue(
	(e.getKey().equals(one) && e.getValue().equals("A")) \|\|
	(e.getKey().equals(two) && e.getValue().equals("B")) \|\|
	(e.getKey().equals(three) && e.getValue().equals("C")) \|\|
	(e.getKey().equals(four) && e.getValue().equals("D")) \|\|
	(e.getKey().equals(five) && e.getValue().equals("E")));
	}
	}

	/**
	* putAll adds all key-value pairs from the given map
	*/
	public void testPutAll() {
	ConcurrentHashMap empty = new ConcurrentHashMap();
	ConcurrentHashMap map = map5();
	empty.putAll(map);
	assertEquals(5, empty.size());
	assertTrue(empty.containsKey(one));
	assertTrue(empty.containsKey(two));
	assertTrue(empty.containsKey(three));
	assertTrue(empty.containsKey(four));
	assertTrue(empty.containsKey(five));
	}

	/**
	* putIfAbsent works when the given key is not present
	*/
	public void testPutIfAbsent() {
	ConcurrentHashMap map = map5();
	map.putIfAbsent(six, "Z");
	assertTrue(map.containsKey(six));
	}

	/**
	* putIfAbsent does not add the pair if the key is already present
	*/
	public void testPutIfAbsent2() {
	ConcurrentHashMap map = map5();
	assertEquals("A", map.putIfAbsent(one, "Z"));
	}

	/**
	* replace fails when the given key is not present
	*/
	public void testReplace() {
	ConcurrentHashMap map = map5();
	assertNull(map.replace(six, "Z"));
	assertFalse(map.containsKey(six));
	}

	/**
	* replace succeeds if the key is already present
	*/
	public void testReplace2() {
	ConcurrentHashMap map = map5();
	assertNotNull(map.replace(one, "Z"));
	assertEquals("Z", map.get(one));
	}

	/**
	* replace value fails when the given key not mapped to expected value
	*/
	public void testReplaceValue() {
	ConcurrentHashMap map = map5();
	assertEquals("A", map.get(one));
	assertFalse(map.replace(one, "Z", "Z"));
	assertEquals("A", map.get(one));
	}

	/**
	* replace value succeeds when the given key mapped to expected value
	*/
	public void testReplaceValue2() {
	ConcurrentHashMap map = map5();
	assertEquals("A", map.get(one));
	assertTrue(map.replace(one, "A", "Z"));
	assertEquals("Z", map.get(one));
	}

	/**
	* remove removes the correct key-value pair from the map
	*/
	public void testRemove() {
	ConcurrentHashMap map = map5();
	map.remove(five);
	assertEquals(4, map.size());
	assertFalse(map.containsKey(five));
	}

	/**
	* remove(key,value) removes only if pair present
	*/
	public void testRemove2() {
	ConcurrentHashMap map = map5();
	map.remove(five, "E");
	assertEquals(4, map.size());
	assertFalse(map.containsKey(five));
	map.remove(four, "A");
	assertEquals(4, map.size());
	assertTrue(map.containsKey(four));
	}

	/**
	* size returns the correct values
	*/
	public void testSize() {
	ConcurrentHashMap map = map5();
	ConcurrentHashMap empty = new ConcurrentHashMap();
	assertEquals(0, empty.size());
	assertEquals(5, map.size());
	}

	/**
	* toString contains toString of elements
	*/
	public void testToString() {
	ConcurrentHashMap map = map5();
	String s = map.toString();
	for (int i = 1; i <= 5; ++i) {
	assertTrue(s.contains(String.valueOf(i)));
	}
	}

	// Exception tests

	/**
	* Cannot create with only negative capacity
	*/
	public void testConstructor1() {
	try {
	new ConcurrentHashMap(-1);
	shouldThrow();
	} catch (IllegalArgumentException success) {}
	}

	/**
	* Constructor (initialCapacity, loadFactor) throws
	* IllegalArgumentException if either argument is negative
	*/
	public void testConstructor2() {
	try {
	new ConcurrentHashMap(-1, .75f);
	shouldThrow();
	} catch (IllegalArgumentException success) {}

	try {
	new ConcurrentHashMap(16, -1);
	shouldThrow();
	} catch (IllegalArgumentException success) {}
	}

	/**
	* Constructor (initialCapacity, loadFactor, concurrencyLevel)
	* throws IllegalArgumentException if any argument is negative
	*/
	public void testConstructor3() {
	try {
	new ConcurrentHashMap(-1, .75f, 1);
	shouldThrow();
	} catch (IllegalArgumentException success) {}

	try {
	new ConcurrentHashMap(16, -1, 1);
	shouldThrow();
	} catch (IllegalArgumentException success) {}

	try {
	new ConcurrentHashMap(16, .75f, -1);
	shouldThrow();
	} catch (IllegalArgumentException success) {}
	}

	/**
	* ConcurrentHashMap(map) throws NullPointerException if the given
	* map is null
	*/
	public void testConstructor4() {
	try {
	new ConcurrentHashMap(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* ConcurrentHashMap(map) creates a new map with the same mappings
	* as the given map
	*/
	public void testConstructor5() {
	ConcurrentHashMap map1 = map5();
	ConcurrentHashMap map2 = new ConcurrentHashMap(map5());
	assertTrue(map2.equals(map1));
	map2.put(one, "F");
	assertFalse(map2.equals(map1));
	}

	/**
	* get(null) throws NPE
	*/
	public void testGet_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.get(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* containsKey(null) throws NPE
	*/
	public void testContainsKey_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.containsKey(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* containsValue(null) throws NPE
	*/
	public void testContainsValue_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.containsValue(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* contains(null) throws NPE
	*/
	public void testContains_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.contains(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* put(null,x) throws NPE
	*/
	public void testPut1_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.put(null, "whatever");
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* put(x, null) throws NPE
	*/
	public void testPut2_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.put("whatever", null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* putIfAbsent(null, x) throws NPE
	*/
	public void testPutIfAbsent1_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.putIfAbsent(null, "whatever");
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* replace(null, x) throws NPE
	*/
	public void testReplace_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.replace(null, "whatever");
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* replace(null, x, y) throws NPE
	*/
	public void testReplaceValue_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.replace(null, one, "whatever");
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* putIfAbsent(x, null) throws NPE
	*/
	public void testPutIfAbsent2_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.putIfAbsent("whatever", null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* replace(x, null) throws NPE
	*/
	public void testReplace2_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.replace("whatever", null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* replace(x, null, y) throws NPE
	*/
	public void testReplaceValue2_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.replace("whatever", null, "A");
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* replace(x, y, null) throws NPE
	*/
	public void testReplaceValue3_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	try {
	c.replace("whatever", one, null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* remove(null) throws NPE
	*/
	public void testRemove1_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	c.put("sadsdf", "asdads");
	try {
	c.remove(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* remove(null, x) throws NPE
	*/
	public void testRemove2_NullPointerException() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	c.put("sadsdf", "asdads");
	try {
	c.remove(null, "whatever");
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	/**
	* remove(x, null) returns false
	*/
	public void testRemove3() {
	ConcurrentHashMap c = new ConcurrentHashMap(5);
	c.put("sadsdf", "asdads");
	assertFalse(c.remove("sadsdf", null));
	}

	/**
	* A deserialized map equals original
	*/
	public void testSerialization() throws Exception {
	Map x = map5();
	Map y = serialClone(x);

	assertNotSame(x, y);
	assertEquals(x.size(), y.size());
	assertEquals(x, y);
	assertEquals(y, x);
	}

	/**
	* SetValue of an EntrySet entry sets value in the map.
	*/
	public void testSetValueWriteThrough() {
	// Adapted from a bug report by Eric Zoerner
	ConcurrentHashMap map = new ConcurrentHashMap(2, 5.0f, 1);
	assertTrue(map.isEmpty());
	for (int i = 0; i < 20; i++)
	map.put(new Integer(i), new Integer(i));
	assertFalse(map.isEmpty());
	Map.Entry entry1 = (Map.Entry)map.entrySet().iterator().next();
	// Unless it happens to be first (in which case remainder of
	// test is skipped), remove a possibly-colliding key from map
	// which, under some implementations, may cause entry1 to be
	// cloned in map
	if (!entry1.getKey().equals(new Integer(16))) {
	map.remove(new Integer(16));
	entry1.setValue("XYZ");
	assertTrue(map.containsValue("XYZ")); // fails if write-through broken
	}
	}

	}