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Commons Collections example source code file (AbstractTestCollection.java)

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

Java - Commons Collections tags/keywords

arraylist, collection, collection, concurrentmodification, concurrentmodificationexception, empty, full, full, hashset, io, iterator, iterator, object, object, reflection, unsupportedoperationexception, util

The Commons Collections AbstractTestCollection.java source code

/*
 *  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.commons.collections.collection;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.ConcurrentModificationException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;

import org.apache.commons.collections.AbstractTestObject;

/**
 * Abstract test class for {@link java.util.Collection} methods and contracts.
 * <p>
 * You should create a concrete subclass of this class to test any custom
 * {@link Collection} implementation.  At minimum, you'll have to 
 * implement the {@link #makeCollection()} method.  You might want to 
 * override some of the additional public methods as well:
 * <p>
 * <b>Element Population Methods
 * <p>
 * Override these if your collection restricts what kind of elements are
 * allowed (for instance, if <code>null is not permitted):
 * <ul>
 * <li>{@link #getFullElements()}
 * <li>{@link #getOtherElements()}
 * </ul>
 * <p>
 * <b>Supported Operation Methods
 * <p>
 * Override these if your collection doesn't support certain operations:
 * <ul>
 * <li>{@link #isAddSupported()}
 * <li>{@link #isRemoveSupported()}
 * <li>{@link #areEqualElementsDistinguishable()}
 * <li>{@link #isNullSupported()}
 * <li>{@link #isFailFastSupported()}
 * </ul>
 * <p>
 * <b>Fixture Methods
 * <p>
 * Fixtures are used to verify that the the operation results in correct state
 * for the collection.  Basically, the operation is performed against your
 * collection implementation, and an identical operation is performed against a
 * <i>confirmed collection implementation.  A confirmed collection
 * implementation is something like <code>java.util.ArrayList, which is
 * known to conform exactly to its collection interface's contract.  After the
 * operation takes place on both your collection implementation and the
 * confirmed collection implementation, the two collections are compared to see
 * if their state is identical.  The comparison is usually much more involved
 * than a simple <code>equals test.  This verification is used to ensure
 * proper modifications are made along with ensuring that the collection does
 * not change when read-only modifications are made.
 * <p>
 * The {@link #collection} field holds an instance of your collection
 * implementation; the {@link #confirmed} field holds an instance of the
 * confirmed collection implementation.  The {@link #resetEmpty()} and 
 * {@link #resetFull()} methods set these fields to empty or full collections,
 * so that tests can proceed from a known state.
 * <p>
 * After a modification operation to both {@link #collection} and
 * {@link #confirmed}, the {@link #verify()} method is invoked to compare
 * the results.  You may want to override {@link #verify()} to perform
 * additional verifications.  For instance, when testing the collection
 * views of a map, {@link AbstractTestMap} would override {@link #verify()} to make
 * sure the map is changed after the collection view is changed.
 * <p>
 * If you're extending this class directly, you will have to provide 
 * implementations for the following:
 * <ul>
 * <li>{@link #makeConfirmedCollection()}
 * <li>{@link #makeConfirmedFullCollection()}
 * </ul>
 * <p>
 * Those methods should provide a confirmed collection implementation 
 * that's compatible with your collection implementation.
 * <p>
 * If you're extending {@link AbstractTestList}, {@link AbstractTestSet},
 * or {@link AbstractTestBag}, you probably don't have to worry about the
 * above methods, because those three classes already override the methods
 * to provide standard JDK confirmed collections.<P>
 * <p>
 * <b>Other notes
 * <p>
 * If your {@link Collection} fails one of these tests by design,
 * you may still use this base set of cases.  Simply override the
 * test case (method) your {@link Collection} fails.
 *
 * @version $Revision: 646780 $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Rodney Waldhoff
 * @author Paul Jack
 * @author Michael A. Smith
 * @author Neil O'Toole
 * @author Stephen Colebourne
 */
public abstract class AbstractTestCollection extends AbstractTestObject {

    //
    // NOTE: 
    //
    // Collection doesn't define any semantics for equals, and recommends you
    // use reference-based default behavior of Object.equals.  (And a test for
    // that already exists in AbstractTestObject).  Tests for equality of lists, sets
    // and bags will have to be written in test subclasses.  Thus, there is no
    // tests on Collection.equals nor any for Collection.hashCode.
    //


    // These fields are used by reset() and verify(), and any test
    // method that tests a modification.

    /** 
     *  A collection instance that will be used for testing.
     */
    public Collection collection;

    /** 
     *  Confirmed collection.  This is an instance of a collection that is
     *  confirmed to conform exactly to the java.util.Collection contract.
     *  Modification operations are tested by performing a mod on your 
     *  collection, performing the exact same mod on an equivalent confirmed
     *  collection, and then calling verify() to make sure your collection
     *  still matches the confirmed collection.
     */
    public Collection confirmed;

    /**
     * JUnit constructor.
     * 
     * @param testName  the test class name
     */
    public AbstractTestCollection(String testName) {
        super(testName);
    }

    //-----------------------------------------------------------------------
    /**
     *  Specifies whether equal elements in the collection are, in fact,
     *  distinguishable with information not readily available.  That is, if a
     *  particular value is to be removed from the collection, then there is
     *  one and only one value that can be removed, even if there are other
     *  elements which are equal to it.  
     *
     *  <P>In most collection cases, elements are not distinguishable (equal is
     *  equal), thus this method defaults to return false.  In some cases,
     *  however, they are.  For example, the collection returned from the map's
     *  values() collection view are backed by the map, so while there may be
     *  two values that are equal, their associated keys are not.  Since the
     *  keys are distinguishable, the values are.
     *
     *  <P>This flag is used to skip some verifications for iterator.remove()
     *  where it is impossible to perform an equivalent modification on the
     *  confirmed collection because it is not possible to determine which
     *  value in the confirmed collection to actually remove.  Tests that
     *  override the default (i.e. where equal elements are distinguishable),
     *  should provide additional tests on iterator.remove() to make sure the
     *  proper elements are removed when remove() is called on the iterator.
     **/
    public boolean areEqualElementsDistinguishable() {
        return false;
    }

    /**
     *  Returns true if the collections produced by 
     *  {@link #makeCollection()} and {@link #makeFullCollection()}
     *  support the <code>add and addAll
     *  operations.<P>
     *  Default implementation returns true.  Override if your collection
     *  class does not support add or addAll.
     */
    public boolean isAddSupported() {
        return true;
    }

    /**
     *  Returns true if the collections produced by 
     *  {@link #makeCollection()} and {@link #makeFullCollection()}
     *  support the <code>remove, removeAll,
     *  <code>retainAll, clear and
     *  <code>iterator().remove() methods.
     *  Default implementation returns true.  Override if your collection
     *  class does not support removal operations.
     */
    public boolean isRemoveSupported() {
        return true;
    }

    /**
     * Returns true to indicate that the collection supports holding null.
     * The default implementation returns true;
     */
    public boolean isNullSupported() {
        return true;
    }

    /**
     * Returns true to indicate that the collection supports fail fast iterators.
     * The default implementation returns true;
     */
    public boolean isFailFastSupported() {
        return false;
    }

    /**
     * Returns true to indicate that the collection supports equals() comparisons.
     * This implementation returns false;
     */
    public boolean isEqualsCheckable() {
        return false;
    }

    //-----------------------------------------------------------------------
    /**
     *  Verifies that {@link #collection} and {@link #confirmed} have 
     *  identical state.
     */
    public void verify() {
        int confirmedSize = confirmed.size();
        assertEquals("Collection size should match confirmed collection's",
                     confirmedSize, collection.size());
        assertEquals("Collection isEmpty() result should match confirmed " +
                     " collection's", 
                     confirmed.isEmpty(), collection.isEmpty());

        // verify the collections are the same by attempting to match each
        // object in the collection and confirmed collection.  To account for
        // duplicates and differing orders, each confirmed element is copied
        // into an array and a flag is maintained for each element to determine
        // whether it has been matched once and only once.  If all elements in
        // the confirmed collection are matched once and only once and there
        // aren't any elements left to be matched in the collection,
        // verification is a success.

        // copy each collection value into an array
        Object[] confirmedValues = new Object[confirmedSize];

        Iterator iter;

        iter = confirmed.iterator(); 
        int pos = 0;
        while(iter.hasNext()) {
            confirmedValues[pos++] = iter.next();
        }

        // allocate an array of boolean flags for tracking values that have
        // been matched once and only once.
        boolean[] matched = new boolean[confirmedSize];
        
        // now iterate through the values of the collection and try to match
        // the value with one in the confirmed array.
        iter = collection.iterator();
        while(iter.hasNext()) {
            Object o = iter.next();
            boolean match = false;
            for(int i = 0; i < confirmedSize; i++) {
                if(matched[i]) {
                    // skip values already matched
                    continue;
                }
                if(o == confirmedValues[i] ||
                   (o != null && o.equals(confirmedValues[i]))) {
                    // values matched
                    matched[i] = true;
                    match = true;
                    break;
                }
            }
            // no match found!
            if(!match) {
                fail("Collection should not contain a value that the " +
                     "confirmed collection does not have: " + o +
                     "\nTest: " + collection + "\nReal: " + confirmed);
            }
        }
        
        // make sure there aren't any unmatched values
        for(int i = 0; i < confirmedSize; i++) {
            if(!matched[i]) {
                // the collection didn't match all the confirmed values
                fail("Collection should contain all values that are in the confirmed collection" +
                     "\nTest: " + collection + "\nReal: " + confirmed);
            }
        }
    }
    
    //-----------------------------------------------------------------------
    /**
     *  Resets the {@link #collection} and {@link #confirmed} fields to empty
     *  collections.  Invoke this method before performing a modification
     *  test.
     */
    public void resetEmpty() {
        this.collection = makeCollection();
        this.confirmed = makeConfirmedCollection();
    }

    /**
     *  Resets the {@link #collection} and {@link #confirmed} fields to full
     *  collections.  Invoke this method before performing a modification
     *  test.
     */
    public void resetFull() {
        this.collection = makeFullCollection();
        this.confirmed = makeConfirmedFullCollection();
    }

    //-----------------------------------------------------------------------
    /**
     *  Returns a confirmed empty collection.
     *  For instance, an {@link java.util.ArrayList} for lists or a
     *  {@link java.util.HashSet} for sets.
     *
     *  @return a confirmed empty collection
     */
    public abstract Collection makeConfirmedCollection();

    /**
     *  Returns a confirmed full collection.
     *  For instance, an {@link java.util.ArrayList} for lists or a
     *  {@link java.util.HashSet} for sets.  The returned collection
     *  should contain the elements returned by {@link #getFullElements()}.
     *
     *  @return a confirmed full collection
     */
    public abstract Collection makeConfirmedFullCollection();

    /**
     * Return a new, empty {@link Collection} to be used for testing.
     */
    public abstract Collection makeCollection();

    /**
     *  Returns a full collection to be used for testing.  The collection
     *  returned by this method should contain every element returned by
     *  {@link #getFullElements()}.  The default implementation, in fact,
     *  simply invokes <code>addAll on an empty collection with
     *  the results of {@link #getFullElements()}.  Override this default
     *  if your collection doesn't support addAll.
     */
    public Collection makeFullCollection() {
        Collection c = makeCollection();
        c.addAll(Arrays.asList(getFullElements()));
        return c;
    }

    /**
     *  Returns an empty collection for Object tests.
     */
    public Object makeObject() {
        return makeCollection();
    }

    /**
     * Creates a new Map Entry that is independent of the first and the map.
     */
    public Map.Entry cloneMapEntry(Map.Entry entry) {
        HashMap map = new HashMap();
        map.put(entry.getKey(), entry.getValue());
        return (Map.Entry) map.entrySet().iterator().next();
    }

    //-----------------------------------------------------------------------
    /**
     *  Returns an array of objects that are contained in a collection
     *  produced by {@link #makeFullCollection()}.  Every element in the
     *  returned array <I>must be an element in a full collection.

* The default implementation returns a heterogenous array of * objects with some duplicates. null is added if allowed. * Override if you require specific testing elements. Note that if you * override {@link #makeFullCollection()}, you <I>must override * this method to reflect the contents of a full collection. */ public Object[] getFullElements() { if (isNullSupported()) { ArrayList list = new ArrayList(); list.addAll(Arrays.asList(getFullNonNullElements())); list.add(4, null); return list.toArray(); } else { return (Object[]) getFullNonNullElements().clone(); } } /** * Returns an array of elements that are <I>not contained in a * full collection. Every element in the returned array must * not exist in a collection returned by {@link #makeFullCollection()}. * The default implementation returns a heterogenous array of elements * without null. Note that some of the tests add these elements * to an empty or full collection, so if your collection restricts * certain kinds of elements, you should override this method. */ public Object[] getOtherElements() { return getOtherNonNullElements(); } //----------------------------------------------------------------------- /** * Returns a list of elements suitable for return by * {@link #getFullElements()}. The array returned by this method * does not include null, but does include a variety of objects * of different types. Override getFullElements to return * the results of this method if your collection does not support * the null element. */ public Object[] getFullNonNullElements() { return new Object[] { new String(""), new String("One"), new Integer(2), "Three", new Integer(4), "One", new Double(5), new Float(6), "Seven", "Eight", new String("Nine"), new Integer(10), new Short((short)11), new Long(12), "Thirteen", "14", "15", new Byte((byte)16) }; } /** * Returns the default list of objects returned by * {@link #getOtherElements()}. Includes many objects * of different types. */ public Object[] getOtherNonNullElements() { return new Object[] { new Integer(0), new Float(0), new Double(0), "Zero", new Short((short)0), new Byte((byte)0), new Long(0), new Character('\u0000'), "0" }; } /** * Returns a list of string elements suitable for return by * {@link #getFullElements()}. Override getFullElements to return * the results of this method if your collection does not support * heterogenous elements or the null element. */ public Object[] getFullNonNullStringElements() { return new Object[] { "If","the","dull","substance","of","my","flesh","were","thought", "Injurious","distance","could","not","stop","my","way", }; } /** * Returns a list of string elements suitable for return by * {@link #getOtherElements()}. Override getOtherElements to return * the results of this method if your collection does not support * heterogenous elements or the null element. */ public Object[] getOtherNonNullStringElements() { return new Object[] { "For","then","despite",/* of */"space","I","would","be","brought", "From","limits","far","remote","where","thou","dost","stay" }; } // Tests //----------------------------------------------------------------------- /** * Tests {@link Collection#add(Object)}. */ public void testCollectionAdd() { if (!isAddSupported()) return; Object[] elements = getFullElements(); for (int i = 0; i < elements.length; i++) { resetEmpty(); boolean r = collection.add(elements[i]); confirmed.add(elements[i]); verify(); assertTrue("Empty collection changed after add", r); assertEquals("Collection size is 1 after first add", 1, collection.size()); } resetEmpty(); int size = 0; for (int i = 0; i < elements.length; i++) { boolean r = collection.add(elements[i]); confirmed.add(elements[i]); verify(); if (r) size++; assertEquals("Collection size should grow after add", size, collection.size()); assertTrue("Collection should contain added element", collection.contains(elements[i])); } } /** * Tests {@link Collection#addAll(Collection)}. */ public void testCollectionAddAll() { if (!isAddSupported()) return; resetEmpty(); Object[] elements = getFullElements(); boolean r = collection.addAll(Arrays.asList(elements)); confirmed.addAll(Arrays.asList(elements)); verify(); assertTrue("Empty collection should change after addAll", r); for (int i = 0; i < elements.length; i++) { assertTrue("Collection should contain added element", collection.contains(elements[i])); } resetFull(); int size = collection.size(); elements = getOtherElements(); r = collection.addAll(Arrays.asList(elements)); confirmed.addAll(Arrays.asList(elements)); verify(); assertTrue("Full collection should change after addAll", r); for (int i = 0; i < elements.length; i++) { assertTrue("Full collection should contain added element", collection.contains(elements[i])); } assertEquals("Size should increase after addAll", size + elements.length, collection.size()); resetFull(); size = collection.size(); r = collection.addAll(Arrays.asList(getFullElements())); confirmed.addAll(Arrays.asList(getFullElements())); verify(); if (r) { assertTrue("Size should increase if addAll returns true", size < collection.size()); } else { assertEquals("Size should not change if addAll returns false", size, collection.size()); } } /** * If {@link #isAddSupported()} returns false, tests that add operations * raise <code>UnsupportedOperationException. */ public void testUnsupportedAdd() { if (isAddSupported()) return; resetEmpty(); try { collection.add(new Object()); fail("Emtpy collection should not support add."); } catch (UnsupportedOperationException e) { // expected } // make sure things didn't change even if the expected exception was // thrown. verify(); try { collection.addAll(Arrays.asList(getFullElements())); fail("Emtpy collection should not support addAll."); } catch (UnsupportedOperationException e) { // expected } // make sure things didn't change even if the expected exception was // thrown. verify(); resetFull(); try { collection.add(new Object()); fail("Full collection should not support add."); } catch (UnsupportedOperationException e) { // expected } // make sure things didn't change even if the expected exception was // thrown. verify(); try { collection.addAll(Arrays.asList(getOtherElements())); fail("Full collection should not support addAll."); } catch (UnsupportedOperationException e) { // expected } // make sure things didn't change even if the expected exception was // thrown. verify(); } /** * Test {@link Collection#clear()}. */ public void testCollectionClear() { if (!isRemoveSupported()) return; resetEmpty(); collection.clear(); // just to make sure it doesn't raise anything verify(); resetFull(); collection.clear(); confirmed.clear(); verify(); } /** * Tests {@link Collection#contains(Object)}. */ public void testCollectionContains() { Object[] elements; resetEmpty(); elements = getFullElements(); for(int i = 0; i < elements.length; i++) { assertTrue("Empty collection shouldn't contain element[" + i + "]", !collection.contains(elements[i])); } // make sure calls to "contains" don't change anything verify(); elements = getOtherElements(); for(int i = 0; i < elements.length; i++) { assertTrue("Empty collection shouldn't contain element[" + i + "]", !collection.contains(elements[i])); } // make sure calls to "contains" don't change anything verify(); resetFull(); elements = getFullElements(); for(int i = 0; i < elements.length; i++) { assertTrue("Full collection should contain element[" + i + "]", collection.contains(elements[i])); } // make sure calls to "contains" don't change anything verify(); resetFull(); elements = getOtherElements(); for(int i = 0; i < elements.length; i++) { assertTrue("Full collection shouldn't contain element", !collection.contains(elements[i])); } } /** * Tests {@link Collection#containsAll(Collection)}. */ public void testCollectionContainsAll() { resetEmpty(); Collection col = new HashSet(); assertTrue("Every Collection should contain all elements of an " + "empty Collection.", collection.containsAll(col)); col.addAll(Arrays.asList(getOtherElements())); assertTrue("Empty Collection shouldn't contain all elements of " + "a non-empty Collection.", !collection.containsAll(col)); // make sure calls to "containsAll" don't change anything verify(); resetFull(); assertTrue("Full collection shouldn't contain other elements", !collection.containsAll(col)); col.clear(); col.addAll(Arrays.asList(getFullElements())); assertTrue("Full collection should containAll full elements", collection.containsAll(col)); // make sure calls to "containsAll" don't change anything verify(); int min = (getFullElements().length < 2 ? 0 : 2); int max = (getFullElements().length == 1 ? 1 : (getFullElements().length <= 5 ? getFullElements().length - 1 : 5)); col = Arrays.asList(getFullElements()).subList(min, max); assertTrue("Full collection should containAll partial full " + "elements", collection.containsAll(col)); assertTrue("Full collection should containAll itself", collection.containsAll(collection)); // make sure calls to "containsAll" don't change anything verify(); col = new ArrayList(); col.addAll(Arrays.asList(getFullElements())); col.addAll(Arrays.asList(getFullElements())); assertTrue("Full collection should containAll duplicate full " + "elements", collection.containsAll(col)); // make sure calls to "containsAll" don't change anything verify(); } /** * Tests {@link Collection#isEmpty()}. */ public void testCollectionIsEmpty() { resetEmpty(); assertEquals("New Collection should be empty.", true, collection.isEmpty()); // make sure calls to "isEmpty() don't change anything verify(); resetFull(); assertEquals("Full collection shouldn't be empty", false, collection.isEmpty()); // make sure calls to "isEmpty() don't change anything verify(); } /** * Tests the read-only functionality of {@link Collection#iterator()}. */ public void testCollectionIterator() { resetEmpty(); Iterator it1 = collection.iterator(); assertEquals("Iterator for empty Collection shouldn't have next.", false, it1.hasNext()); try { it1.next(); fail("Iterator at end of Collection should throw " + "NoSuchElementException when next is called."); } catch(NoSuchElementException e) { // expected } // make sure nothing has changed after non-modification verify(); resetFull(); it1 = collection.iterator(); for (int i = 0; i < collection.size(); i++) { assertTrue("Iterator for full collection should haveNext", it1.hasNext()); it1.next(); } assertTrue("Iterator should be finished", !it1.hasNext()); ArrayList list = new ArrayList(); it1 = collection.iterator(); for (int i = 0; i < collection.size(); i++) { Object next = it1.next(); assertTrue("Collection should contain element returned by " + "its iterator", collection.contains(next)); list.add(next); } try { it1.next(); fail("iterator.next() should raise NoSuchElementException " + "after it finishes"); } catch (NoSuchElementException e) { // expected } // make sure nothing has changed after non-modification verify(); } /** * Tests removals from {@link Collection#iterator()}. */ public void testCollectionIteratorRemove() { if (!isRemoveSupported()) return; resetEmpty(); try { collection.iterator().remove(); fail("New iterator.remove should raise IllegalState"); } catch (IllegalStateException e) { // expected } verify(); try { Iterator iter = collection.iterator(); iter.hasNext(); iter.remove(); fail("New iterator.remove should raise IllegalState " + "even after hasNext"); } catch (IllegalStateException e) { // expected } verify(); resetFull(); int size = collection.size(); Iterator iter = collection.iterator(); while (iter.hasNext()) { Object o = iter.next(); // TreeMap reuses the Map Entry, so the verify below fails // Clone it here if necessary if (o instanceof Map.Entry) { o = cloneMapEntry((Map.Entry) o); } iter.remove(); // if the elements aren't distinguishable, we can just remove a // matching element from the confirmed collection and verify // contents are still the same. Otherwise, we don't have the // ability to distinguish the elements and determine which to // remove from the confirmed collection (in which case, we don't // verify because we don't know how). // // see areEqualElementsDistinguishable() if(!areEqualElementsDistinguishable()) { confirmed.remove(o); verify(); } size--; assertEquals("Collection should shrink by one after " + "iterator.remove", size, collection.size()); } assertTrue("Collection should be empty after iterator purge", collection.isEmpty()); resetFull(); iter = collection.iterator(); iter.next(); iter.remove(); try { iter.remove(); fail("Second iter.remove should raise IllegalState"); } catch (IllegalStateException e) { // expected } } /** * Tests {@link Collection#remove(Object)}. */ public void testCollectionRemove() { if (!isRemoveSupported()) return; resetEmpty(); Object[] elements = getFullElements(); for (int i = 0; i < elements.length; i++) { assertTrue("Shouldn't remove nonexistent element", !collection.remove(elements[i])); verify(); } Object[] other = getOtherElements(); resetFull(); for (int i = 0; i < other.length; i++) { assertTrue("Shouldn't remove nonexistent other element", !collection.remove(other[i])); verify(); } int size = collection.size(); for (int i = 0; i < elements.length; i++) { resetFull(); assertTrue("Collection should remove extant element: " + elements[i], collection.remove(elements[i])); // if the elements aren't distinguishable, we can just remove a // matching element from the confirmed collection and verify // contents are still the same. Otherwise, we don't have the // ability to distinguish the elements and determine which to // remove from the confirmed collection (in which case, we don't // verify because we don't know how). // // see areEqualElementsDistinguishable() if(!areEqualElementsDistinguishable()) { confirmed.remove(elements[i]); verify(); } assertEquals("Collection should shrink after remove", size - 1, collection.size()); } } /** * Tests {@link Collection#removeAll(Collection)}. */ public void testCollectionRemoveAll() { if (!isRemoveSupported()) return; resetEmpty(); assertTrue("Emtpy collection removeAll should return false for " + "empty input", !collection.removeAll(Collections.EMPTY_SET)); verify(); assertTrue("Emtpy collection removeAll should return false for " + "nonempty input", !collection.removeAll(new ArrayList(collection))); verify(); resetFull(); assertTrue("Full collection removeAll should return false for " + "empty input", !collection.removeAll(Collections.EMPTY_SET)); verify(); assertTrue("Full collection removeAll should return false for other elements", !collection.removeAll(Arrays.asList(getOtherElements()))); verify(); assertTrue("Full collection removeAll should return true for full elements", collection.removeAll(new HashSet(collection))); confirmed.removeAll(new HashSet(confirmed)); verify(); resetFull(); int size = collection.size(); int min = (getFullElements().length < 2 ? 0 : 2); int max = (getFullElements().length == 1 ? 1 : (getFullElements().length <= 5 ? getFullElements().length - 1 : 5)); Collection all = Arrays.asList(getFullElements()).subList(min, max); assertTrue("Full collection removeAll should work", collection.removeAll(all)); confirmed.removeAll(all); verify(); assertTrue("Collection should shrink after removeAll", collection.size() < size); Iterator iter = all.iterator(); while (iter.hasNext()) { assertTrue("Collection shouldn't contain removed element", !collection.contains(iter.next())); } } /** * Tests {@link Collection#retainAll(Collection)}. */ public void testCollectionRetainAll() { if (!isRemoveSupported()) return; resetEmpty(); List elements = Arrays.asList(getFullElements()); List other = Arrays.asList(getOtherElements()); assertTrue("Empty retainAll() should return false", !collection.retainAll(Collections.EMPTY_SET)); verify(); assertTrue("Empty retainAll() should return false", !collection.retainAll(elements)); verify(); resetFull(); assertTrue("Collection should change from retainAll empty", collection.retainAll(Collections.EMPTY_SET)); confirmed.retainAll(Collections.EMPTY_SET); verify(); resetFull(); assertTrue("Collection changed from retainAll other", collection.retainAll(other)); confirmed.retainAll(other); verify(); resetFull(); int size = collection.size(); assertTrue("Collection shouldn't change from retainAll elements", !collection.retainAll(elements)); verify(); assertEquals("Collection size shouldn't change", size, collection.size()); if (getFullElements().length > 1) { resetFull(); size = collection.size(); int min = (getFullElements().length < 2 ? 0 : 2); int max = (getFullElements().length <= 5 ? getFullElements().length - 1 : 5); assertTrue("Collection should changed by partial retainAll", collection.retainAll(elements.subList(min, max))); confirmed.retainAll(elements.subList(min, max)); verify(); Iterator iter = collection.iterator(); while (iter.hasNext()) { assertTrue("Collection only contains retained element", elements.subList(min, max).contains(iter.next())); } } resetFull(); HashSet set = new HashSet(elements); size = collection.size(); assertTrue("Collection shouldn't change from retainAll without " + "duplicate elements", !collection.retainAll(set)); verify(); assertEquals("Collection size didn't change from nonduplicate " + "retainAll", size, collection.size()); } /** * Tests {@link Collection#size()}. */ public void testCollectionSize() { resetEmpty(); assertEquals("Size of new Collection is 0.", 0, collection.size()); resetFull(); assertTrue("Size of full collection should be greater than zero", collection.size() > 0); } /** * Tests {@link Collection#toArray()}. */ public void testCollectionToArray() { resetEmpty(); assertEquals("Empty Collection should return empty array for toArray", 0, collection.toArray().length); resetFull(); Object[] array = collection.toArray(); assertEquals("Full collection toArray should be same size as " + "collection", array.length, collection.size()); Object[] confirmedArray = confirmed.toArray(); assertEquals("length of array from confirmed collection should " + "match the length of the collection's array", confirmedArray.length, array.length); boolean[] matched = new boolean[array.length]; for (int i = 0; i < array.length; i++) { assertTrue("Collection should contain element in toArray", collection.contains(array[i])); boolean match = false; // find a match in the confirmed array for(int j = 0; j < array.length; j++) { // skip already matched if(matched[j]) continue; if(array[i] == confirmedArray[j] || (array[i] != null && array[i].equals(confirmedArray[j]))) { matched[j] = true; match = true; break; } } if(!match) { fail("element " + i + " in returned array should be found " + "in the confirmed collection's array"); } } for(int i = 0; i < matched.length; i++) { assertEquals("Collection should return all its elements in " + "toArray", true, matched[i]); } } /** * Tests {@link Collection#toArray(Object[])}. */ public void testCollectionToArray2() { resetEmpty(); Object[] a = new Object[] { new Object(), null, null }; Object[] array = collection.toArray(a); assertEquals("Given array shouldn't shrink", array, a); assertEquals("Last element should be set to null", a[0], null); verify(); resetFull(); try { array = collection.toArray(new Void[0]); fail("toArray(new Void[0]) should raise ArrayStore"); } catch (ArrayStoreException e) { // expected } verify(); try { array = collection.toArray(null); fail("toArray(null) should raise NPE"); } catch (NullPointerException e) { // expected } verify(); array = collection.toArray(new Object[0]); a = collection.toArray(); assertEquals("toArrays should be equal", Arrays.asList(array), Arrays.asList(a)); // Figure out if they're all the same class // TODO: It'd be nicer to detect a common superclass HashSet classes = new HashSet(); for (int i = 0; i < array.length; i++) { classes.add((array[i] == null) ? null : array[i].getClass()); } if (classes.size() > 1) return; Class cl = (Class)classes.iterator().next(); if (Map.Entry.class.isAssignableFrom(cl)) { // check needed for protective cases like Predicated/Unmod map entrySet cl = Map.Entry.class; } a = (Object[])Array.newInstance(cl, 0); array = collection.toArray(a); assertEquals("toArray(Object[]) should return correct array type", a.getClass(), array.getClass()); assertEquals("type-specific toArrays should be equal", Arrays.asList(array), Arrays.asList(collection.toArray())); verify(); } /** * Tests <code>toString on a collection. */ public void testCollectionToString() { resetEmpty(); assertTrue("toString shouldn't return null", collection.toString() != null); resetFull(); assertTrue("toString shouldn't return null", collection.toString() != null); } /** * If isRemoveSupported() returns false, tests to see that remove * operations raise an UnsupportedOperationException. */ public void testUnsupportedRemove() { if (isRemoveSupported()) return; resetEmpty(); try { collection.clear(); fail("clear should raise UnsupportedOperationException"); } catch (UnsupportedOperationException e) { // expected } verify(); try { collection.remove(null); fail("remove should raise UnsupportedOperationException"); } catch (UnsupportedOperationException e) { // expected } verify(); try { collection.removeAll(null); fail("removeAll should raise UnsupportedOperationException"); } catch (UnsupportedOperationException e) { // expected } verify(); try { collection.retainAll(null); fail("removeAll should raise UnsupportedOperationException"); } catch (UnsupportedOperationException e) { // expected } verify(); resetFull(); try { Iterator iterator = collection.iterator(); iterator.next(); iterator.remove(); fail("iterator.remove should raise UnsupportedOperationException"); } catch (UnsupportedOperationException e) { // expected } verify(); } /** * Tests that the collection's iterator is fail-fast. */ public void testCollectionIteratorFailFast() { if (!isFailFastSupported()) return; if (isAddSupported()) { resetFull(); try { Iterator iter = collection.iterator(); Object o = getOtherElements()[0]; collection.add(o); confirmed.add(o); iter.next(); fail("next after add should raise ConcurrentModification"); } catch (ConcurrentModificationException e) { // expected } verify(); resetFull(); try { Iterator iter = collection.iterator(); collection.addAll(Arrays.asList(getOtherElements())); confirmed.addAll(Arrays.asList(getOtherElements())); iter.next(); fail("next after addAll should raise ConcurrentModification"); } catch (ConcurrentModificationException e) { // expected } verify(); } if (!isRemoveSupported()) return; resetFull(); try { Iterator iter = collection.iterator(); collection.clear(); iter.next(); fail("next after clear should raise ConcurrentModification"); } catch (ConcurrentModificationException e) { // expected } catch (NoSuchElementException e) { // (also legal given spec) } resetFull(); try { Iterator iter = collection.iterator(); collection.remove(getFullElements()[0]); iter.next(); fail("next after remove should raise ConcurrentModification"); } catch (ConcurrentModificationException e) { // expected } resetFull(); try { Iterator iter = collection.iterator(); List sublist = Arrays.asList(getFullElements()).subList(2,5); collection.removeAll(sublist); iter.next(); fail("next after removeAll should raise ConcurrentModification"); } catch (ConcurrentModificationException e) { // expected } resetFull(); try { Iterator iter = collection.iterator(); List sublist = Arrays.asList(getFullElements()).subList(2,5); collection.retainAll(sublist); iter.next(); fail("next after retainAll should raise ConcurrentModification"); } catch (ConcurrentModificationException e) { // expected } } public void testSerializeDeserializeThenCompare() throws Exception { Object obj = makeCollection(); if (obj instanceof Serializable && isTestSerialization()) { ByteArrayOutputStream buffer = new ByteArrayOutputStream(); ObjectOutputStream out = new ObjectOutputStream(buffer); out.writeObject(obj); out.close(); ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(buffer.toByteArray())); Object dest = in.readObject(); in.close(); if (isEqualsCheckable()) { assertEquals("obj != deserialize(serialize(obj)) - EMPTY Collection", obj, dest); } } obj = makeFullCollection(); if (obj instanceof Serializable && isTestSerialization()) { ByteArrayOutputStream buffer = new ByteArrayOutputStream(); ObjectOutputStream out = new ObjectOutputStream(buffer); out.writeObject(obj); out.close(); ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(buffer.toByteArray())); Object dest = in.readObject(); in.close(); if (isEqualsCheckable()) { assertEquals("obj != deserialize(serialize(obj)) - FULL Collection", obj, dest); } } } }

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