Added get(object, index) method to CollectionUtils, deprecating index(-,-) methods.
git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@131235 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Phil Steitz
parent
03f4174238
commit
4b2811d1c4
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@ -1,5 +1,5 @@
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/*
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* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/CollectionUtils.java,v 1.44 2003/09/22 02:20:56 psteitz Exp $
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* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/CollectionUtils.java,v 1.45 2003/10/05 19:48:00 psteitz Exp $
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* ====================================================================
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*
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* The Apache Software License, Version 1.1
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@ -84,7 +84,7 @@ import org.apache.commons.collections.observed.ObservableCollection;
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* Provides utility methods and decorators for {@link Collection} instances.
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*
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* @since Commons Collections 1.0
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* @version $Revision: 1.44 $ $Date: 2003/09/22 02:20:56 $
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* @version $Revision: 1.45 $ $Date: 2003/10/05 19:48:00 $
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*
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* @author Rodney Waldhoff
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* @author Paul Jack
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@ -730,6 +730,8 @@ public class CollectionUtils {
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* @param idx the index to get
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* @throws IndexOutOfBoundsException
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* @throws ArrayIndexOutOfBoundsException
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*
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* @deprecated use {@link #get(Object, int)} instead
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*/
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public static Object index(Object obj, int idx) {
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return index(obj, new Integer(idx));
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@ -755,6 +757,8 @@ public class CollectionUtils {
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* @return the object at the specified index
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* @throws IndexOutOfBoundsException
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* @throws ArrayIndexOutOfBoundsException
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*
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* @deprecated use {@link #get(Object, int)} instead
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*/
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public static Object index(Object obj, Object index) {
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if(obj instanceof Map) {
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@ -814,6 +818,86 @@ public class CollectionUtils {
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return iterator;
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}
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/**
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* Returns the <code>index</code>-th value in <code>object</code>, throwing
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* <code>IndexOutOfBoundsException</code> if there is no such element or
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* <code>IllegalArgumentException</code> if <code>object</code> is not an
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* instance of one of the supported types.
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* <p>
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* The supported types, and associated semantics are:
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* <ul>
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* <li> Map -- the value returned is the <code>Map.Entry</code> in position
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* <code>index</code> in the map's <code>entrySet</code> iterator,
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* if there is such an entry.</li>
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* <li> List -- this method is equivalent to the list's get method.</li>
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* <li> Object Array -- the <code>index</code>-th array entry is returned,
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* if there is such an entry; otherwise an <code>ArrayIndexOutOfBoundsException</code>
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* is thrown.</li>
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* <li> Collection -- the value returned is the <code>index</code>-th object
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* returned by the collection's default iterator, if there is such an element.</li>
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* <li> Iterator or Enumeration -- the value returned is the
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* <code>index</code>-th object in the Iterator/Enumeration, if there
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* is such an element. The Iterator/Enumeration is advanced to
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* <code>index</code> (or to the end, if <code>index</code> exceeds the
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* number of entries) as a side effect of this method.</li>
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* </ul>
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*
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* @param object the object to get a value from
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* @param index the index to get
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* @return the object at the specified index
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* @throws IndexOutOfBoundsException
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* @throws IllegalArgumentException
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*/
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public static Object get(Object object, int index) {
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if (index < 0) {
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throw new IndexOutOfBoundsException("Index cannot be negative.");
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}
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if(object instanceof Map) {
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Map map = (Map)object;
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Iterator iterator = map.entrySet().iterator();
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return get(iterator, index);
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}
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else if(object instanceof List) {
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return ((List)object).get(index);
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}
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else if(object instanceof Object[]) {
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return ((Object[])object)[index];
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}
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else if(object instanceof Enumeration) {
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Enumeration enum = (Enumeration)object;
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while(enum.hasMoreElements()) {
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index--;
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if(index == -1) {
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return enum.nextElement();
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} else {
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enum.nextElement();
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}
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}
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throw new IndexOutOfBoundsException("Entry does not exist.");
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}
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else if(object instanceof Iterator) {
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return get((Iterator)object, index);
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}
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else if(object instanceof Collection) {
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Iterator iterator = ((Collection)object).iterator();
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return get(iterator, index);
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} else {
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throw new IllegalArgumentException("Unsupported object type.");
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}
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}
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private static Object get(Iterator iterator, int index) {
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while(iterator.hasNext()) {
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index--;
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if(index == -1) {
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return iterator.next();
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} else {
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iterator.next();
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}
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}
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throw new IndexOutOfBoundsException("Entry does not exist.");
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}
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/**
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* Returns an Iterator for the given object. Currently this method can handle
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* Iterator, Enumeration, Collection, Map, Object[] or array.
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@ -1,7 +1,7 @@
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/*
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* $Id: TestCollectionUtils.java,v 1.23 2003/10/02 22:14:29 scolebourne Exp $
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* $Revision: 1.23 $
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* $Date: 2003/10/02 22:14:29 $
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* $Id: TestCollectionUtils.java,v 1.24 2003/10/05 19:48:00 psteitz Exp $
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* $Revision: 1.24 $
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* $Date: 2003/10/05 19:48:00 $
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*
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* ====================================================================
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*
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@ -93,7 +93,7 @@ import org.apache.commons.collections.decorators.UnmodifiableCollection;
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* @author Stephen Colebourne
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* @author Phil Steitz
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*
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* @version $Revision: 1.23 $ $Date: 2003/10/02 22:14:29 $
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* @version $Revision: 1.24 $ $Date: 2003/10/05 19:48:00 $
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*/
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public class TestCollectionUtils extends TestCase {
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public TestCollectionUtils(String testName) {
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@ -594,6 +594,136 @@ public class TestCollectionUtils extends TestCase {
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assertTrue(test.equals(obj));
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}
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public void testGet() {
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// Unordered map, entries exist
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Map map = new HashMap();
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map.put("zeroKey", "zero");
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map.put("oneKey", "one");
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Object test = CollectionUtils.get(map, 0);
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assertTrue(((Map.Entry) test).getKey().equals("zeroKey"));
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assertTrue(((Map.Entry) test).getValue().equals("zero"));
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test = CollectionUtils.get(map, 1);
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assertTrue(((Map.Entry) test).getKey().equals("oneKey"));
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assertTrue(((Map.Entry) test).getValue().equals("one"));
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// Map index out of range
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try {
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test = CollectionUtils.get(map, 2);
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fail("Expecting IndexOutOfBoundsException.");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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try {
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test = CollectionUtils.get(map, -2);
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fail("Expecting IndexOutOfBoundsException.");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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// Sorted map, entries exist, should respect order
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SortedMap map2 = new TreeMap();
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map2.put("zeroKey", "zero");
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map2.put("oneKey", "one");
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test = CollectionUtils.get(map2, 1);
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assertTrue(((Map.Entry) test).getKey().equals("zeroKey"));
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assertTrue(((Map.Entry) test).getValue().equals("zero"));
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test = CollectionUtils.get(map2, 0);
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assertTrue(((Map.Entry) test).getKey().equals("oneKey"));
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assertTrue(((Map.Entry) test).getValue().equals("one"));
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// List, entry exists
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List list = new ArrayList();
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list.add("zero");
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list.add("one");
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test = CollectionUtils.get(list, 0);
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assertTrue(test.equals("zero"));
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test = CollectionUtils.get(list, 1);
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assertTrue(test.equals("one"));
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// list, non-existent entry -- IndexOutOfBoundsException
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try {
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test = CollectionUtils.index(list, 2);
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fail("Expecting IndexOutOfBoundsException");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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// Iterator, entry exists
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Iterator iterator = list.iterator();
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test = CollectionUtils.get(iterator,0);
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assertTrue(test.equals("zero"));
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iterator = list.iterator();
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test = CollectionUtils.get(iterator,1);
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assertTrue(test.equals("one"));
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// Iterator, non-existent entry
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try {
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test = CollectionUtils.get(iterator,3);
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fail("Expecting IndexOutOfBoundsException.");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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assertTrue(!iterator.hasNext());
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// Enumeration, entry exists
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Vector vector = new Vector(list);
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Enumeration enum = vector.elements();
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test = CollectionUtils.get(enum,0);
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assertTrue(test.equals("zero"));
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enum = vector.elements();
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test = CollectionUtils.get(enum,1);
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assertTrue(test.equals("one"));
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// Enumerator, non-existent entry
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try {
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test = CollectionUtils.get(enum,3);
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fail("Expecting IndexOutOfBoundsException.");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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assertTrue(!enum.hasMoreElements());
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// Collection, entry exists
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Bag bag = new HashBag();
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bag.add("element", 1);
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test = CollectionUtils.get(bag, 0);
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assertTrue(test.equals("element"));
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// Collection, non-existent entry
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try {
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test = CollectionUtils.get(bag, 1);
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fail("Expceting IndexOutOfBoundsException.");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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// Object array, entry exists
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Object[] objArray = new Object[2];
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objArray[0] = "zero";
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objArray[1] = "one";
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test = CollectionUtils.get(objArray,0);
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assertTrue(test.equals("zero"));
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test = CollectionUtils.get(objArray,1);
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assertTrue(test.equals("one"));
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// Object array, non-existent entry -- ArrayIndexOutOfBoundsException
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try {
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test = CollectionUtils.get(objArray,2);
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fail("Expecting ArrayIndexOutOfBoundsException.");
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} catch (ArrayIndexOutOfBoundsException ex) {
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// expected
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}
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// Invalid object
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Object obj = new Object();
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try {
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test = CollectionUtils.get(obj, 0);
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fail("Expecting IllegalArgumentException.");
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} catch (IllegalArgumentException e) {
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// expected
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}
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}
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private static Predicate EQUALS_TWO = new Predicate() {
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public boolean evaluate(Object input) {
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