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 2003-10-05 19:48:00 +00:00
parent 03f4174238
commit 4b2811d1c4
2 changed files with 220 additions and 6 deletions

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@ -1,5 +1,5 @@
/*
* $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 $
* $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 $
* ====================================================================
*
* The Apache Software License, Version 1.1
@ -84,7 +84,7 @@ import org.apache.commons.collections.observed.ObservableCollection;
* Provides utility methods and decorators for {@link Collection} instances.
*
* @since Commons Collections 1.0
* @version $Revision: 1.44 $ $Date: 2003/09/22 02:20:56 $
* @version $Revision: 1.45 $ $Date: 2003/10/05 19:48:00 $
*
* @author Rodney Waldhoff
* @author Paul Jack
@ -730,6 +730,8 @@ public class CollectionUtils {
* @param idx the index to get
* @throws IndexOutOfBoundsException
* @throws ArrayIndexOutOfBoundsException
*
* @deprecated use {@link #get(Object, int)} instead
*/
public static Object index(Object obj, int idx) {
return index(obj, new Integer(idx));
@ -755,6 +757,8 @@ public class CollectionUtils {
* @return the object at the specified index
* @throws IndexOutOfBoundsException
* @throws ArrayIndexOutOfBoundsException
*
* @deprecated use {@link #get(Object, int)} instead
*/
public static Object index(Object obj, Object index) {
if(obj instanceof Map) {
@ -813,6 +817,86 @@ public class CollectionUtils {
}
return iterator;
}
/**
* Returns the <code>index</code>-th value in <code>object</code>, throwing
* <code>IndexOutOfBoundsException</code> if there is no such element or
* <code>IllegalArgumentException</code> if <code>object</code> is not an
* instance of one of the supported types.
* <p>
* The supported types, and associated semantics are:
* <ul>
* <li> Map -- the value returned is the <code>Map.Entry</code> in position
* <code>index</code> in the map's <code>entrySet</code> iterator,
* if there is such an entry.</li>
* <li> List -- this method is equivalent to the list's get method.</li>
* <li> Object Array -- the <code>index</code>-th array entry is returned,
* if there is such an entry; otherwise an <code>ArrayIndexOutOfBoundsException</code>
* is thrown.</li>
* <li> Collection -- the value returned is the <code>index</code>-th object
* returned by the collection's default iterator, if there is such an element.</li>
* <li> Iterator or Enumeration -- the value returned is the
* <code>index</code>-th object in the Iterator/Enumeration, if there
* is such an element. The Iterator/Enumeration is advanced to
* <code>index</code> (or to the end, if <code>index</code> exceeds the
* number of entries) as a side effect of this method.</li>
* </ul>
*
* @param object the object to get a value from
* @param index the index to get
* @return the object at the specified index
* @throws IndexOutOfBoundsException
* @throws IllegalArgumentException
*/
public static Object get(Object object, int index) {
if (index < 0) {
throw new IndexOutOfBoundsException("Index cannot be negative.");
}
if(object instanceof Map) {
Map map = (Map)object;
Iterator iterator = map.entrySet().iterator();
return get(iterator, index);
}
else if(object instanceof List) {
return ((List)object).get(index);
}
else if(object instanceof Object[]) {
return ((Object[])object)[index];
}
else if(object instanceof Enumeration) {
Enumeration enum = (Enumeration)object;
while(enum.hasMoreElements()) {
index--;
if(index == -1) {
return enum.nextElement();
} else {
enum.nextElement();
}
}
throw new IndexOutOfBoundsException("Entry does not exist.");
}
else if(object instanceof Iterator) {
return get((Iterator)object, index);
}
else if(object instanceof Collection) {
Iterator iterator = ((Collection)object).iterator();
return get(iterator, index);
} else {
throw new IllegalArgumentException("Unsupported object type.");
}
}
private static Object get(Iterator iterator, int index) {
while(iterator.hasNext()) {
index--;
if(index == -1) {
return iterator.next();
} else {
iterator.next();
}
}
throw new IndexOutOfBoundsException("Entry does not exist.");
}
/**
* Returns an Iterator for the given object. Currently this method can handle

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@ -1,7 +1,7 @@
/*
* $Id: TestCollectionUtils.java,v 1.23 2003/10/02 22:14:29 scolebourne Exp $
* $Revision: 1.23 $
* $Date: 2003/10/02 22:14:29 $
* $Id: TestCollectionUtils.java,v 1.24 2003/10/05 19:48:00 psteitz Exp $
* $Revision: 1.24 $
* $Date: 2003/10/05 19:48:00 $
*
* ====================================================================
*
@ -93,7 +93,7 @@ import org.apache.commons.collections.decorators.UnmodifiableCollection;
* @author Stephen Colebourne
* @author Phil Steitz
*
* @version $Revision: 1.23 $ $Date: 2003/10/02 22:14:29 $
* @version $Revision: 1.24 $ $Date: 2003/10/05 19:48:00 $
*/
public class TestCollectionUtils extends TestCase {
public TestCollectionUtils(String testName) {
@ -593,6 +593,136 @@ public class TestCollectionUtils extends TestCase {
test = CollectionUtils.index(obj, obj);
assertTrue(test.equals(obj));
}
public void testGet() {
// Unordered map, entries exist
Map map = new HashMap();
map.put("zeroKey", "zero");
map.put("oneKey", "one");
Object test = CollectionUtils.get(map, 0);
assertTrue(((Map.Entry) test).getKey().equals("zeroKey"));
assertTrue(((Map.Entry) test).getValue().equals("zero"));
test = CollectionUtils.get(map, 1);
assertTrue(((Map.Entry) test).getKey().equals("oneKey"));
assertTrue(((Map.Entry) test).getValue().equals("one"));
// Map index out of range
try {
test = CollectionUtils.get(map, 2);
fail("Expecting IndexOutOfBoundsException.");
} catch (IndexOutOfBoundsException e) {
// expected
}
try {
test = CollectionUtils.get(map, -2);
fail("Expecting IndexOutOfBoundsException.");
} catch (IndexOutOfBoundsException e) {
// expected
}
// Sorted map, entries exist, should respect order
SortedMap map2 = new TreeMap();
map2.put("zeroKey", "zero");
map2.put("oneKey", "one");
test = CollectionUtils.get(map2, 1);
assertTrue(((Map.Entry) test).getKey().equals("zeroKey"));
assertTrue(((Map.Entry) test).getValue().equals("zero"));
test = CollectionUtils.get(map2, 0);
assertTrue(((Map.Entry) test).getKey().equals("oneKey"));
assertTrue(((Map.Entry) test).getValue().equals("one"));
// List, entry exists
List list = new ArrayList();
list.add("zero");
list.add("one");
test = CollectionUtils.get(list, 0);
assertTrue(test.equals("zero"));
test = CollectionUtils.get(list, 1);
assertTrue(test.equals("one"));
// list, non-existent entry -- IndexOutOfBoundsException
try {
test = CollectionUtils.index(list, 2);
fail("Expecting IndexOutOfBoundsException");
} catch (IndexOutOfBoundsException e) {
// expected
}
// Iterator, entry exists
Iterator iterator = list.iterator();
test = CollectionUtils.get(iterator,0);
assertTrue(test.equals("zero"));
iterator = list.iterator();
test = CollectionUtils.get(iterator,1);
assertTrue(test.equals("one"));
// Iterator, non-existent entry
try {
test = CollectionUtils.get(iterator,3);
fail("Expecting IndexOutOfBoundsException.");
} catch (IndexOutOfBoundsException e) {
// expected
}
assertTrue(!iterator.hasNext());
// Enumeration, entry exists
Vector vector = new Vector(list);
Enumeration enum = vector.elements();
test = CollectionUtils.get(enum,0);
assertTrue(test.equals("zero"));
enum = vector.elements();
test = CollectionUtils.get(enum,1);
assertTrue(test.equals("one"));
// Enumerator, non-existent entry
try {
test = CollectionUtils.get(enum,3);
fail("Expecting IndexOutOfBoundsException.");
} catch (IndexOutOfBoundsException e) {
// expected
}
assertTrue(!enum.hasMoreElements());
// Collection, entry exists
Bag bag = new HashBag();
bag.add("element", 1);
test = CollectionUtils.get(bag, 0);
assertTrue(test.equals("element"));
// Collection, non-existent entry
try {
test = CollectionUtils.get(bag, 1);
fail("Expceting IndexOutOfBoundsException.");
} catch (IndexOutOfBoundsException e) {
// expected
}
// Object array, entry exists
Object[] objArray = new Object[2];
objArray[0] = "zero";
objArray[1] = "one";
test = CollectionUtils.get(objArray,0);
assertTrue(test.equals("zero"));
test = CollectionUtils.get(objArray,1);
assertTrue(test.equals("one"));
// Object array, non-existent entry -- ArrayIndexOutOfBoundsException
try {
test = CollectionUtils.get(objArray,2);
fail("Expecting ArrayIndexOutOfBoundsException.");
} catch (ArrayIndexOutOfBoundsException ex) {
// expected
}
// Invalid object
Object obj = new Object();
try {
test = CollectionUtils.get(obj, 0);
fail("Expecting IllegalArgumentException.");
} catch (IllegalArgumentException e) {
// expected
}
}
private static Predicate EQUALS_TWO = new Predicate() {