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Enhance OrderedSet to support List like functions 

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@131172 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne 2003-09-20 16:57:47 +00:00
parent 460a6e5b8b
commit c3c28e3dae
2 changed files with 173 additions and 9 deletions
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104
src/java/org/apache/commons/collections/decorators/OrderedSet.java
View File

@ -1,5 +1,5 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/decorators/Attic/OrderedSet.java,v 1.1 2003/09/09 22:28:35 scolebourne Exp $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/decorators/Attic/OrderedSet.java,v 1.2 2003/09/20 16:57:47 scolebourne Exp $
* ====================================================================
*
* The Apache Software License, Version 1.1
@ -59,6 +59,8 @@ package org.apache.commons.collections.decorators;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
@ -67,13 +69,20 @@ import java.util.Set;
* Decorates a <code>Set</code> to ensure that the order of addition
* is retained and used by the iterator.
* <p>
* If an object is added to the Set for a second time, it will remain in the
* If an object is added to the set for a second time, it will remain in the
* original position in the iteration.
* The order can be observed from the set via the iterator or toArray methods.
* <p>
* The order can be observed via the iterator or toArray methods.
* The OrderedSet also has various useful direct methods. These include many
* from <code>List</code>, such as <code>get(int)</code>, <code>remove(int)</code>
* and <code>indexOf(int)</code>. An unmodifiable <code>List</code> view of
* the set can be obtained via <code>asList()</code>.
* <p>
* This class cannot implement the <code>List</code> interface directly as
* various interface methods (notably equals/hashCode) are incompatable with a set.
*
* @since Commons Collections 3.0
* @version $Revision: 1.1 $ $Date: 2003/09/09 22:28:35 $
* @version $Revision: 1.2 $ $Date: 2003/09/20 16:57:47 $
*
* @author Stephen Colebourne
* @author Henning P. Schmiedehausen
@ -81,18 +90,35 @@ import java.util.Set;
public class OrderedSet extends AbstractSetDecorator implements Set {
/** Internal list to hold the sequence of objects */
protected final List setOrder = new ArrayList();
protected final List setOrder;
/**
* Factory method to create an ordered set.
* <p>
* An <code>ArrayList</code> is used to retain order.
*
* @param set the set to decorate, must not be null
* @throws IllegalArgumentException if set is null
*/
public static Set decorate(Set set) {
public static OrderedSet decorate(Set set) {
return new OrderedSet(set);
}
/**
* Factory method to create an ordered set using the supplied list to retain order.
* <p>
* A <code>HashSet</code> is used for the set behaviour.
*
* @param list the list to decorate, must not be null
* @throws IllegalArgumentException if set is null
*/
public static OrderedSet decorate(List list) {
Set set = new HashSet(list);
list.retainAll(set);
return new OrderedSet(set, list);
}
/**
* Constructor that wraps (not copies).
*
@ -101,7 +127,34 @@ public class OrderedSet extends AbstractSetDecorator implements Set {
*/
protected OrderedSet(Set set) {
super(set);
setOrder.addAll(set);
setOrder = new ArrayList(set);
}
/**
* Constructor that wraps (not copies) the Set and specifies the list to use.
* <p>
* The set and list must both be correctly initialised to the same elements.
*
* @param set the set to decorate, must not be null
* @param list the list to decorate, must not be null
* @throws IllegalArgumentException if set or list is null
*/
protected OrderedSet(Set set, List list) {
super(set);
if (list == null) {
throw new IllegalArgumentException("List must not be null");
}
setOrder = list;
}
//-----------------------------------------------------------------------
/**
* Gets an unmodifiable view of the order of the Set.
*
* @return an unmodifiable list view
*/
public List asList() {
return Collections.unmodifiableList(setOrder);
}
//-----------------------------------------------------------------------
@ -175,6 +228,43 @@ public class OrderedSet extends AbstractSetDecorator implements Set {
return setOrder.toArray(a);
}
//-----------------------------------------------------------------------
public Object get(int index) {
return setOrder.get(index);
}
public int indexOf(Object object) {
return setOrder.indexOf(object);
}
public void add(int index, Object object) {
if (contains(object) == false) {
collection.add(object);
setOrder.add(index, object);
}
}
public boolean addAll(int index, Collection coll) {
boolean changed = false;
for (Iterator it = coll.iterator(); it.hasNext();) {
Object object = (Object) it.next();
if (contains(object) == false) {
collection.add(object);
setOrder.add(index, object);
index++;
changed = true;
}
}
return changed;
}
public Object remove(int index) {
Object obj = setOrder.remove(index);
remove(obj);
return obj;
}
//-----------------------------------------------------------------------
/**
* Internal iterator handle remove.
*/

78
src/test/org/apache/commons/collections/decorators/TestOrderedSet.java
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@ -1,5 +1,5 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/decorators/Attic/TestOrderedSet.java,v 1.1 2003/09/09 22:28:36 scolebourne Exp $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/decorators/Attic/TestOrderedSet.java,v 1.2 2003/09/20 16:57:47 scolebourne Exp $
* ====================================================================
*
* The Apache Software License, Version 1.1
@ -57,8 +57,10 @@
*/
package org.apache.commons.collections.decorators;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import junit.framework.Test;
@ -71,7 +73,7 @@ import org.apache.commons.collections.TestSet;
* implementation.
*
* @since Commons Collections 3.0
* @version $Revision: 1.1 $ $Date: 2003/09/09 22:28:36 $
* @version $Revision: 1.2 $ $Date: 2003/09/20 16:57:47 $
*
* @author Henning P. Schmiedehausen
* @author Stephen Colebourne
@ -136,4 +138,76 @@ public class TestOrderedSet extends TestSet {
}
}
private static final Integer ZERO = new Integer(0);
private static final Integer ONE = new Integer(1);
private static final Integer TWO = new Integer(2);
private static final Integer THREE = new Integer(3);
public void testListAddRemove() {
OrderedSet set = (OrderedSet) makeEmptySet();
List view = set.asList();
set.add(ZERO);
set.add(ONE);
set.add(TWO);
assertEquals(3, set.size());
assertSame(ZERO, set.get(0));
assertSame(ONE, set.get(1));
assertSame(TWO, set.get(2));
assertEquals(3, view.size());
assertSame(ZERO, view.get(0));
assertSame(ONE, view.get(1));
assertSame(TWO, view.get(2));
assertEquals(0, set.indexOf(ZERO));
assertEquals(1, set.indexOf(ONE));
assertEquals(2, set.indexOf(TWO));
set.remove(1);
assertEquals(2, set.size());
assertSame(ZERO, set.get(0));
assertSame(TWO, set.get(1));
assertEquals(2, view.size());
assertSame(ZERO, view.get(0));
assertSame(TWO, view.get(1));
}
public void testListAddIndexed() {
OrderedSet set = (OrderedSet) makeEmptySet();
List view = set.asList();
set.add(ZERO);
set.add(TWO);
set.add(1, ONE);
assertEquals(3, set.size());
assertSame(ZERO, set.get(0));
assertSame(ONE, set.get(1));
assertSame(TWO, set.get(2));
set.add(0, ONE);
assertEquals(3, set.size());
assertSame(ZERO, set.get(0));
assertSame(ONE, set.get(1));
assertSame(TWO, set.get(2));
List list = new ArrayList();
list.add(ZERO);
list.add(TWO);
set.addAll(0, list);
assertEquals(3, set.size());
assertSame(ZERO, set.get(0));
assertSame(ONE, set.get(1));
assertSame(TWO, set.get(2));
list.add(0, THREE); // list = [3,0,2]
set.remove(TWO); // set = [0,1]
set.addAll(1, list);
assertEquals(4, set.size());
assertSame(ZERO, set.get(0));
assertSame(THREE, set.get(1));
assertSame(TWO, set.get(2));
assertSame(ONE, set.get(3));
}
}