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now throws an exception for comparisons on an empty chain and 

added no-op constructor


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@130665 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Morgan James Delagrange 2002-03-19 22:25:58 +00:00
parent fedb457600
commit 54c23b2da3
2 changed files with 80 additions and 6 deletions
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40
src/java/org/apache/commons/collections/comparators/ComparatorChain.java
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@ -1,7 +1,7 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/comparators/ComparatorChain.java,v 1.4 2002/03/04 19:18:56 morgand Exp $
* $Revision: 1.4 $
* $Date: 2002/03/04 19:18:56 $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/comparators/ComparatorChain.java,v 1.5 2002/03/19 22:25:51 morgand Exp $
* $Revision: 1.5 $
* $Date: 2002/03/19 22:25:51 $
*
* ====================================================================
*
@ -101,9 +101,19 @@ public class ComparatorChain implements Comparator,Serializable {
protected BitSet orderingBits = null;
// ComparatorChain is "locked" after the first time
// compare(Object,Object) is called)
// compare(Object,Object) is called
protected boolean isLocked = false;
/**
* Construct a ComparatorChain with no Comparators.
* You must add at least one Comparator before calling
* the compare(Object,Object) method, or an
* UnsupportedOperationException is thrown
*/
public ComparatorChain() {
this(new ArrayList(),new BitSet());
}
/**
* Construct a ComparatorChain with a single Comparator,
* sorting in the forward order
@ -274,11 +284,29 @@ public class ComparatorChain implements Comparator,Serializable {
}
}
public int compare(Object o1, Object o2) {
private void checkChainIntegrity() {
if (comparatorChain.size() == 0) {
throw new UnsupportedOperationException("ComparatorChains must contain at least one Comparator");
}
}
/**
* Perform comaparisons on the Objects as per
* Comparator.compare(o1,o2).
*
* @param o1 object 1
* @param o2 object 2
* @return -1, 0, or 1
* @exception UnsupportedOperationException
* if the ComparatorChain does not contain at least one
* Comparator
*/
public int compare(Object o1, Object o2) throws UnsupportedOperationException {
if (isLocked == false) {
checkChainIntegrity();
isLocked = true;
}
// iterate over all comparators in the chain
Iterator comparators = comparatorChain.iterator();
for (int comparatorIndex = 0; comparators.hasNext(); ++comparatorIndex) {

46
src/test/org/apache/commons/collections/comparators/TestComparatorChain.java
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@ -31,6 +31,52 @@ public class TestComparatorChain extends TestComparator {
return chain;
}
public void testNoopComparatorChain() {
ComparatorChain chain = new ComparatorChain();
Integer i1 = new Integer(4);
Integer i2 = new Integer(6);
chain.addComparator(new ComparableComparator());
int correctValue = i1.compareTo(i2);
assertTrue("Comparison returns the right order",chain.compare(i1,i2) == correctValue);
}
public void testBadNoopComparatorChain() {
ComparatorChain chain = new ComparatorChain();
Integer i1 = new Integer(4);
Integer i2 = new Integer(6);
try {
chain.compare(i1,i2);
fail("An exception should be thrown when a chain contains zero comparators.");
} catch (UnsupportedOperationException e) {
}
}
public void testListComparatorChain() {
List list = new LinkedList();
list.add(new ComparableComparator());
ComparatorChain chain = new ComparatorChain(list);
Integer i1 = new Integer(4);
Integer i2 = new Integer(6);
int correctValue = i1.compareTo(i2);
assertTrue("Comparison returns the right order",chain.compare(i1,i2) == correctValue);
}
public void testBadListComparatorChain() {
List list = new LinkedList();
ComparatorChain chain = new ComparatorChain(list);
Integer i1 = new Integer(4);
Integer i2 = new Integer(6);
try {
chain.compare(i1,i2);
fail("An exception should be thrown when a chain contains zero comparators.");
} catch (UnsupportedOperationException e) {
}
}
public List getComparableObjectsOrdered() {
List list = new LinkedList();
// this is the correct order assuming a