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[COLLECTIONS-427] Revert performance improvement and add clarifying javadoc wrt runtime complexity. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1655062 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2015-01-27 15:09:02 +00:00
parent a3b3b74ec6
commit 2db7aa771a
3 changed files with 21 additions and 42 deletions
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4
src/changes/changes.xml
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@ -22,6 +22,10 @@
<body>
<release version="4.1" date="TBD" description="">
<action issue="COLLECTIONS-427" dev="tn" type="fix">
Reverted performance improvement for "SetUniqueList#retainAll(Collection)"
introduced in 4.0. Added clarifying javadoc wrt runtime complexity instead.
</action>
<action issue="COLLECTIONS-426" dev="tn" type="fix">
Reverted performance improvement for "ListOrderedSet#retainAll(Collection)"
introduced in 4.0. Added clarifying javadoc wrt runtime complexity instead.

33
src/main/java/org/apache/commons/collections4/list/SetUniqueList.java
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@ -25,9 +25,9 @@ import java.util.ListIterator;
import java.util.Set;
import org.apache.commons.collections4.ListUtils;
import org.apache.commons.collections4.set.UnmodifiableSet;
import org.apache.commons.collections4.iterators.AbstractIteratorDecorator;
import org.apache.commons.collections4.iterators.AbstractListIteratorDecorator;
import org.apache.commons.collections4.set.UnmodifiableSet;
/**
* Decorates a <code>List</code> to ensure that no duplicates are present much
@ -251,27 +251,28 @@ public class SetUniqueList<E> extends AbstractSerializableListDecorator<E> {
return result;
}
/**
* {@inheritDoc}
* <p>
* This implementation iterates over the elements of this list, checking
* each element in turn to see if it's contained in <code>coll</code>.
* If it's not contained, it's removed from this list. As a consequence,
* it is advised to use a collection type for <code>coll</code> that provides
* a fast (e.g. O(1)) implementation of {@link Collection#contains(Object)}.
*/
@Override
public boolean retainAll(final Collection<?> coll) {
final Set<Object> setRetainAll = new HashSet<Object>();
for (final Object next : coll) {
if (set.contains(next)) {
setRetainAll.add(next);
}
}
if (setRetainAll.size() == set.size()) {
boolean result = set.retainAll(coll);
if (result == false) {
return false;
}
if (setRetainAll.size() == 0) {
clear();
if (set.size() == 0) {
super.clear();
} else {
for (final Iterator<E> it = iterator(); it.hasNext();) {
if (!setRetainAll.contains(it.next())) {
it.remove();
}
}
// use the set as parameter for the call to retainAll to improve performance
super.retainAll(set);
}
return true;
return result;
}
@Override

26
src/test/java/org/apache/commons/collections4/list/SetUniqueListTest.java
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@ -561,32 +561,6 @@ public class SetUniqueListTest<E> extends AbstractListTest<E> {
assertTrue(uniqueList.contains(Integer.valueOf(8)));
}
/*
* test case for https://issues.apache.org/jira/browse/COLLECTIONS-427
*/
@SuppressWarnings("boxing") // OK in test code
public void testRetainAllCollections427() {
final int size = 50000;
final ArrayList<Integer> list = new ArrayList<Integer>();
for (int i = 0; i < size; i++) {
list.add(i);
}
final SetUniqueList<Integer> uniqueList = SetUniqueList.setUniqueList(list);
final ArrayList<Integer> toRetain = new ArrayList<Integer>();
for (int i = size; i < 2*size; i++) {
toRetain.add(i);
}
final long start = System.currentTimeMillis();
uniqueList.retainAll(toRetain);
final long stop = System.currentTimeMillis();
// make sure retainAll completes under 5 seconds
// TODO if test is migrated to JUnit 4, add a Timeout rule.
// http://kentbeck.github.com/junit/javadoc/latest/org/junit/rules/Timeout.html
assertTrue(stop - start < 5000);
}
public void testSetCollections444() {
final SetUniqueList<Integer> lset = new SetUniqueList<Integer>(new ArrayList<Integer>(), new HashSet<Integer>());