com.sun.tools.xjc.reader.gbind.ElementSets Maven / Gradle / Ivy
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package com.sun.tools.xjc.reader.gbind;
import java.util.LinkedHashSet;
/**
* Factory methods for {@link ElementSet}.
*
* @author Kohsuke Kawaguchi
*/
public final class ElementSets {
/**
* Returns an union of two {@link ElementSet}s.
*
* This method performs better if lhs is bigger than rhs
*/
public static ElementSet union(ElementSet lhs, ElementSet rhs) {
if(lhs.contains(rhs))
return lhs;
if(lhs==ElementSet.EMPTY_SET)
return rhs;
if(rhs==ElementSet.EMPTY_SET)
return lhs;
return new MultiValueSet(lhs,rhs);
}
/**
* {@link ElementSet} that has multiple {@link Element}s in it.
*
* This isn't particularly efficient or anything, but it will do for now.
*/
private static final class MultiValueSet extends LinkedHashSet implements ElementSet {
public MultiValueSet(ElementSet lhs, ElementSet rhs) {
addAll(lhs);
addAll(rhs);
// not that anything will break with size==1 MultiValueSet,
// but it does suggest that we are missing an easy optimization
assert size()>1;
}
private void addAll(ElementSet lhs) {
if(lhs instanceof MultiValueSet) {
super.addAll((MultiValueSet)lhs);
} else {
for (Element e : lhs)
add(e);
}
}
public boolean contains(ElementSet rhs) {
// this isn't complete but sound
return super.contains(rhs) || rhs==ElementSet.EMPTY_SET;
}
public void addNext(Element element) {
for (Element e : this)
e.addNext(element);
}
}
}