/**
* Copyright © 2002 Instituto Superior Técnico
*
* This file is part of FenixEdu Academic.
*
* FenixEdu Academic is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* FenixEdu Academic is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with FenixEdu Academic. If not, see <http://www.gnu.org/licenses/>.
*/
package org.fenixedu.academic.util;
import java.io.Serializable;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;
import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.functors.AllPredicate;
import pt.ist.fenixframework.DomainObject;
public class CollectionFilter<T extends DomainObject> implements Serializable {
private final Comparator<T> comparator;
private Set<Predicate> predicates;
public Set<Predicate> getPredicates() {
return predicates;
}
public CollectionFilter() {
this.comparator = null;
}
public CollectionFilter(Set<Predicate> predicates) {
this(predicates, null);
}
public CollectionFilter(Predicate predicate) {
this(Collections.singleton(predicate), null);
}
public CollectionFilter(Set<Predicate> predicates, Comparator<T> comparator) {
this.comparator = comparator;
this.predicates = predicates;
}
public CollectionFilter(Predicate predicate, Comparator<T> comparator) {
this(Collections.singleton(predicate), comparator);
}
public Set<T> filter(Set<T> elements) {
Set<T> filtered;
if (comparator == null) {
filtered = new HashSet<T>();
} else {
filtered = new TreeSet<T>(comparator);
}
final Set<Predicate> predicates = getPredicates();
if (predicates == null || predicates.isEmpty()) {
filtered.addAll(elements);
return Collections.unmodifiableSet(filtered);
}
Predicate predicate;
if (predicates.size() == 1) {
predicate = predicates.iterator().next();
} else {
predicate = AllPredicate.getInstance(predicates);
}
for (T element : elements) {
if (predicate.evaluate(element)) {
filtered.add(element);
}
}
return Collections.unmodifiableSet(filtered);
}
}