org.apache.tools.ant.types.resources.Intersect Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tools.ant.types.resources;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
/**
* ResourceCollection representing the intersection
* of multiple nested ResourceCollections.
* @since Ant 1.7
*/
public class Intersect extends BaseResourceCollectionContainer {
/**
* Calculate the intersection of the nested ResourceCollections.
* @return a Collection of Resources.
*/
@Override
protected Collection getCollection() {
List rcs = getResourceCollections();
int size = rcs.size();
if (size < 2) {
throw new BuildException(
"The intersection of %d resource %s is undefined.", size,
size == 1 ? "collection" : "collections");
}
final Function> toSet =
c -> c.stream().collect(Collectors.toSet());
Iterator rc = rcs.iterator();
Set s = new LinkedHashSet<>(toSet.apply(rc.next()));
rc.forEachRemaining(c -> s.retainAll(toSet.apply(c)));
return s;
}
}