/*
 * Copyright 2009 the original author or authors.
 *
 * Licensed 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
 *
 *      http://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.gradle.api.internal.artifacts;

import org.gradle.api.artifacts.FileCollection;

import java.io.File;
import java.util.Arrays;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

/**
 * A {@link org.gradle.api.artifacts.FileCollection} which contains the union of the given source collections. Maintains
 * file ordering.
 */
public class UnionFileCollection extends AbstractFileCollection {
    private final List<FileCollection> sourceCollections;

    public UnionFileCollection(FileCollection... sourceCollections) {
        this.sourceCollections = Arrays.asList(sourceCollections);
    }

    public String getDisplayName() {
        return "file collection";
    }

    public Set<File> getFiles() {
        Set<File> files = new LinkedHashSet<File>();
        for (FileCollection collection : sourceCollections) {
            files.addAll(collection.getFiles());
        }
        return files;
    }
}
