Java tutorial
//package com.java2s; /** * Licensed to the Austrian Association for Software Tool Integration (AASTI) * under one or more contributor license agreements. See the NOTICE file * distributed with this work for additional information regarding copyright * ownership. The AASTI 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 * * 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. */ import java.util.Collection; import com.google.common.base.Function; import com.google.common.base.Predicate; import com.google.common.collect.Collections2; public class Main { /** * provides a view to the given collection, that only contains objects that are instances of the given clazz. It * uses the guava-methods {@link Collections2#filter(Collection, Predicate)} and * {@link Collections2#transform(Collection, Function)}. * * The returned collection is immutable. */ public static <TargetType> Collection<TargetType> filterCollectionByClass(Collection<?> source, final Class<TargetType> clazz) { Collection<?> filtered = Collections2.filter(source, new Predicate<Object>() { @Override public boolean apply(Object input) { return clazz.isInstance(input); } }); return Collections2.transform(filtered, new Function<Object, TargetType>() { @SuppressWarnings("unchecked") @Override public TargetType apply(Object input) { return (TargetType) input; } }); } }