Java tutorial
/* * Copyright 2016 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.changedetection.state; import com.google.common.base.Function; import com.google.common.collect.ImmutableMap; import com.google.common.collect.Maps; import java.util.Collection; import java.util.Map; import static org.gradle.internal.Cast.uncheckedCast; public class DefaultFileCollectionSnapshotterRegistry implements FileCollectionSnapshotterRegistry { private final Map<Class<?>, FileCollectionSnapshotter> snapshotters; public DefaultFileCollectionSnapshotterRegistry(Collection<FileCollectionSnapshotter> snapshotters) { this.snapshotters = ImmutableMap .copyOf(Maps.uniqueIndex(snapshotters, new Function<FileCollectionSnapshotter, Class<?>>() { @Override public Class<?> apply(FileCollectionSnapshotter snapshotter) { Class<? extends FileCollectionSnapshotter> registeredType = snapshotter.getRegisteredType(); Class<? extends FileCollectionSnapshotter> type = snapshotter.getClass(); if (!registeredType.isAssignableFrom(type)) { throw new IllegalArgumentException(String.format( "Snapshotter registered type '%s' must be a super-type of the actual snapshotter type '%s'", registeredType.getName(), type.getName())); } return registeredType; } })); } @Override public Collection<FileCollectionSnapshotter> getAllSnapshotters() { return snapshotters.values(); } @Override public <T> T getSnapshotter(Class<? extends T> type) { FileCollectionSnapshotter snapshotter = snapshotters.get(type); if (snapshotter == null) { throw new IllegalStateException( String.format("No snapshotter registered with type '%s'", type.getName())); } return uncheckedCast(snapshotter); } }