11d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert/* 21d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Copyright (C) 2007 The Guava Authors 31d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 41d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Licensed under the Apache License, Version 2.0 (the "License"); 51d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * you may not use this file except in compliance with the License. 61d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * You may obtain a copy of the License at 71d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 81d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * http://www.apache.org/licenses/LICENSE-2.0 91d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 101d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Unless required by applicable law or agreed to in writing, software 111d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * distributed under the License is distributed on an "AS IS" BASIS, 121d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 131d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * See the License for the specific language governing permissions and 141d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * limitations under the License. 151d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 161d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 171d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertpackage com.google.common.io; 181d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 191d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport com.google.common.collect.Sets; 201d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 211d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport java.io.IOException; 221d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport java.util.Set; 231d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 241d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert/** 251d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * The purpose of the CheckCloseSupplier is to report when all closeable objects 261d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * supplied by the delegate supplier are closed. To do this, the factory method 271d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * returns a decorated version of the {@code delegate} supplied in the 281d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * constructor. The decoration mechanism is left up to the subclass via the 291d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * abstract {@link #wrap} method. 301d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 311d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * <p>The decorated object returned from {@link #wrap} should ideally override 321d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * its {@code close} method to not only call {@code super.close()} but to also 331d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * call {@code callback.delegateClosed()}. 341d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 351d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @author Chris Nokleberg 361d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 371d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertabstract class CheckCloseSupplier<T> { 381d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private final Set<Callback> open = Sets.newHashSet(); 391d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 401d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert abstract static class Input<T> extends CheckCloseSupplier<T> 411d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert implements InputSupplier<T> { 421d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private final InputSupplier<? extends T> delegate; 431d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 441d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public Input(InputSupplier<? extends T> delegate) { 451d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert this.delegate = delegate; 461d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 471d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 481d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public T getInput() throws IOException { 491d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return wrap(delegate.getInput(), newCallback()); 501d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 511d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 521d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 531d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert abstract static class Output<T> extends CheckCloseSupplier<T> 541d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert implements OutputSupplier<T> { 551d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private final OutputSupplier<? extends T> delegate; 561d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 571d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public Output(OutputSupplier<? extends T> delegate) { 581d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert this.delegate = delegate; 591d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 601d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 611d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public T getOutput() throws IOException { 621d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return wrap(delegate.getOutput(), newCallback()); 631d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 641d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 651d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 661d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public final class Callback { 671d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public void delegateClosed() { 681d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert open.remove(this); 691d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 701d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 711d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 721d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert protected Callback newCallback() { 731d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert Callback callback = new Callback(); 741d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert open.add(callback); 751d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return callback; 761d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 771d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 781d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 791d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Subclasses should wrap the given object and call 801d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * {@link Callback#delegateClosed} when the close method of the delegate is 811d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * called, to inform the supplier that the underlying 821d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * {@code Closeable} is not longer open. 831d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 841d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @param object the object to wrap. 851d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @param callback the object that the wrapper should call to signal that the 861d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 871d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert protected abstract T wrap(T object, Callback callback); 881d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 891d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** Returns true if all the closeables have been closed closed */ 901d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public boolean areClosed() { 911d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return open.isEmpty(); 921d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 931d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert} 94