| /* |
| * Copyright 2016, Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package io.grpc.internal; |
| |
| import java.util.HashSet; |
| |
| import javax.annotation.concurrent.NotThreadSafe; |
| |
| /** |
| * Aggregates the in-use state of a set of objects. |
| */ |
| @NotThreadSafe |
| abstract class InUseStateAggregator2<T> { |
| |
| private final HashSet<T> inUseObjects = new HashSet<T>(); |
| |
| /** |
| * Update the in-use state of an object. Initially no object is in use. |
| * |
| * <p>This may call into {@link #handleInUse} or {@link #handleNotInUse} when appropriate. |
| */ |
| final void updateObjectInUse(T object, boolean inUse) { |
| int origSize = inUseObjects.size(); |
| if (inUse) { |
| inUseObjects.add(object); |
| if (origSize == 0) { |
| handleInUse(); |
| } |
| } else { |
| boolean removed = inUseObjects.remove(object); |
| if (removed && origSize == 1) { |
| handleNotInUse(); |
| } |
| } |
| } |
| |
| final boolean isInUse() { |
| return !inUseObjects.isEmpty(); |
| } |
| |
| /** |
| * Called when the aggregated in-use state has changed to true, which means at least one object is |
| * in use. |
| */ |
| abstract void handleInUse(); |
| |
| /** |
| * Called when the aggregated in-use state has changed to false, which means no object is in use. |
| */ |
| abstract void handleNotInUse(); |
| } |