Java tutorial
/* * Copyright (C) 2016 The Android Open Source Project * * 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 com.android.builder.internal.packaging.zip.utils; import com.google.common.io.ByteSource; import java.io.Closeable; import java.io.IOException; /** * Byte source that can be closed. Closing a byte source allows releasing any resources associated * with it. This should not be confused with closing streams. For example, {@link ByteTracker} uses * {@code CloseableByteSources} to know when the data associated with the byte source can be * released. */ public abstract class CloseableByteSource extends ByteSource implements Closeable { /** * Has the source been closed? */ private boolean mClosed; /** * Creates a new byte source. */ public CloseableByteSource() { mClosed = false; } @Override public final synchronized void close() throws IOException { if (mClosed) { return; } try { innerClose(); } finally { mClosed = true; } } /** * Closes the by source. This method is only invoked once, even if {@link #close()} is * called multiple times * @throws IOException failed to close */ protected abstract void innerClose() throws IOException; }