/*
    * Copyright (C) 2007 The Guava 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 com.google.common.io;
  
  import com.google.common.annotations.Beta;
  import com.google.common.annotations.VisibleForTesting;
  
  import java.io.Closeable;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.annotation.Nullable;
  
  /**
   * Utility methods for working with {@link Closeable} objects.
   *
   * @author Michael Lancaster
   * @since 1.0
   */
  @Beta
  public final class Closeables {
    @VisibleForTesting static final Logger logger
        = Logger.getLogger(Closeables.class.getName());
  
    private Closeables() {}
  
    /**
     * Closes a {@link Closeable}, with control over whether an {@code IOException} may be thrown.
     * This is primarily useful in a finally block, where a thrown exception needs to be logged but
     * not propagated (otherwise the original exception will be lost).
     *
     * <p>If {@code swallowIOException} is true then we never throw {@code IOException} but merely log
     * it.
     *
     * <p>Example: <pre>   {@code
     *
     *   public void useStreamNicely() throws IOException {
     *     SomeStream stream = new SomeStream("foo");
     *     boolean threw = true;
     *     try {
     *       // ... code which does something with the stream ...
     *       threw = false;
     *     } finally {
     *       // If an exception occurs, rethrow it only if threw==false:
     *       Closeables.close(stream, threw);
     *     }
     *   }}</pre>
     *
     * @param closeable the {@code Closeable} object to be closed, or null, in which case this method
     *     does nothing
     * @param swallowIOException if true, don't propagate IO exceptions thrown by the {@code close}
     *     methods
     * @throws IOException if {@code swallowIOException} is false and {@code close} throws an
     *     {@code IOException}.
     */
    public static void close(@Nullable Closeable closeable,
        boolean swallowIOException) throws IOException {
      if (closeable == null) {
        return;
      }
      try {
        closeable.close();
      } catch (IOException e) {
        if (swallowIOException) {
          logger.log(Level.WARNING,
              "IOException thrown while closing Closeable.", e);
        } else {
          throw e;
        }
      }
    }
  
    /**
     * Closes the given {@link InputStream}, logging any {@code IOException} that's thrown rather
     * than propagating it.
     *
     * <p>While it's not safe in the general case to ignore exceptions that are thrown when closing
     * an I/O resource, it should generally be safe in the case of a resource that's being used only
     * for reading, such as an {@code InputStream}. Unlike with writable resources, there's no
     * chance that a failure that occurs when closing the stream indicates a meaningful problem such
     * as a failure to flush all bytes to the underlying resource.
     *
    * @param inputStream the input stream to be closed, or {@code null} in which case this method
    *     does nothing
    * @since 17.0
    */
   public static void closeQuietly(@Nullable InputStream inputStream) {
     try {
       close(inputStream, true);
     } catch (IOException impossible) {
       throw new AssertionError(impossible);
     }
   }
 
   /**
    * Closes the given {@link Reader}, logging any {@code IOException} that's thrown rather than
    * propagating it.
    *
    * <p>While it's not safe in the general case to ignore exceptions that are thrown when closing
    * an I/O resource, it should generally be safe in the case of a resource that's being used only
    * for reading, such as a {@code Reader}. Unlike with writable resources, there's no chance that
    * a failure that occurs when closing the reader indicates a meaningful problem such as a failure
    * to flush all bytes to the underlying resource.
    *
    * @param reader the reader to be closed, or {@code null} in which case this method does nothing
    * @since 17.0
    */
   public static void closeQuietly(@Nullable Reader reader) {
     try {
       close(reader, true);
     } catch (IOException impossible) {
       throw new AssertionError(impossible);
     }
   }
 }