/*
 * 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 java.io.Flushable;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.google.common.annotations.Beta;

/**
 * Utility methods for working with {@link Flushable} objects.
 *
 * @author Michael Lancaster
 * @since 1.0
 */
@Beta
public final class Flushables {
	private static final Logger logger = Logger.getLogger(Flushables.class.getName());

	private Flushables() {
	}

	/**
	 * Flush a {@link Flushable}, with control over whether an {@code IOException}
	 * may be thrown.
	 *
	 * <p>
	 * If {@code swallowIOException} is true, then we don't rethrow
	 * {@code IOException}, but merely log it.
	 *
	 * @param flushable          the {@code Flushable} object to be flushed.
	 * @param swallowIOException if true, don't propagate IO exceptions thrown by
	 *                           the {@code flush} method
	 * @throws IOException if {@code swallowIOException} is false and
	 *                     {@link Flushable#flush} throws an {@code IOException}.
	 * @see Closeables#close
	 */
	public static void flush(Flushable flushable, boolean swallowIOException) throws IOException {
		try {
			flushable.flush();
		} catch (IOException e) {
			if (swallowIOException) {
				logger.log(Level.WARNING, "IOException thrown while flushing Flushable.", e);
			} else {
				throw e;
			}
		}
	}

	/**
	 * Equivalent to calling {@code flush(flushable, true)}, but with no
	 * {@code IOException} in the signature.
	 *
	 * @param flushable the {@code Flushable} object to be flushed.
	 */
	public static void flushQuietly(Flushable flushable) {
		try {
			flush(flushable, true);
		} catch (IOException e) {
			logger.log(Level.SEVERE, "IOException should not have been thrown.", e);
		}
	}
}