Update #0 - First Release

sources/main/java/com/google/common/io/ByteSink.java

@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2012 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 static com.google.common.base.Preconditions.checkNotNull;
+
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.charset.Charset;
+
+/**
+ * A destination to which bytes can be written, such as a file. Unlike an
+ * {@link OutputStream}, a {@code ByteSink} is not an open, stateful stream that
+ * can be written to and closed. Instead, it is an immutable <i>supplier</i> of
+ * {@code OutputStream} instances.
+ *
+ * <p>
+ * {@code ByteSink} provides two kinds of methods:
+ * <ul>
+ * <li><b>Methods that return a stream:</b> These methods should return a
+ * <i>new</i>, independent instance each time they are called. The caller is
+ * responsible for ensuring that the returned stream is closed.
+ * <li><b>Convenience methods:</b> These are implementations of common
+ * operations that are typically implemented by opening a stream using one of
+ * the methods in the first category, doing something and finally closing the
+ * stream or channel that was opened.
+ * </ul>
+ *
+ * @since 14.0
+ * @author Colin Decker
+ */
+public abstract class ByteSink implements OutputSupplier<OutputStream> {
+
+	/**
+	 * Constructor for use by subclasses.
+	 */
+	protected ByteSink() {
+	}
+
+	/**
+	 * Returns a {@link CharSink} view of this {@code ByteSink} that writes
+	 * characters to this sink as bytes encoded with the given {@link Charset
+	 * charset}.
+	 */
+	public CharSink asCharSink(Charset charset) {
+		return new AsCharSink(charset);
+	}
+
+	/**
+	 * Opens a new {@link OutputStream} for writing to this sink. This method should
+	 * return a new, independent stream each time it is called.
+	 *
+	 * <p>
+	 * The caller is responsible for ensuring that the returned stream is closed.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of opening the
+	 *                     stream
+	 */
+	public abstract OutputStream openStream() throws IOException;
+
+	/**
+	 * This method is a temporary method provided for easing migration from
+	 * suppliers to sources and sinks.
+	 *
+	 * @since 15.0
+	 * @deprecated This method is only provided for temporary compatibility with the
+	 *             {@link OutputSupplier} interface and should not be called
+	 *             directly. Use {@link #openStream} instead. This method is
+	 *             scheduled for removal in Guava 18.0.
+	 */
+	@Override
+	@Deprecated
+	public final OutputStream getOutput() throws IOException {
+		return openStream();
+	}
+
+	/**
+	 * Opens a new buffered {@link OutputStream} for writing to this sink. The
+	 * returned stream is not required to be a {@link BufferedOutputStream} in order
+	 * to allow implementations to simply delegate to {@link #openStream()} when the
+	 * stream returned by that method does not benefit from additional buffering
+	 * (for example, a {@code ByteArrayOutputStream}). This method should return a
+	 * new, independent stream each time it is called.
+	 *
+	 * <p>
+	 * The caller is responsible for ensuring that the returned stream is closed.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of opening the
+	 *                     stream
+	 * @since 15.0 (in 14.0 with return type {@link BufferedOutputStream})
+	 */
+	public OutputStream openBufferedStream() throws IOException {
+		OutputStream out = openStream();
+		return (out instanceof BufferedOutputStream) ? (BufferedOutputStream) out : new BufferedOutputStream(out);
+	}
+
+	/**
+	 * Writes all the given bytes to this sink.
+	 *
+	 * @throws IOException if an I/O occurs in the process of writing to this sink
+	 */
+	public void write(byte[] bytes) throws IOException {
+		checkNotNull(bytes);
+
+		Closer closer = Closer.create();
+		try {
+			OutputStream out = closer.register(openStream());
+			out.write(bytes);
+			out.flush(); // https://code.google.com/p/guava-libraries/issues/detail?id=1330
+		} catch (Throwable e) {
+			throw closer.rethrow(e);
+		} finally {
+			closer.close();
+		}
+	}
+
+	/**
+	 * Writes all the bytes from the given {@code InputStream} to this sink. Does
+	 * not close {@code input}.
+	 *
+	 * @throws IOException if an I/O occurs in the process of reading from
+	 *                     {@code input} or writing to this sink
+	 */
+	public long writeFrom(InputStream input) throws IOException {
+		checkNotNull(input);
+
+		Closer closer = Closer.create();
+		try {
+			OutputStream out = closer.register(openStream());
+			long written = ByteStreams.copy(input, out);
+			out.flush(); // https://code.google.com/p/guava-libraries/issues/detail?id=1330
+			return written;
+		} catch (Throwable e) {
+			throw closer.rethrow(e);
+		} finally {
+			closer.close();
+		}
+	}
+
+	/**
+	 * A char sink that encodes written characters with a charset and writes
+	 * resulting bytes to this byte sink.
+	 */
+	private final class AsCharSink extends CharSink {
+
+		private final Charset charset;
+
+		private AsCharSink(Charset charset) {
+			this.charset = checkNotNull(charset);
+		}
+
+		@Override
+		public Writer openStream() throws IOException {
+			return new OutputStreamWriter(ByteSink.this.openStream(), charset);
+		}
+
+		@Override
+		public String toString() {
+			return ByteSink.this.toString() + ".asCharSink(" + charset + ")";
+		}
+	}
+}