Update #0 - First Release

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

@@ -0,0 +1,190 @@
+/*
+ * 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.BufferedWriter;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.Writer;
+import java.nio.charset.Charset;
+
+/**
+ * A destination to which characters can be written, such as a text file. Unlike
+ * a {@link Writer}, a {@code CharSink} is not an open, stateful stream that can
+ * be written to and closed. Instead, it is an immutable <i>supplier</i> of
+ * {@code Writer} instances.
+ *
+ * <p>
+ * {@code CharSink} provides two kinds of methods:
+ * <ul>
+ * <li><b>Methods that return a writer:</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 writer is closed.
+ * <li><b>Convenience methods:</b> These are implementations of common
+ * operations that are typically implemented by opening a writer using one of
+ * the methods in the first category, doing something and finally closing the
+ * writer that was opened.
+ * </ul>
+ *
+ * <p>
+ * Any {@link ByteSink} may be viewed as a {@code CharSink} with a specific
+ * {@linkplain Charset character encoding} using
+ * {@link ByteSink#asCharSink(Charset)}. Characters written to the resulting
+ * {@code CharSink} will written to the {@code ByteSink} as encoded bytes.
+ *
+ * @since 14.0
+ * @author Colin Decker
+ */
+public abstract class CharSink implements OutputSupplier<Writer> {
+
+	/**
+	 * Constructor for use by subclasses.
+	 */
+	protected CharSink() {
+	}
+
+	/**
+	 * Opens a new {@link Writer} for writing to this sink. This method should
+	 * return a new, independent writer each time it is called.
+	 *
+	 * <p>
+	 * The caller is responsible for ensuring that the returned writer is closed.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of opening the
+	 *                     writer
+	 */
+	public abstract Writer 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 Writer getOutput() throws IOException {
+		return openStream();
+	}
+
+	/**
+	 * Opens a new buffered {@link Writer} for writing to this sink. The returned
+	 * stream is not required to be a {@link BufferedWriter} in order to allow
+	 * implementations to simply delegate to {@link #openStream()} when the stream
+	 * returned by that method does not benefit from additional buffering. This
+	 * method should return a new, independent writer each time it is called.
+	 *
+	 * <p>
+	 * The caller is responsible for ensuring that the returned writer is closed.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of opening the
+	 *                     writer
+	 * @since 15.0 (in 14.0 with return type {@link BufferedWriter})
+	 */
+	public Writer openBufferedStream() throws IOException {
+		Writer writer = openStream();
+		return (writer instanceof BufferedWriter) ? (BufferedWriter) writer : new BufferedWriter(writer);
+	}
+
+	/**
+	 * Writes the given character sequence to this sink.
+	 *
+	 * @throws IOException if an I/O error in the process of writing to this sink
+	 */
+	public void write(CharSequence charSequence) throws IOException {
+		checkNotNull(charSequence);
+
+		Closer closer = Closer.create();
+		try {
+			Writer out = closer.register(openStream());
+			out.append(charSequence);
+			out.flush(); // https://code.google.com/p/guava-libraries/issues/detail?id=1330
+		} catch (Throwable e) {
+			throw closer.rethrow(e);
+		} finally {
+			closer.close();
+		}
+	}
+
+	/**
+	 * Writes the given lines of text to this sink with each line (including the
+	 * last) terminated with the operating system's default line separator. This
+	 * method is equivalent to
+	 * {@code writeLines(lines, System.getProperty("line.separator"))}.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of writing to this
+	 *                     sink
+	 */
+	public void writeLines(Iterable<? extends CharSequence> lines) throws IOException {
+		writeLines(lines, System.getProperty("line.separator"));
+	}
+
+	/**
+	 * Writes the given lines of text to this sink with each line (including the
+	 * last) terminated with the given line separator.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of writing to this
+	 *                     sink
+	 */
+	public void writeLines(Iterable<? extends CharSequence> lines, String lineSeparator) throws IOException {
+		checkNotNull(lines);
+		checkNotNull(lineSeparator);
+
+		Closer closer = Closer.create();
+		try {
+			Writer out = closer.register(openBufferedStream());
+			for (CharSequence line : lines) {
+				out.append(line).append(lineSeparator);
+			}
+			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 text from the given {@link Readable} (such as a
+	 * {@link Reader}) to this sink. Does not close {@code readable} if it is
+	 * {@code Closeable}.
+	 *
+	 * @throws IOException if an I/O error occurs in the process of reading from
+	 *                     {@code readable} or writing to this sink
+	 */
+	public long writeFrom(Readable readable) throws IOException {
+		checkNotNull(readable);
+
+		Closer closer = Closer.create();
+		try {
+			Writer out = closer.register(openStream());
+			long written = CharStreams.copy(readable, 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();
+		}
+	}
+}