/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.io.output;

import java.io.Serializable;
import java.io.Writer;

/**
 * {@link Writer} implementation that outputs to a {@link StringBuilder}.
 * 

* NOTE: This implementation, as an alternative to * java.io.StringWriter, provides an un-synchronized * (i.e. for use in a single thread) implementation for better performance. * For safe usage with multiple {@link Thread}s then * java.io.StringWriter should be used. * * @version $Id$ * @since 2.0 */ public class StringBuilderWriter extends Writer implements Serializable { private static final long serialVersionUID = -146927496096066153L; private final StringBuilder builder; /** * Constructs a new {@link StringBuilder} instance with default capacity. */ public StringBuilderWriter() { this.builder = new StringBuilder(); } /** * Constructs a new {@link StringBuilder} instance with the specified capacity. * * @param capacity The initial capacity of the underlying {@link StringBuilder} */ public StringBuilderWriter(final int capacity) { this.builder = new StringBuilder(capacity); } /** * Constructs a new instance with the specified {@link StringBuilder}. * *

If {@code builder} is null a new instance with default capacity will be created.

* * @param builder The String builder. May be null. */ public StringBuilderWriter(final StringBuilder builder) { this.builder = builder != null ? builder : new StringBuilder(); } /** * Appends a single character to this Writer. * * @param value The character to append * @return This writer instance */ @Override public Writer append(final char value) { builder.append(value); return this; } /** * Appends a character sequence to this Writer. * * @param value The character to append * @return This writer instance */ @Override public Writer append(final CharSequence value) { builder.append(value); return this; } /** * Appends a portion of a character sequence to the {@link StringBuilder}. * * @param value The character to append * @param start The index of the first character * @param end The index of the last character + 1 * @return This writer instance */ @Override public Writer append(final CharSequence value, final int start, final int end) { builder.append(value, start, end); return this; } /** * Closing this writer has no effect. */ @Override public void close() { // no-op } /** * Flushing this writer has no effect. */ @Override public void flush() { // no-op } /** * Writes a String to the {@link StringBuilder}. * * @param value The value to write */ @Override public void write(final String value) { if (value != null) { builder.append(value); } } /** * Writes a portion of a character array to the {@link StringBuilder}. * * @param value The value to write * @param offset The index of the first character * @param length The number of characters to write */ @Override public void write(final char[] value, final int offset, final int length) { if (value != null) { builder.append(value, offset, length); } } /** * Returns the underlying builder. * * @return The underlying builder */ public StringBuilder getBuilder() { return builder; } /** * Returns {@link StringBuilder#toString()}. * * @return The contents of the String builder. */ @Override public String toString() { return builder.toString(); } }