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/*
* 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.
*
* @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();
}
}