/* | |
* 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.logging.log4j.core.util; | |
import java.io.Serializable; | |
import java.io.Writer; | |
/** | |
* {@link Writer} implementation that outputs to a {@link StringBuilder}. | |
* <p> | |
* <strong>NOTE:</strong> This implementation, as an alternative to | |
* <code>java.io.StringWriter</code>, provides an <i>un-synchronized</i> | |
* (i.e. for use in a single thread) implementation for better performance. | |
* For safe usage with multiple {@link Thread}s then | |
* <code>java.io.StringWriter</code> should be used. | |
* | |
* <h3>History</h3> | |
* <ol> | |
* <li>Copied from Apache Commons IO revision 1681000.</li> | |
* <li>Pick up Javadoc updates from revision 1722253.</li> | |
* <ol> | |
*/ | |
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}. | |
* | |
* <p>If {@code builder} is null a new instance with default capacity will be created.</p> | |
* | |
* @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(); | |
} | |
} |