com.sun.faces.io.FastStringWriter Maven / Gradle / Ivy

/*
 * Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.faces.io;

import java.io.IOException;
import java.io.Writer;

/**
 * 
 * This is based on {@link java.io.StringWriter} but backed by a {@link StringBuilder} instead.
 * 
 * 
 * 
 * This class is not thread safe.
 * 
 */
public class FastStringWriter extends Writer {

    protected StringBuilder builder;

    // ------------------------------------------------------------ Constructors

    /**
     * 
     * Constructs a new FastStringWriter instance using the default capacity of 16.
     * 
     */
    public FastStringWriter() {
        builder = new StringBuilder();
    }

    /**
     * 
     * Constructs a new FastStringWriter instance using the specified initialCapacity.
     * 
     *
     * @param initialCapacity specifies the initial capacity of the buffer
     *
     * @throws IllegalArgumentException if initialCapacity is less than zero
     */
    public FastStringWriter(int initialCapacity) {
        if (initialCapacity < 0) {
            throw new IllegalArgumentException();
        }
        builder = new StringBuilder(initialCapacity);
    }

    // ----------------------------------------------------- Methods from Writer

    /**
     * 
     * Write a portion of an array of characters.
     * 
     *
     * @param cbuf Array of characters
     * @param off Offset from which to start writing characters
     * @param len Number of characters to write
     *
     * @throws IOException
     */
    @Override
    public void write(char cbuf[], int off, int len) throws IOException {
        if (off < 0 || off > cbuf.length || len < 0 || off + len > cbuf.length || off + len < 0) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
            return;
        }
        builder.append(cbuf, off, len);
    }

    /**
     * 
     * This is a no-op.
     * 
     *
     * @throws IOException
     */
    @Override
    public void flush() throws IOException {
    }

    /**
     * 
     * This is a no-op.
     * 
     *
     * @throws IOException
     */
    @Override
    public void close() throws IOException {
    }

    // ---------------------------------------------------------- Public Methods

    /**
     * Write a string.
     *
     * @param str String to be written
     */
    @Override
    public void write(String str) {
        builder.append(str);
    }

    /**
     * Write a portion of a string.
     *
     * @param str A String
     * @param off Offset from which to start writing characters
     * @param len Number of characters to write
     */
    @Override
    public void write(String str, int off, int len) {
        builder.append(str.substring(off, off + len));
    }

    /**
     * Return the StringBuilder itself.
     *
     * @return StringBuilder holding the current buffer value.
     */
    public StringBuilder getBuffer() {
        return builder;
    }

    /** @return the buffer's current value as a string. */
    @Override
    public String toString() {
        return builder.toString();
    }

    public void reset() {
        builder.setLength(0);
    }

}