JsonStringWriter.java

package org.caudexorigo.json;

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

class JsonStringWriter extends Writer
{
	private StringBuilder buf;

	/**
	 * Create a new string writer using the default initial string-buffer size.
	 */
	protected JsonStringWriter()
	{
		buf = new StringBuilder();
		lock = buf;
	}

	/**
	 * Create a new string writer using the specified initial string-buffer size.
	 * 
	 * @param initialSize
	 *            The number of <tt>char</tt> values that will fit into this buffer before it is automatically expanded
	 * 
	 * @throws IllegalArgumentException
	 *             If <tt>initialSize</tt> is negative
	 */
	protected JsonStringWriter(int initialSize)
	{
		if (initialSize < 0)
		{
			throw new IllegalArgumentException("Negative buffer size");
		}
		buf = new StringBuilder(initialSize);
		lock = buf;
	}

	/**
	 * Write a single character.
	 */
	public void write(int c)
	{
		buf.append((char) c);
	}

	/**
	 * 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
	 */
	public void write(char cbuf[], int off, int len)
	{
		if ((off < 0) || (off > cbuf.length) || (len < 0) || ((off + len) > cbuf.length) || ((off + len) < 0))
		{
			throw new IndexOutOfBoundsException();
		}
		else if (len == 0)
		{
			return;
		}
		buf.append(cbuf, off, len);
	}

	/**
	 * Write a string.
	 */
	public void write(String str)
	{
		buf.append(str);
	}

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

	/**
	 * Appends the specified character sequence to this writer.
	 * 
	 * <p>
	 * An invocation of this method of the form <tt>out.append(csq)</tt> behaves in exactly the same way as the invocation
	 * 
	 * <pre>
	 * out.write(csq.toString())
	 * </pre>
	 * 
	 * <p>
	 * Depending on the specification of <tt>toString</tt> for the character sequence <tt>csq</tt>, the entire sequence may not be appended. For instance, invoking the <tt>toString</tt> method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.
	 * 
	 * @param csq
	 *            The character sequence to append. If <tt>csq</tt> is <tt>null</tt>, then the four characters <tt>"null"</tt> are appended to this writer.
	 * 
	 * @return This writer
	 * 
	 * @since 1.5
	 */
	public JsonStringWriter append(CharSequence csq)
	{
		if (csq == null)
			write("null");
		else
			write(csq.toString());
		return this;
	}

	/**
	 * Appends a subsequence of the specified character sequence to this writer.
	 * 
	 * <p>
	 * An invocation of this method of the form <tt>out.append(csq, start,
	 * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in exactly the same way as the invocation
	 * 
	 * <pre>
	 * out.write(csq.subSequence(start, end).toString())
	 * </pre>
	 * 
	 * @param csq
	 *            The character sequence from which a subsequence will be appended. If <tt>csq</tt> is <tt>null</tt>, then characters will be appended as if <tt>csq</tt> contained the four characters <tt>"null"</tt>.
	 * 
	 * @param start
	 *            The index of the first character in the subsequence
	 * 
	 * @param end
	 *            The index of the character following the last character in the subsequence
	 * 
	 * @return This writer
	 * 
	 * @throws IndexOutOfBoundsException
	 *             If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt> is greater than <tt>end</tt>, or <tt>end</tt> is greater than <tt>csq.length()</tt>
	 * 
	 * @since 1.5
	 */
	public JsonStringWriter append(CharSequence csq, int start, int end)
	{
		CharSequence cs = (csq == null ? "null" : csq);
		write(cs.subSequence(start, end).toString());
		return this;
	}

	/**
	 * Appends the specified character to this writer.
	 * 
	 * <p>
	 * An invocation of this method of the form <tt>out.append(c)</tt> behaves in exactly the same way as the invocation
	 * 
	 * <pre>
	 * out.write(c)
	 * </pre>
	 * 
	 * @param c
	 *            The 16-bit character to append
	 * 
	 * @return This writer
	 * 
	 * @since 1.5
	 */
	public JsonStringWriter append(char c)
	{
		write(c);
		return this;
	}

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

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

	/**
	 * Flush the stream.
	 */
	public void flush()
	{
	}

	/**
	 * Closing a <tt>StringWriter</tt> has no effect. The methods in this class can be called after the stream has been closed without generating an <tt>IOException</tt>.
	 */
	public void close() throws IOException
	{
	}

}