/*
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed 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.jasper.runtime;

import java.io.CharArrayReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;

import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyContent;

import org.apache.jasper.Constants;

/**
 * Write text to a character-output stream, buffering characters so as
 * to provide for the efficient writing of single characters, arrays,
 * and strings. 
 *
 * Provide support for discarding for the output that has been buffered. 
 *
 * @author Rajiv Mordani
 */
public class BodyContentImpl extends BodyContent {

    private char[] cb;
    protected int bufferSize = Constants.DEFAULT_BUFFER_SIZE;
    private int nextChar;
    static String lineSeparator = System.getProperty("line.separator");


    public BodyContentImpl (JspWriter writer) {
        super(writer);
	cb = new char[bufferSize];
	nextChar = 0;
	 }

    /**
     * Write a single character.
     *
     */
    public void write(int c) throws IOException {
        synchronized (lock) {
            if (nextChar >= bufferSize) {
	        reAllocBuff (0);
	    }
            cb[nextChar++] = (char) c;
        }
    }

    /** Make space for len chars. If len is small, allocate
	a reserve space too.
     */
    private void reAllocBuff (int len) {
        //Need to re-allocate the buffer since it is to be
 	//unbounded according to the updated spec..

        char[] tmp = null;

        if(len <= bufferSize){ 
            bufferSize *= 2; 
        }else{ 
            bufferSize += len; 
        } 
        tmp = new char[bufferSize]; 
	System.arraycopy(cb, 0, tmp, 0, cb.length);
	cb = tmp;
	tmp = null;
    }

    /**
     * Write a portion of an array of characters.
     *
     * 
 Ordinarily this method stores characters from the given array into
     * this stream's buffer, flushing the buffer to the underlying stream as
     * needed.  If the requested length is at least as large as the buffer,
     * however, then this method will flush the buffer and write the characters
     * directly to the underlying stream.  Thus redundant
     * DiscardableBufferedWriters will not copy data unnecessarily.
     *
     * @param  cbuf  A character array
     * @param  off   Offset from which to start reading characters
     * @param  len   Number of characters to write
     *
     */
    public void write(char cbuf[], int off, int len) 
        throws IOException 
    {
        synchronized (lock) {

            if ((off < 0) || (off > cbuf.length) || (len < 0) ||
                ((off + len) > cbuf.length) || ((off + len) < 0)) {
                throw new IndexOutOfBoundsException();
            } else if (len == 0) {
                return;
            } 

            if (len >= bufferSize - nextChar)
		   reAllocBuff (len);

            System.arraycopy(cbuf, off, cb, nextChar, len);
	    nextChar+=len;
        }
    }

    /**
     * Write an array of characters.  This method cannot be inherited from the
     * Writer class because it must suppress I/O exceptions.
     */
    public void write(char buf[]) throws IOException {
	write(buf, 0, buf.length);
    }

    /**
     * Write a portion of a String.
     *
     * @param  s     String to be written
     * @param  off   Offset from which to start reading characters
     * @param  len   Number of characters to be written
     *
     */
    public void write(String s, int off, int len) throws IOException {
        synchronized (lock) {
	    if (len >= bufferSize - nextChar)
	        reAllocBuff(len);

	    //System.out.println("XXX " + off + " " + (off+len) + " " +
	    // nextChar + " " + bufferSize + " "+  cb.length);
            s.getChars(off, off + len, cb, nextChar);
	    nextChar += len;
        }
    }

    /**
     * Write a string.  This method cannot be inherited from the Writer class
     * because it must suppress I/O exceptions.
     */
    public void write(String s) throws IOException {
	write(s, 0, s.length());
    }


    /**
     * Write a line separator.  The line separator string is defined by the
     * system property line.separator, and is not necessarily a single
     * newline ('\n') character.
     *
     * @exception  IOException  If an I/O error occurs
     */

    public void newLine() throws IOException {
	synchronized (lock) {
	    write(lineSeparator);
	}
    }

    /**
     * Print a boolean value.  The string produced by {@link
     * java.lang.String#valueOf(boolean)} is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the {@link
     * #write(int)} method.
     *
     * @param      b   The boolean to be printed
     * @throws	   java.io.IOException
     */

    public void print(boolean b) throws IOException {
	write(b ? "true" : "false");
    }

    /**
     * Print a character.  The character is translated into one or more bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the {@link
     * #write(int)} method.
     *
     * @param      c   The char to be printed
     * @throws	   java.io.IOException
     */

    public void print(char c) throws IOException {
	write(String.valueOf(c));
    }

    /**
     * Print an integer.  The string produced by {@link
     * java.lang.String#valueOf(int)} is translated into bytes according
     * to the platform's default character encoding, and these bytes are
     * written in exactly the manner of the {@link #write(int)}
     * method.
     *
     * @param      i   The int to be printed
     * @see        java.lang.Integer#toString(int)
     * @throws	   java.io.IOException
     */

    public void print(int i) throws IOException {
	write(String.valueOf(i));
    }

    /**
     * Print a long integer.  The string produced by {@link
     * java.lang.String#valueOf(long)} is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the {@link #write(int)}
     * method.
     *
     * @param      l   The long to be printed
     * @see        java.lang.Long#toString(long)
     * @throws	   java.io.IOException
     */

    public void print(long l) throws IOException {
	write(String.valueOf(l));
    }

    /**
     * Print a floating-point number.  The string produced by {@link
     * java.lang.String#valueOf(float)} is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the {@link #write(int)}
     * method.
     *
     * @param      f   The float to be printed
     * @see        java.lang.Float#toString(float)
     * @throws	   java.io.IOException
     */

    public void print(float f) throws IOException {
	write(String.valueOf(f));
    }

    /**
     * Print a double-precision floating-point number.  The string produced by
     * {@link java.lang.String#valueOf(double)} is translated into
     * bytes according to the platform's default character encoding, and these
     * bytes are written in exactly the manner of the {@link
     * #write(int)} method.
     *
     * @param      d   The double to be printed
     * @see        java.lang.Double#toString(double)
     * @throws	   java.io.IOException
     */

    public void print(double d) throws IOException {
	write(String.valueOf(d));
    }

    /**
     * Print an array of characters.  The characters are converted into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the {@link #write(int)}
     * method.
     *
     * @param      s   The array of chars to be printed
     *
     * @throws  NullPointerException  If s is null
     * @throws	   java.io.IOException
     */

    public void print(char s[]) throws IOException {
	write(s);
    }

    /**
     * Print a string.  If the argument is null then the string
     * "null" is printed.  Otherwise, the string's characters are
     * converted into bytes according to the platform's default character
     * encoding, and these bytes are written in exactly the manner of the
     * {@link #write(int)} method.
     *
     * @param      s   The String to be printed
     * @throws	   java.io.IOException
     */

    public void print(String s) throws IOException {
	if (s == null) {
	    s = "null";
	}
	write(s);
    }

    /**
     * Print an object.  The string produced by the {@link
     * java.lang.String#valueOf(Object)} method is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the {@link #write(int)}
     * method.
     *
     * @param      obj   The Object to be printed
     * @see        java.lang.Object#toString()
     * @throws	   java.io.IOException
     */

    public void print(Object obj) throws IOException {
	write(String.valueOf(obj));
    }

    /**
     * Terminate the current line by writing the line separator string.  The
     * line separator string is defined by the system property
     * line.separator, and is not necessarily a single newline
     * character ('\n').
     * @throws	   java.io.IOException
     */

    public void println() throws IOException {
	newLine();
    }

    /**
     * Print a boolean value and then terminate the line.  This method behaves
     * as though it invokes {@link #print(boolean)} and then
     * {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(boolean x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print a character and then terminate the line.  This method behaves as
     * though it invokes {@link #print(char)} and then {@link
     * #println()}.
     * @throws	   java.io.IOException
     */

    public void println(char x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print an integer and then terminate the line.  This method behaves as
     * though it invokes {@link #print(int)} and then {@link
     * #println()}.
     * @throws	   java.io.IOException
     */

    public void println(int x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print a long integer and then terminate the line.  This method behaves
     * as though it invokes {@link #print(long)} and then
     * {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(long x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print a floating-point number and then terminate the line.  This method
     * behaves as though it invokes {@link #print(float)} and then
     * {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(float x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print a double-precision floating-point number and then terminate the
     * line.  This method behaves as though it invokes {@link
     * #print(double)} and then {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(double x) throws IOException{
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print an array of characters and then terminate the line.  This method
     * behaves as though it invokes {@link #print(char[])} and then
     * {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(char x[]) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print a String and then terminate the line.  This method behaves as
     * though it invokes {@link #print(String)} and then
     * {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(String x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Print an Object and then terminate the line.  This method behaves as
     * though it invokes {@link #print(Object)} and then
     * {@link #println()}.
     * @throws	   java.io.IOException
     */

    public void println(Object x) throws IOException {
	synchronized (lock) {
	    print(x);
	    println();
	}
    }

    /**
     * Clear the contents of the buffer. If the buffer has been already
     * been flushed then the clear operation shall throw an IOException
     * to signal the fact that some data has already been irrevocably 
     * written to the client response stream.
     *
     * @throws IOException		If an I/O error occurs
     */

    public void clear() throws IOException {
        synchronized (lock) {
	    nextChar = 0;
	}
    }

    /**
     * Clears the current contents of the buffer. Unlike clear(), this
     * mehtod will not throw an IOException if the buffer has already been
     * flushed. It merely clears the current content of the buffer and
     * returns.
     *
     * @throws IOException		If an I/O error occurs
     */

    public void clearBuffer() throws IOException {
        this.clear();
    }

    /**
     * Close the stream, flushing it first.  Once a stream has been closed,
     * further write() or flush() invocations will cause an IOException to be
     * thrown.  Closing a previously-closed stream, however, has no effect.
     *
     * @exception  IOException  If an I/O error occurs
     */

    public void close() throws IOException {
        synchronized (lock) {
	    cb = null;	
	}
    }

    /**
     * @return the number of bytes unused in the buffer
     */

    public int getRemaining() {
        return bufferSize - nextChar;
    }

    /**
     * Return the value of this BodyJspWriter as a Reader.
     * Note: this is after evaluation!!  There are no scriptlets,
     * etc in this stream.
     *
     * @returns the value of this BodyJspWriter as a Reader
     */
    public Reader getReader() {
        return new CharArrayReader (cb, 0, nextChar);
    }

    /**
     * Return the value of the BodyJspWriter as a String.
     * Note: this is after evaluation!!  There are no scriptlets,
     * etc in this stream.
     *
     * @returns the value of the BodyJspWriter as a String
     */
    public String getString() {
        return new String(cb, 0, nextChar);
    }
	
    /**
     * Write the contents of this BodyJspWriter into a Writer.
     * Subclasses are likely to do interesting things with the
     * implementation so some things are extra efficient.
     *
     * @param out The writer into which to place the contents of
     * this body evaluation
     */
    public void writeOut(Writer out) throws IOException {
        out.write(cb, 0, nextChar);
	// Flush not called as the writer passed could be a BodyContent and
	// it doesn't allow to flush.
    }


    public static void main (String[] args) throws Exception {
	char[] buff = {'f','o','o','b','a','r','b','a','z','y'};
   	BodyContentImpl bodyContent = new BodyContentImpl(new JspWriterImpl(
							null, 100, false));
	bodyContent.println (buff);
	System.out.println (bodyContent.getString ());
	bodyContent.writeOut (new PrintWriter (System.out));
    }
}