bodycontentimpl.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * 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.jasper.runtime;

import java.io.CharArrayReader;
import java.io.IOException;
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
 * @author Jan Luehe
 */
public class BodyContentImpl extends BodyContent {
    
    private static final String LINE_SEPARATOR = 
        System.getProperty("line.separator");
    private static final boolean LIMIT_BUFFER = 
        Boolean.valueOf(System.getProperty("org.apache.jasper.runtime.BodyContentImpl.LIMIT_BUFFER", "false")).booleanValue();
    
    private char[] cb;
    private int nextChar;
    private boolean closed;
    
    // Enclosed writer to which any output is written
    private Writer writer;
    
    // See comment in setWriter()
    private int bufferSizeSave;
    
    /**
     * Constructor.
     */
    public BodyContentImpl(JspWriter enclosingWriter) {
        super(enclosingWriter);
        bufferSize = Constants.DEFAULT_TAG_BUFFER_SIZE;
        cb = new char[bufferSize];
        nextChar = 0;
        closed = false;
    }
    
    /**
     * Write a single character.
     */
    public void write(int c) throws IOException {
        if (writer != null) {
            writer.write(c);
        } else {
            ensureOpen();
            if (nextChar >= bufferSize) {
                reAllocBuff (1);
            }
            cb[nextChar++] = (char) c;
        }
    }
    
    /**
     * Write a portion of an array of characters.
     *
     * <p> 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
     * <code>DiscardableBufferedWriter</code>s 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 {
        if (writer != null) {
            writer.write(cbuf, off, len);
        } else {
            ensureOpen();
            
            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 {
        if (writer != null) {
            writer.write(buf);
        } else {
            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 {
        if (writer != null) {
            writer.write(s, off, len);
        } else {
            ensureOpen();
            if (len >= bufferSize - nextChar)
                reAllocBuff(len);
            
            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 {
        if (writer != null) {
            writer.write(s);
        } else {
            write(s, 0, s.length());
        }
    }
    
    /**
     * Write a line separator.  The line separator string is defined by the
     * system property <tt>line.separator</tt>, and is not necessarily a single
     * newline ('\n') character.
     *
     * @throws IOException If an I/O error occurs
     */
    public void newLine() throws IOException {
        if (writer != null) {
            writer.write(LINE_SEPARATOR);
        } else {
            write(LINE_SEPARATOR);
        }
    }
    
    /**
     * Print a boolean value.  The string produced by <code>{@link
     * java.lang.String#valueOf(boolean)}</code> is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the <code>{@link
     * #write(int)}</code> method.
     *
     * @param b The <code>boolean</code> to be printed
     * @throws IOException
     */
    public void print(boolean b) throws IOException {
        if (writer != null) {
            writer.write(b ? "true" : "false");
        } else {
            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 <code>{@link
     * #write(int)}</code> method.
     *
     * @param c The <code>char</code> to be printed
     * @throws IOException
     */
    public void print(char c) throws IOException {
        if (writer != null) {
            writer.write(String.valueOf(c));
        } else {
            write(String.valueOf(c));
        }
    }
    
    /**
     * Print an integer.  The string produced by <code>{@link
     * java.lang.String#valueOf(int)}</code> is translated into bytes according
     * to the platform's default character encoding, and these bytes are
     * written in exactly the manner of the <code>{@link #write(int)}</code>
     * method.
     *
     * @param i The <code>int</code> to be printed
     * @throws IOException
     */
    public void print(int i) throws IOException {
        if (writer != null) {
            writer.write(String.valueOf(i));
        } else {
            write(String.valueOf(i));
        }
    }
    
    /**
     * Print a long integer.  The string produced by <code>{@link
     * java.lang.String#valueOf(long)}</code> is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the
     * <code>{@link #write(int)}</code> method.
     *
     * @param l The <code>long</code> to be printed
     * @throws IOException
     */
    public void print(long l) throws IOException {
        if (writer != null) {
            writer.write(String.valueOf(l));
        } else {
            write(String.valueOf(l));
        }
    }
    
    /**
     * Print a floating-point number.  The string produced by <code>{@link
     * java.lang.String#valueOf(float)}</code> is translated into bytes
     * according to the platform's default character encoding, and these bytes
     * are written in exactly the manner of the
     * <code>{@link #write(int)}</code> method.
     *
     * @param f The <code>float</code> to be printed
     * @throws IOException
     */
    public void print(float f) throws IOException {
        if (writer != null) {
            writer.write(String.valueOf(f));
        } else {
            write(String.valueOf(f));
        }
    }
    
    /**
     * Print a double-precision floating-point number.  The string produced by
     * <code>{@link java.lang.String#valueOf(double)}</code> is translated into
     * bytes according to the platform's default character encoding, and these
     * bytes are written in exactly the manner of the <code>{@link
     * #write(int)}</code> method.
     *
     * @param d The <code>double</code> to be printed
     * @throws IOException
     */
    public void print(double d) throws IOException {
        if (writer != null) {
            writer.write(String.valueOf(d));
        } else {
            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
     * <code>{@link #write(int)}</code> method.
     *
     * @param s The array of chars to be printed
     *
     * @throws NullPointerException If <code>s</code> is <code>null</code>
     * @throws IOException
     */
    public void print(char[] s) throws IOException {
        if (writer != null) {
            writer.write(s);
        } else {
            write(s);
        }
    }
    
    /**
     * Print a string.  If the argument is <code>null</code> then the string