org.apache.jasper.runtime.BodyContentImpl Maven / Gradle / Ivy
/*
* 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;
/**
* 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.
*/
@Override
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.
*
* 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
*/
@Override
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.
*/
@Override
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
*/
@Override
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.
*/
@Override
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 line.separator, and is not necessarily a single
* newline ('\n') character.
*
* @throws IOException If an I/O error occurs
*/
@Override
public void newLine() throws IOException {
if (writer != null) {
writer.write(LINE_SEPARATOR);
} else {
write(LINE_SEPARATOR);
}
}
/**
* 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 IOException
*/
@Override
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 {@link
* #write(int)} method.
*
* @param c The char to be printed
* @throws IOException
*/
@Override
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 {@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
* @throws IOException
*/
@Override
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 {@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
* @throws IOException
*/
@Override
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 {@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
* @throws IOException
*/
@Override
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
* {@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
* @throws IOException
*/
@Override
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
* {@link #write(int)} method.
*
* @param s The array of chars to be printed
*
* @throws NullPointerException If s is null
* @throws IOException
*/
@Override
public void print(char[] s) throws IOException {
if (writer != null) {
writer.write(s);
} else {
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 IOException
*/
@Override
public void print(String s) throws IOException {
if (s == null) s = "null";
if (writer != null) {
writer.write(s);
} else {
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
* @throws IOException
*/
@Override
public void print(Object obj) throws IOException {
if (writer != null) {
writer.write(String.valueOf(obj));
} else {
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 IOException
*/
@Override
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 IOException
*/
@Override
public void println(boolean x) throws IOException {
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 IOException
*/
@Override
public void println(char x) throws IOException {
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 IOException
*/
@Override
public void println(int x) throws IOException {
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 IOException
*/
@Override
public void println(long x) throws IOException {
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 IOException
*/
@Override
public void println(float x) throws IOException {
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 IOException
*/
@Override
public void println(double x) throws IOException{
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 IOException
*/
@Override
public void println(char x[]) throws IOException {
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 IOException
*/
@Override
public void println(String x) throws IOException {
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 IOException
*/
@Override
public void println(Object x) throws IOException {
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
*/
@Override
public void clear() throws IOException {
if (writer != null) {
throw new IOException();
} else {
nextChar = 0;
if (LIMIT_BUFFER && (cb.length > Constants.DEFAULT_TAG_BUFFER_SIZE)) {
bufferSize = Constants.DEFAULT_TAG_BUFFER_SIZE;
cb = new char[bufferSize];
}
}
}
/**
* Clears the current contents of the buffer. Unlike clear(), this
* method 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
*/
@Override
public void clearBuffer() throws IOException {
if (writer == null) {
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.
*
* @throws IOException If an I/O error occurs
*/
@Override
public void close() throws IOException {
if (writer != null) {
writer.close();
} else {
closed = true;
}
}
/**
* This method returns the size of the buffer used by the JspWriter.
*
* @return the size of the buffer in bytes, or 0 is unbuffered.
*/
@Override
public int getBufferSize() {
// According to the spec, the JspWriter returned by
// JspContext.pushBody(java.io.Writer writer) must behave as
// though it were unbuffered. This means that its getBufferSize()
// must always return 0.
return (writer == null) ? bufferSize : 0;
}
/**
* @return the number of bytes unused in the buffer
*/
@Override
public int getRemaining() {
return (writer == null) ? bufferSize-nextChar : 0;
}
/**
* Return the value of this BodyJspWriter as a Reader.
* Note: this is after evaluation!! There are no scriptlets,
* etc in this stream.
*
* @return the value of this BodyJspWriter as a Reader
*/
@Override
public Reader getReader() {
return (writer == null) ? new CharArrayReader (cb, 0, nextChar) : null;
}
/**
* Return the value of the BodyJspWriter as a String.
* Note: this is after evaluation!! There are no scriptlets,
* etc in this stream.
*
* @return the value of the BodyJspWriter as a String
*/
@Override
public String getString() {
return (writer == null) ? new String(cb, 0, nextChar) : null;
}
/**
* 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
*/
@Override
public void writeOut(Writer out) throws IOException {
if (writer == null) {
out.write(cb, 0, nextChar);
// Flush not called as the writer passed could be a BodyContent and
// it doesn't allow to flush.
}
}
/**
* Sets the writer to which all output is written.
*/
void setWriter(Writer writer) {
this.writer = writer;
closed = false;
if (writer == null) {
clearBody();
}
}
/**
* This method shall "reset" the internal state of a BodyContentImpl,
* releasing all internal references, and preparing it for potential
* reuse by a later invocation of {@link PageContextImpl#pushBody(Writer)}.
*
*
Note, that BodyContentImpl instances are usually owned by a
* PageContextImpl instance, and PageContextImpl instances are recycled
* and reused.
*
* @see PageContextImpl#release()
*/
protected void recycle() {
this.writer = null;
try {
this.clear();
} catch (IOException ex) {
// ignore
}
}
private void ensureOpen() throws IOException {
if (closed) throw new IOException("Stream closed");
}
/**
* Reallocates buffer since the spec requires it to be unbounded.
*/
private void reAllocBuff(int len) {
if (bufferSize + len <= cb.length) {
bufferSize = cb.length;
return;
}
if (len < cb.length) {
len = cb.length;
}
bufferSize = cb.length + len;
char[] tmp = new char[bufferSize];
System.arraycopy(cb, 0, tmp, 0, cb.length);
cb = tmp;
tmp = null;
}
}