org.apache.jasper.runtime.JspWriterImpl 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 static org.apache.jasper.JasperMessages.MESSAGES;
import java.io.IOException;
import java.io.Writer;
import javax.servlet.ServletResponse;
import javax.servlet.jsp.JspWriter;
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.
*
* This needs revisiting when the buffering problems in the JSP spec
* are fixed -akv
*
* @author Anil K. Vijendran
*/
public class JspWriterImpl extends JspWriter {
private Writer out;
private ServletResponse response;
private char cb[];
private int nextChar;
private boolean flushed = false;
private boolean closed = false;
public JspWriterImpl() {
super( Constants.DEFAULT_BUFFER_SIZE, true );
}
/**
* Create a new buffered character-output stream that uses an output
* buffer of the given size.
*
* @param response A Servlet Response
* @param sz Output-buffer size, a positive integer
* @param autoFlush true to automatically flush on buffer
* full, false to throw an overflow exception in that case
* @exception IllegalArgumentException If sz is <= 0
*/
public JspWriterImpl(ServletResponse response, int sz,
boolean autoFlush) {
super(sz, autoFlush);
if (sz < 0)
throw MESSAGES.invalidNegativeBufferSize();
this.response = response;
cb = sz == 0 ? null : new char[sz];
nextChar = 0;
}
void init( ServletResponse response, int sz, boolean autoFlush ) {
this.response= response;
if( sz > 0 && ( cb == null || sz > cb.length ) )
cb=new char[sz];
nextChar = 0;
this.autoFlush=autoFlush;
this.bufferSize=sz;
}
/**
* Package-level access
*/
void recycle() {
flushed = false;
closed = false;
out = null;
nextChar = 0;
response = null;
}
/**
* Flush the output buffer to the underlying character stream, without
* flushing the stream itself. This method is non-private only so that it
* may be invoked by PrintStream.
* @throws IOException Error writing buffered data
*/
protected final void flushBuffer() throws IOException {
if (bufferSize == 0)
return;
flushed = true;
ensureOpen();
if (nextChar == 0)
return;
initOut();
out.write(cb, 0, nextChar);
nextChar = 0;
}
private void initOut() throws IOException {
if (out == null) {
out = response.getWriter();
}
}
/**
* Discard the output buffer.
*/
@Override
public final void clear() throws IOException {
if ((bufferSize == 0) && (out != null))
// clear() is illegal after any unbuffered output (JSP.5.5)
throw MESSAGES.cannotClearWithNoBuffer();
if (flushed)
throw MESSAGES.cannotClearAfterFlush();
ensureOpen();
nextChar = 0;
}
@Override
public void clearBuffer() throws IOException {
if (bufferSize == 0)
throw MESSAGES.cannotClearWithNoBuffer();
ensureOpen();
nextChar = 0;
}
private final void bufferOverflow() throws IOException {
throw MESSAGES.bufferOverflow();
}
/**
* Flush the stream.
*
*/
@Override
public void flush() throws IOException {
flushBuffer();
if (out != null) {
out.flush();
}
}
/**
* Close the stream.
*
*/
@Override
public void close() throws IOException {
if (response == null || closed)
// multiple calls to close is OK
return;
flush();
if (out != null)
out.close();
out = null;
closed = true;
}
/**
* @return the number of bytes unused in the buffer
*/
@Override
public int getRemaining() {
return bufferSize - nextChar;
}
/** check to make sure that the stream has not been closed */
private void ensureOpen() throws IOException {
if (response == null || closed)
throw new IOException(MESSAGES.streamClosed());
}
/**
* Write a single character.
*/
@Override
public void write(int c) throws IOException {
ensureOpen();
if (bufferSize == 0) {
initOut();
out.write(c);
}
else {
if (nextChar >= bufferSize)
if (autoFlush)
flushBuffer();
else
bufferOverflow();
cb[nextChar++] = (char) c;
}
}
/**
* Our own little min method, to avoid loading java.lang.Math if we've run
* out of file descriptors and we're trying to print a stack trace.
*/
private static int min(int a, int b) {
if (a < b) return a;
return b;
}
/**
* 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
{
ensureOpen();
if (bufferSize == 0) {
initOut();
out.write(cbuf, off, len);
return;
}
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) {
/* If the request length exceeds the size of the output buffer,
flush the buffer and then write the data directly. In this
way buffered streams will cascade harmlessly. */
if (autoFlush)
flushBuffer();
else
bufferOverflow();
initOut();
out.write(cbuf, off, len);
return;
}
int b = off, t = off + len;
while (b < t) {
int d = min(bufferSize - nextChar, t - b);
System.arraycopy(cbuf, b, cb, nextChar, d);
b += d;
nextChar += d;
if (nextChar >= bufferSize)
if (autoFlush)
flushBuffer();
else
bufferOverflow();
}
}
/**
* 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 {
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 {
ensureOpen();
if (bufferSize == 0) {
initOut();
out.write(s, off, len);
return;
}
int b = off, t = off + len;
while (b < t) {
int d = min(bufferSize - nextChar, t - b);
s.getChars(b, b + d, cb, nextChar);
b += d;
nextChar += d;
if (nextChar >= bufferSize)
if (autoFlush)
flushBuffer();
else
bufferOverflow();
}
}
/**
* 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
*/
@Override
public void newLine() throws IOException {
write(System.lineSeparator());
}
/* Methods that do not terminate lines */
/**
* 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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
public void print(Object obj) throws IOException {
write(String.valueOf(obj));
}
/* Methods that do terminate lines */
/**
* 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').
*
* Need to change this from PrintWriter because the default
* println() writes to the sink directly instead of through the
* write method...
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@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()}.
*/
@Override
public void println(Object x) throws IOException {
print(x);
println();
}
}