JspWriterImpl.java
/*
* 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.IOException;
import java.io.PrintWriter;
import java.io.Writer;
import javax.servlet.ServletResponse;
import javax.servlet.jsp.JspWriter;
import org.apache.jasper.Constants;
import org.apache.jasper.compiler.Localizer;
/**
* 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 <code>true</code> to automatically flush on buffer
* full, <code>false</code> 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 new IllegalArgumentException(Localizer.getMessage("jsp.error.negativeBufferSize"));
}
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) {
try {
out = response.getWriter();
} catch (IllegalStateException e) {
/*
* At some point in the processing something (most likely the default servlet as the target of a
* <jsp:forward ... /> action) wrote directly to the OutputStream rather than the Writer. Wrap the
* OutputStream in a Writer so the JSp engine can use the Writer it is expecting to use.
*/
out = new PrintWriter(response.getOutputStream());
}
}
}
@Override
public final void clear() throws IOException {
if ((bufferSize == 0) && (out != null)) {
// clear() is illegal after any unbuffered output (JSP.5.5)
throw new IllegalStateException(
Localizer.getMessage("jsp.error.ise_on_clear"));
}
if (flushed) {
throw new IOException(
Localizer.getMessage("jsp.error.attempt_to_clear_flushed_buffer"));
}
ensureOpen();
nextChar = 0;
}
@Override
public void clearBuffer() throws IOException {
if (bufferSize == 0) {
throw new IllegalStateException(
Localizer.getMessage("jsp.error.ise_on_clear"));
}
ensureOpen();
nextChar = 0;
}
private void bufferOverflow() throws IOException {
throw new IOException(Localizer.getMessage("jsp.error.overflow"));
}
@Override
public void flush() throws IOException {
flushBuffer();
if (out != null) {
out.flush();
}
}
@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;
}
@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(Localizer.getMessage("jsp.error.stream.closed"));
}
}
@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;
}
@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();
}
}
}
}
@Override
public void write(char buf[]) throws IOException {
write(buf, 0, buf.length);
}
@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();
}
}
}
}
@Override
public void newLine() throws IOException {
write(System.lineSeparator());
}
/* Methods that do not terminate lines */
@Override
public void print(boolean b) throws IOException {
write(b ? "true" : "false");
}
@Override
public void print(char c) throws IOException {
write(String.valueOf(c));
}
@Override
public void print(int i) throws IOException {
write(String.valueOf(i));
}
@Override
public void print(long l) throws IOException {
write(String.valueOf(l));
}
@Override
public void print(float f) throws IOException {
write(String.valueOf(f));
}
@Override
public void print(double d) throws IOException {
write(String.valueOf(d));
}
@Override
public void print(char s[]) throws IOException {
write(s);
}
@Override
public void print(String s) throws IOException {
if (s == null) {
s = "null";
}
write(s);
}
@Override
public void print(Object obj) throws IOException {
write(String.valueOf(obj));
}
/* Methods that do terminate lines */
@Override
public void println() throws IOException {
newLine();
}
@Override
public void println(boolean x) throws IOException {
print(x);
println();
}
@Override
public void println(char x) throws IOException {
print(x);
println();
}
@Override
public void println(int x) throws IOException {
print(x);
println();
}
@Override
public void println(long x) throws IOException {
print(x);
println();
}
@Override
public void println(float x) throws IOException {
print(x);
println();
}
@Override
public void println(double x) throws IOException {
print(x);
println();
}
@Override
public void println(char x[]) throws IOException {
print(x);
println();
}
@Override
public void println(String x) throws IOException {
print(x);
println();
}
@Override
public void println(Object x) throws IOException {
print(x);
println();
}
}