jakarta.servlet.ServletOutputStream Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2023 Oracle and/or its affiliates and others.
* All rights reserved.
* Copyright 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 jakarta.servlet;
import java.io.CharConversionException;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.text.MessageFormat;
import java.util.Objects;
import java.util.ResourceBundle;
/**
* Provides an output stream for sending binary data to the client. A ServletOutputStream object is
* normally retrieved via the {@link ServletResponse#getOutputStream} method.
*
*
* This is an abstract class that the servlet container implements. Subclasses of this class must implement the
* java.io.OutputStream.write(int) method.
*
*
* @author Various
*
* @see ServletResponse
*
*/
public abstract class ServletOutputStream extends OutputStream {
private static final String LSTRING_FILE = "jakarta.servlet.LocalStrings";
private static final ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);
/**
*
* Does nothing, because this is an abstract class.
*
*/
protected ServletOutputStream() {
}
/**
* Writes from the given buffer to the output stream.
*
* If the output steam is in non-blocking mode, before each invocation of this method {@link #isReady()} must be called
* and must return {@code true} or the {@link WriteListener#onWritePossible()} call back must indicate that data may be
* written else an {@link IllegalStateException} must be thrown.
*
* Otherwise, if this method is called when {@code buffer} has no data remaining, the method returns immediately and
* {@code buffer} is unchanged.
*
* If the output stream is in non-blocking mode, neither the position, limit nor content of the buffer passed to this
* method may be modified until a subsequent call to {@link #isReady()} returns true or the
* {@link WriteListener#onWritePossible()} call back indicates data may be written again. At this point the buffer's
* limit will be unchanged from the value when passed to this method and the position will be the same as the limit.
*
* If the output stream is in blocking mode and {@code buffer} has space remaining, this method blocks until all the
* remaining data in the buffer has been written. When the method returns, and if data has been written, the buffer's
* limit will be unchanged from the value when passed to this method and the position will be the same as the limit.
*
* Subclasses are strongly encouraged to override this method and provide a more efficient implementation.
*
* @param buffer The buffer from which the data is written.
*
* @exception IllegalStateException If the output stream is in non-blocking mode and this method is called without first
* calling {@link #isReady()} and that method has returned {@code true} or {@link WriteListener#onWritePossible()} has
* not signalled that data may be written.
*
* @exception IOException If the output stream has been closed or if some other I/O error occurs.
*
* @exception NullPointerException If buffer is null.
*
* @since Servlet 6.1
*/
public void write(ByteBuffer buffer) throws IOException {
Objects.requireNonNull(buffer);
if (!isReady()) {
throw new IllegalStateException();
}
if (buffer.remaining() == 0) {
return;
}
byte[] b = new byte[buffer.remaining()];
buffer.get(b);
write(b);
}
/**
* Writes a String to the client, without a carriage return-line feed (CRLF) character at the end.
*
*
* @param s the String to send to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void print(String s) throws IOException {
if (s == null)
s = "null";
int len = s.length();
byte[] out = new byte[len];
for (int i = 0; i < len; i++) {
char c = s.charAt(i);
//
// XXX NOTE: This is clearly incorrect for many strings,
// but is the only consistent approach within the current
// servlet framework. It must suffice until servlet output
// streams properly encode their output.
//
if ((c & 0xff00) != 0) { // high order byte must be zero
String errMsg = lStrings.getString("err.not_iso8859_1");
Object[] errArgs = new Object[1];
errArgs[0] = Character.valueOf(c);
errMsg = MessageFormat.format(errMsg, errArgs);
throw new CharConversionException(errMsg);
}
out[i] = (byte) (0xff & c);
}
write(out, 0, len);
}
/**
* Writes a boolean value to the client, with no carriage return-line feed (CRLF) character at the end.
*
* @param b the boolean value to send to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void print(boolean b) throws IOException {
print(lStrings.getString(b ? "value.true" : "value.false"));
}
/**
* Writes a character to the client, with no carriage return-line feed (CRLF) at the end.
*
* @param c the character to send to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void print(char c) throws IOException {
print(String.valueOf(c));
}
/**
*
* Writes an int to the client, with no carriage return-line feed (CRLF) at the end.
*
* @param i the int to send to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void print(int i) throws IOException {
print(String.valueOf(i));
}
/**
*
* Writes a long value to the client, with no carriage return-line feed (CRLF) at the end.
*
* @param l the long value to send to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void print(long l) throws IOException {
print(String.valueOf(l));
}
/**
*
* Writes a float value to the client, with no carriage return-line feed (CRLF) at the end.
*
* @param f the float value to send to the client
*
* @exception IOException if an input or output exception occurred
*
*
*/
public void print(float f) throws IOException {
print(String.valueOf(f));
}
/**
*
* Writes a double value to the client, with no carriage return-line feed (CRLF) at the end.
*
* @param d the double value to send to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void print(double d) throws IOException {
print(String.valueOf(d));
}
/**
* Writes a carriage return-line feed (CRLF) to the client.
*
*
*
* @exception IOException if an input or output exception occurred
*
*/
public void println() throws IOException {
print("\r\n");
}
/**
* Writes a String to the client, followed by a carriage return-line feed (CRLF).
*
*
* @param s the String to write to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(String s) throws IOException {
print(s == null ? "null\r\n" : (s + "\r\n"));
}
/**
*
* Writes a boolean value to the client, followed by a carriage return-line feed (CRLF).
*
*
* @param b the boolean value to write to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(boolean b) throws IOException {
println(lStrings.getString(b ? "value.true" : "value.false"));
}
/**
*
* Writes a character to the client, followed by a carriage return-line feed (CRLF).
*
* @param c the character to write to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(char c) throws IOException {
println(String.valueOf(c));
}
/**
*
* Writes an int to the client, followed by a carriage return-line feed (CRLF) character.
*
*
* @param i the int to write to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(int i) throws IOException {
println(String.valueOf(i));
}
/**
*
* Writes a long value to the client, followed by a carriage return-line feed (CRLF).
*
*
* @param l the long value to write to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(long l) throws IOException {
println(String.valueOf(l));
}
/**
*
* Writes a float value to the client, followed by a carriage return-line feed (CRLF).
*
* @param f the float value to write to the client
*
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(float f) throws IOException {
println(String.valueOf(f));
}
/**
*
* Writes a double value to the client, followed by a carriage return-line feed (CRLF).
*
*
* @param d the double value to write to the client
*
* @exception IOException if an input or output exception occurred
*
*/
public void println(double d) throws IOException {
println(String.valueOf(d));
}
/**
* Returns {@code true} if it is allowable to call any method that may write data (i.e. {@code write()}, {@code print()}
* {@code println()} or {@code flush}). In blocking mode, this method will always return {@code true}, but a subsequent
* call to a method that writes data may block. In non-blocking mode this method may return {@code false}, in which case
* it is illegal to call a method that writes data and an {@link IllegalStateException} MUST be thrown. When
* {@link WriteListener#onWritePossible()} is called, a call to this method that returned {@code true} is implicit.
*
* If this method returns {@code false} and a {@link WriteListener} has been set via
* {@link #setWriteListener(WriteListener)}, then container will subsequently invoke
* {@link WriteListener#onWritePossible()} once a write operation becomes possible without blocking. Other than the
* initial call, {@link WriteListener#onWritePossible()} will only be called if and only if this method is called and
* returns false.
*
* @return {@code true} if data can be written without blocking, otherwise returns {@code false}.
* @see WriteListener
* @since Servlet 3.1
*/
public abstract boolean isReady();
/**
* Instructs the ServletOutputStream to invoke the provided {@link WriteListener} when it is possible to
* write
*
*
* @param writeListener the {@link WriteListener} that should be notified when it's possible to write
*
* @exception IllegalStateException if one of the following conditions is true
*
* - the associated request is neither upgraded nor the async started
*
- setWriteListener is called more than once within the scope of the same request.
*
*
* @throws NullPointerException if writeListener is null
*
* @since Servlet 3.1
*/
public abstract void setWriteListener(WriteListener writeListener);
/**
* {@inheritDoc}
*
* If this method is called when the output stream is in non-blocking mode, it will immediately return with the stream
* effectively closed, even if the stream contains buffered data that is yet to be written to client. The container will
* write this data out in the background. If this process fails the {@link WriteListener#onError(Throwable)} method will
* be invoked as normal.
*/
@Override
public void close() throws IOException {
super.close();
}
}