/*
* Copyright (c) 1997-2018 Oracle and/or its affiliates. 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 javax.servlet;
import java.io.InputStream;
import java.io.IOException;
Provides an input stream for reading binary data from a client
request, including an efficient readLine method
for reading data one line at a time. With some protocols, such
as HTTP POST and PUT, a ServletInputStream
object can be used to read data sent from the client.
A ServletInputStream object is normally retrieved via the ServletRequest.getInputStream method.
This is an abstract class that a servlet container implements.
Subclasses of this class
must implement the java.io.InputStream.read() method.
Author: Various See Also:
/**
*
* Provides an input stream for reading binary data from a client
* request, including an efficient <code>readLine</code> method
* for reading data one line at a time. With some protocols, such
* as HTTP POST and PUT, a <code>ServletInputStream</code>
* object can be used to read data sent from the client.
*
* <p>A <code>ServletInputStream</code> object is normally retrieved via
* the {@link ServletRequest#getInputStream} method.
*
*
* <p>This is an abstract class that a servlet container implements.
* Subclasses of this class
* must implement the <code>java.io.InputStream.read()</code> method.
*
*
* @author Various
*
* @see ServletRequest
*
*/
public abstract class ServletInputStream extends InputStream {
Does nothing, because this is an abstract class.
/**
* Does nothing, because this is an abstract class.
*
*/
protected ServletInputStream() { }
Reads the input stream, one line at a time. Starting at an
offset, reads bytes into an array, until it reads a certain number
of bytes or reaches a newline character, which it reads into the
array as well.
This method returns -1 if it reaches the end of the input
stream before reading the maximum number of bytes.
Params: - b – an array of bytes into which data is read
- off – an integer specifying the character at which
this method begins reading
- len – an integer specifying the maximum number of
bytes to read
Throws: - IOException – if an input or output exception has occurred
Returns: an integer specifying the actual number of bytes
read, or -1 if the end of the stream is reached
/**
*
* Reads the input stream, one line at a time. Starting at an
* offset, reads bytes into an array, until it reads a certain number
* of bytes or reaches a newline character, which it reads into the
* array as well.
*
* <p>This method returns -1 if it reaches the end of the input
* stream before reading the maximum number of bytes.
*
*
*
* @param b an array of bytes into which data is read
*
* @param off an integer specifying the character at which
* this method begins reading
*
* @param len an integer specifying the maximum number of
* bytes to read
*
* @return an integer specifying the actual number of bytes
* read, or -1 if the end of the stream is reached
*
* @exception IOException if an input or output exception has occurred
*
*/
public int readLine(byte[] b, int off, int len) throws IOException {
if (len <= 0) {
return 0;
}
int count = 0, c;
while ((c = read()) != -1) {
b[off++] = (byte)c;
count++;
if (c == '\n' || count == len) {
break;
}
}
return count > 0 ? count : -1;
}
Returns true when all the data from the stream has been read else
it returns false.
Returns: true when all data for this particular request
has been read, otherwise returns false.Since: Servlet 3.1
/**
* Returns true when all the data from the stream has been read else
* it returns false.
*
* @return <code>true</code> when all data for this particular request
* has been read, otherwise returns <code>false</code>.
*
* @since Servlet 3.1
*/
public abstract boolean isFinished();
Returns true if data can be read without blocking else returns
false.
Returns: true if data can be obtained without blocking,
otherwise returns false.Since: Servlet 3.1
/**
* Returns true if data can be read without blocking else returns
* false.
*
* @return <code>true</code> if data can be obtained without blocking,
* otherwise returns <code>false</code>.
*
* @since Servlet 3.1
*/
public abstract boolean isReady();
Instructs the ServletInputStream to invoke the provided ReadListener when it is possible to read Params: - readListener – the
ReadListener that should be notified when it's possible to read.
Throws: - IllegalStateException – if one of the following conditions is true
- the associated request is neither upgraded nor the async started
- setReadListener is called more than once within the scope of the same request.
- NullPointerException – if readListener is null
Since: Servlet 3.1
/**
* Instructs the <code>ServletInputStream</code> to invoke the provided
* {@link ReadListener} when it is possible to read
*
* @param readListener the {@link ReadListener} that should be notified
* when it's possible to read.
*
* @exception IllegalStateException if one of the following conditions is true
* <ul>
* <li>the associated request is neither upgraded nor the async started
* <li>setReadListener is called more than once within the scope of the same request.
* </ul>
*
* @throws NullPointerException if readListener is null
*
* @since Servlet 3.1
*/
public abstract void setReadListener(ReadListener readListener);
}