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package org.glassfish.jersey.jdk.connector;
import org.glassfish.jersey.internal.util.collection.NonBlockingInputStream;
/**
* TODO consider exposing the mode as part of the API, so the user can make decisions based on the mode
* <p/>
* An extension of {@link NonBlockingInputStream} that adds methods that enable using the stream asynchronously.
* The asynchronous mode is inspired by and works in a very similar way as Servlet asynchronous streams introduced in Servlet
* 3.1.
* <p/>
* The stream supports 2 modes of operation SYNCHRONOUS and ASYNCHRONOUS.
* The stream is one of the following 3 states:
* <ul>
* <li>UNDECIDED</li>
* <li>SYNCHRONOUS</li>
* <li>ASYNCHRONOUS</li>
* </ul>
* UNDECIDED is an initial mode and it commits either to SYNCHRONOUS or ASYNCHRONOUS. Once it commits to one of these
* 2 modes it cannot change to the other. The mode it commits to is decided based on the first use of te stream.
* If {@link #setReadListener(ReadListener)} is invoked before any of the read or tryRead methods, it commits to ASYNCHRONOUS
* mode and similarly if any of the read or tryRead methods is invoked before {@link #setReadListener(ReadListener)},
* it commits to SYNCHRONOUS mode.
*/
abstract class BodyInputStream extends NonBlockingInputStream {
/**
* Returns true if data can be read without blocking else returns
* false.
* <p/>
* If the stream is in ASYNCHRONOUS mode and the user attempts to read from it even though this method returns
* false, an {@link IllegalStateException} is thrown.
*
* @return <code>true</code> if data can be obtained without blocking,
* otherwise returns <code>false</code>.
*/
public abstract boolean isReady();
/**
* Instructs the stream to invoke the provided {@link ReadListener} when it is possible to read.
* <p/>
* If the stream is in UNDECIDED state, invoking this method will commit the stream to ASYNCHRONOUS mode.
*
* @param readListener the {@link ReadListener} that should be notified
* when it's possible to read.
* @throws IllegalStateException if one of the following conditions is true
* <ul>
* <li>the stream has already committed to SYNCHRONOUS mode. <li/>
* <li>setReadListener is called more than once within the scope of the same request. <li/>
* </ul>
* @throws NullPointerException if readListener is null
*/
public abstract void setReadListener(ReadListener readListener);
}