ThrottlingHttpClientHandler

Class Overview

Client protocol handler implementation that provide compatibility with the blocking I/O by utilizing shared content buffers and a fairly small pool of worker threads. The throttling protocol handler allocates input / output buffers of a constant length upon initialization and controls the rate of I/O events in order to ensure those content buffers do not ever get overflown. This helps ensure nearly constant memory footprint for HTTP connections and avoid the out of memory condition while streaming content in and out. The handleResponse(HttpResponse, HttpContext) method will fire immediately when a message is received. The protocol handler delegate the task of processing requests and generating response content to an Executor, which is expected to perform those tasks using dedicated worker threads in order to avoid blocking the I/O thread.

Usually throttling protocol handlers need only a modest number of worker threads, much fewer than the number of concurrent connections. If the length of the message is smaller or about the size of the shared content buffer worker thread will just store content in the buffer and terminate almost immediately without blocking. The I/O dispatch thread in its turn will take care of sending out the buffered content asynchronously. The worker thread will have to block only when processing large messages and the shared buffer fills up. It is generally advisable to allocate shared buffers of a size of an average content body for optimal performance.

The following parameters can be used to customize the behavior of this class:

• WAIT_FOR_CONTINUE
• CONTENT_BUFFER_SIZE

Summary

[Expand] Inherited Constants
From class org.apache.http.nio.protocol.NHttpHandlerBase String CONN_STATE

[Expand] Inherited Fields
From class org.apache.http.nio.protocol.NHttpHandlerBase protected final ByteBufferAllocator allocator protected final ConnectionReuseStrategy connStrategy protected EventListener eventListener protected final HttpProcessor httpProcessor protected final HttpParams params

[Expand] Inherited Methods
From class org.apache.http.nio.protocol.NHttpHandlerBase boolean canResponseHaveBody(HttpRequest request, HttpResponse response) void closeConnection(NHttpConnection conn, Throwable cause) HttpParams getParams() void handleTimeout(NHttpConnection conn) void setEventListener(EventListener eventListener) void shutdownConnection(NHttpConnection conn, Throwable cause)
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait() final void wait(long arg0, int arg1) final void wait(long arg0)
From interface org.apache.http.nio.NHttpClientHandler abstract void closed(NHttpClientConnection conn) Triggered when the connection is closed. abstract void connected(NHttpClientConnection conn, Object attachment) Triggered when a new outgoing connection is created. abstract void exception(NHttpClientConnection conn, HttpException ex) Triggered when an HTTP protocol violation occurs while receiving an HTTP response. abstract void exception(NHttpClientConnection conn, IOException ex) Triggered when an I/O error occurs while reading from or writing to the underlying channel. abstract void inputReady(NHttpClientConnection conn, ContentDecoder decoder) Triggered when the underlying channel is ready for reading a new portion of the response entity through the corresponding content decoder. abstract void outputReady(NHttpClientConnection conn, ContentEncoder encoder) Triggered when the underlying channel is ready for writing a next portion of the request entity through the corresponding content encoder. abstract void requestReady(NHttpClientConnection conn) Triggered when the connection is ready to accept a new HTTP request. abstract void responseReceived(NHttpClientConnection conn) Triggered when an HTTP response is received. abstract void timeout(NHttpClientConnection conn) Triggered when no input is detected on this connection over the maximum period of inactivity.