+ * The following parameters can be used to customize the behavior of this + * class: + *
+ * This constructor will invoke {@link #createEntityDeserializer()} + * and {@link #createEntitySerializer()} methods in order to initialize + * HTTP entity serializer and deserializer implementations for this + * connection. + */ + public AbstractHttpClientConnection() { + super(); + this.entityserializer = createEntitySerializer(); + this.entitydeserializer = createEntityDeserializer(); + } + + /** + * Asserts if the connection is open. + * + * @throws IllegalStateException if the connection is not open. + */ + protected abstract void assertOpen() throws IllegalStateException; + + /** + * Creates an instance of {@link EntityDeserializer} with the + * {@link LaxContentLengthStrategy} implementation to be used for + * de-serializing entities received over this connection. + *
+ * This method can be overridden in a super class in order to create + * instances of {@link EntityDeserializer} using a custom + * {@link ContentLengthStrategy}. + * + * @return HTTP entity deserializer + */ + protected EntityDeserializer createEntityDeserializer() { + return new EntityDeserializer(new LaxContentLengthStrategy()); + } + + /** + * Creates an instance of {@link EntitySerializer} with the + * {@link StrictContentLengthStrategy} implementation to be used for + * serializing HTTP entities sent over this connection. + *
+ * This method can be overridden in a super class in order to create + * instances of {@link EntitySerializer} using a custom + * {@link ContentLengthStrategy}. + * + * @return HTTP entity serialzier. + */ + protected EntitySerializer createEntitySerializer() { + return new EntitySerializer(new StrictContentLengthStrategy()); + } + + /** + * Creates an instance of {@link DefaultHttpResponseFactory} to be used + * for creating {@link HttpResponse} objects received by over this + * connection. + *
+ * This method can be overridden in a super class in order to provide + * a different implementation of the {@link HttpResponseFactory} interface. + * + * @return HTTP response factory. + */ + protected HttpResponseFactory createHttpResponseFactory() { + return new DefaultHttpResponseFactory(); + } + + /** + * Creates an instance of {@link HttpMessageParser} to be used for parsing + * HTTP responses received over this connection. + *
+ * This method can be overridden in a super class in order to provide + * a different implementation of the {@link HttpMessageParser} interface or + * to pass a different implementation of {@link LineParser} to the + * the default implementation {@link HttpResponseParser}. + * + * @param buffer the session input buffer. + * @param responseFactory the HTTP response factory. + * @param params HTTP parameters. + * @return HTTP message parser. + */ + protected HttpMessageParser createResponseParser( + final SessionInputBuffer buffer, + final HttpResponseFactory responseFactory, + final HttpParams params) { + return new HttpResponseParser(buffer, null, responseFactory, params); + } + + /** + * Creates an instance of {@link HttpMessageWriter} to be used for + * writing out HTTP requests sent over this connection. + *
+ * This method can be overridden in a super class in order to provide + * a different implementation of the {@link HttpMessageWriter} interface or + * to pass a different implementation of {@link LineFormatter} to the + * the default implementation {@link HttpRequestWriter}. + * + * @param buffer the session output buffer + * @param params HTTP parameters + * @return HTTP message writer + */ + protected HttpMessageWriter createRequestWriter( + final SessionOutputBuffer buffer, + final HttpParams params) { + return new HttpRequestWriter(buffer, null, params); + } + + /** + * @since 4.1 + */ + protected HttpConnectionMetricsImpl createConnectionMetrics( + final HttpTransportMetrics inTransportMetric, + final HttpTransportMetrics outTransportMetric) { + return new HttpConnectionMetricsImpl(inTransportMetric, outTransportMetric); + } + + /** + * Initializes this connection object with {@link SessionInputBuffer} and + * {@link SessionOutputBuffer} instances to be used for sending and + * receiving data. These session buffers can be bound to any arbitrary + * physical output medium. + *
+ * This method will invoke {@link #createHttpResponseFactory()}, + * {@link #createRequestWriter(SessionOutputBuffer, HttpParams)} + * and {@link #createResponseParser(SessionInputBuffer, HttpResponseFactory, HttpParams)} + * methods to initialize HTTP request writer and response parser for this + * connection. + * + * @param inbuffer the session input buffer. + * @param outbuffer the session output buffer. + * @param params HTTP parameters. + */ + protected void init( + final SessionInputBuffer inbuffer, + final SessionOutputBuffer outbuffer, + final HttpParams params) { + if (inbuffer == null) { + throw new IllegalArgumentException("Input session buffer may not be null"); + } + if (outbuffer == null) { + throw new IllegalArgumentException("Output session buffer may not be null"); + } + this.inbuffer = inbuffer; + this.outbuffer = outbuffer; + if (inbuffer instanceof EofSensor) { + this.eofSensor = (EofSensor) inbuffer; + } + this.responseParser = createResponseParser( + inbuffer, + createHttpResponseFactory(), + params); + this.requestWriter = createRequestWriter( + outbuffer, params); + this.metrics = createConnectionMetrics( + inbuffer.getMetrics(), + outbuffer.getMetrics()); + } + + public boolean isResponseAvailable(int timeout) throws IOException { + assertOpen(); + return this.inbuffer.isDataAvailable(timeout); + } + + public void sendRequestHeader(final HttpRequest request) + throws HttpException, IOException { + if (request == null) { + throw new IllegalArgumentException("HTTP request may not be null"); + } + assertOpen(); + this.requestWriter.write(request); + this.metrics.incrementRequestCount(); + } + + public void sendRequestEntity(final HttpEntityEnclosingRequest request) + throws HttpException, IOException { + if (request == null) { + throw new IllegalArgumentException("HTTP request may not be null"); + } + assertOpen(); + if (request.getEntity() == null) { + return; + } + this.entityserializer.serialize( + this.outbuffer, + request, + request.getEntity()); + } + + protected void doFlush() throws IOException { + this.outbuffer.flush(); + } + + public void flush() throws IOException { + assertOpen(); + doFlush(); + } + + public HttpResponse receiveResponseHeader() + throws HttpException, IOException { + assertOpen(); + HttpResponse response = (HttpResponse) this.responseParser.parse(); + if (response.getStatusLine().getStatusCode() >= 200) { + this.metrics.incrementResponseCount(); + } + return response; + } + + public void receiveResponseEntity(final HttpResponse response) + throws HttpException, IOException { + if (response == null) { + throw new IllegalArgumentException("HTTP response may not be null"); + } + assertOpen(); + HttpEntity entity = this.entitydeserializer.deserialize(this.inbuffer, response); + response.setEntity(entity); + } + + protected boolean isEof() { + return this.eofSensor != null && this.eofSensor.isEof(); + } + + public boolean isStale() { + if (!isOpen()) { + return true; + } + if (isEof()) { + return true; + } + try { + this.inbuffer.isDataAvailable(1); + return isEof(); + } catch (IOException ex) { + return true; + } + } + + public HttpConnectionMetrics getMetrics() { + return this.metrics; + } + +}