Java tutorial
/* * Copyright 2009 Guenther Niess * * 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 com.chatsdk.kenai.jbosh; import java.io.IOException; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.ByteArrayEntity; import org.apache.http.protocol.BasicHttpContext; import org.apache.http.protocol.HttpContext; import org.apache.http.util.EntityUtils; final class ApacheHTTPResponse implements HTTPResponse { /////////////////////////////////////////////////////////////////////////// // Constants: /** * Name of the accept encoding header. */ private static final String ACCEPT_ENCODING = "Accept-Encoding"; /** * Value to use for the ACCEPT_ENCODING header. */ private static final String ACCEPT_ENCODING_VAL = ZLIBCodec.getID() + ", " + GZIPCodec.getID(); /** * Name of the character set to encode the body to/from. */ private static final String CHARSET = "UTF-8"; /** * Content type to use when transmitting the body data. */ private static final String CONTENT_TYPE = "text/xml; charset=utf-8"; /////////////////////////////////////////////////////////////////////////// // Class variables: /** * Lock used for internal synchronization. */ private final Lock lock = new ReentrantLock(); /** * The execution state of an HTTP process. */ private final HttpContext context; /** * HttpClient instance to use to communicate. */ private final HttpClient client; /** * The HTTP POST request is sent to the server. */ private final HttpPost post; /** * A flag which indicates if the transmission was already done. */ private boolean sent; /** * Exception to throw when the response data is attempted to be accessed, * or {@code null} if no exception should be thrown. */ private BOSHException toThrow; /** * The response body which was received from the server or {@code null} * if that has not yet happened. */ private AbstractBody body; /** * The HTTP response status code. */ private int statusCode; /////////////////////////////////////////////////////////////////////////// // Constructors: /** * Create and send a new request to the upstream connection manager, * providing deferred access to the results to be returned. * * @param client client instance to use when sending the request * @param cfg client configuration * @param params connection manager parameters from the session creation * response, or {@code null} if the session has not yet been established * @param request body of the client request */ ApacheHTTPResponse(final HttpClient client, final BOSHClientConfig cfg, final CMSessionParams params, final AbstractBody request) { super(); this.client = client; this.context = new BasicHttpContext(); this.post = new HttpPost(cfg.getURI().toString()); this.sent = false; try { String xml = request.toXML(); byte[] data = xml.getBytes(CHARSET); String encoding = null; if (cfg.isCompressionEnabled() && params != null) { AttrAccept accept = params.getAccept(); if (accept != null) { if (accept.isAccepted(ZLIBCodec.getID())) { encoding = ZLIBCodec.getID(); data = ZLIBCodec.encode(data); } else if (accept.isAccepted(GZIPCodec.getID())) { encoding = GZIPCodec.getID(); data = GZIPCodec.encode(data); } } } ByteArrayEntity entity = new ByteArrayEntity(data); entity.setContentType(CONTENT_TYPE); if (encoding != null) { entity.setContentEncoding(encoding); } post.setEntity(entity); if (cfg.isCompressionEnabled()) { post.setHeader(ACCEPT_ENCODING, ACCEPT_ENCODING_VAL); } } catch (Exception e) { toThrow = new BOSHException("Could not generate request", e); } } /////////////////////////////////////////////////////////////////////////// // HTTPResponse interface methods: /** * Abort the client transmission and response processing. */ public void abort() { if (post != null) { post.abort(); toThrow = new BOSHException("HTTP request aborted"); } } /** * Wait for and then return the response body. * * @return body of the response * @throws InterruptedException if interrupted while awaiting the response * @throws BOSHException on communication failure */ public AbstractBody getBody() throws InterruptedException, BOSHException { if (toThrow != null) { throw (toThrow); } lock.lock(); try { if (!sent) { awaitResponse(); } } finally { lock.unlock(); } return body; } /** * Wait for and then return the response HTTP status code. * * @return HTTP status code of the response * @throws InterruptedException if interrupted while awaiting the response * @throws BOSHException on communication failure */ public int getHTTPStatus() throws InterruptedException, BOSHException { if (toThrow != null) { throw (toThrow); } lock.lock(); try { if (!sent) { awaitResponse(); } } finally { lock.unlock(); } return statusCode; } /////////////////////////////////////////////////////////////////////////// // Package-private methods: /** * Await the response, storing the result in the instance variables of * this class when they arrive. * * @throws InterruptedException if interrupted while awaiting the response * @throws BOSHException on communication failure */ private synchronized void awaitResponse() throws BOSHException { HttpEntity entity = null; try { HttpResponse httpResp = client.execute(post, context); entity = httpResp.getEntity(); byte[] data = EntityUtils.toByteArray(entity); String encoding = entity.getContentEncoding() != null ? entity.getContentEncoding().getValue() : null; if (ZLIBCodec.getID().equalsIgnoreCase(encoding)) { data = ZLIBCodec.decode(data); } else if (GZIPCodec.getID().equalsIgnoreCase(encoding)) { data = GZIPCodec.decode(data); } body = StaticBody.fromString(new String(data, CHARSET)); statusCode = httpResp.getStatusLine().getStatusCode(); sent = true; } catch (IOException iox) { abort(); toThrow = new BOSHException("Could not obtain response", iox); throw (toThrow); } catch (RuntimeException ex) { abort(); throw (ex); } } }