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Diffstat (limited to 'src/org/apache/http/impl/DefaultConnectionReuseStrategy.java')
| -rw-r--r-- | src/org/apache/http/impl/DefaultConnectionReuseStrategy.java | 182 |
1 files changed, 0 insertions, 182 deletions
diff --git a/src/org/apache/http/impl/DefaultConnectionReuseStrategy.java b/src/org/apache/http/impl/DefaultConnectionReuseStrategy.java deleted file mode 100644 index da1d5fd..0000000 --- a/src/org/apache/http/impl/DefaultConnectionReuseStrategy.java +++ /dev/null @@ -1,182 +0,0 @@ -/* - * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/impl/DefaultConnectionReuseStrategy.java $ - * $Revision: 602537 $ - * $Date: 2007-12-08 11:42:06 -0800 (Sat, 08 Dec 2007) $ - * - * ==================================================================== - * Licensed to the Apache Software Foundation (ASF) under one - * or more contributor license agreements. See the NOTICE file - * distributed with this work for additional information - * regarding copyright ownership. The ASF licenses this file - * to you 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. - * ==================================================================== - * - * This software consists of voluntary contributions made by many - * individuals on behalf of the Apache Software Foundation. For more - * information on the Apache Software Foundation, please see - * <http://www.apache.org/>. - * - */ - -package org.apache.http.impl; - -import org.apache.http.ConnectionReuseStrategy; -import org.apache.http.HttpConnection; -import org.apache.http.HeaderIterator; -import org.apache.http.HttpEntity; -import org.apache.http.HttpResponse; -import org.apache.http.HttpVersion; -import org.apache.http.ParseException; -import org.apache.http.ProtocolVersion; -import org.apache.http.protocol.HTTP; -import org.apache.http.protocol.HttpContext; -import org.apache.http.protocol.ExecutionContext; -import org.apache.http.TokenIterator; -import org.apache.http.message.BasicTokenIterator; - -/** - * Default implementation of a strategy deciding about connection re-use. - * The default implementation first checks some basics, for example - * whether the connection is still open or whether the end of the - * request entity can be determined without closing the connection. - * If these checks pass, the tokens in the "Connection" header will - * be examined. In the absence of a "Connection" header, the - * non-standard but commonly used "Proxy-Connection" header takes - * it's role. A token "close" indicates that the connection cannot - * be reused. If there is no such token, a token "keep-alive" indicates - * that the connection should be re-used. If neither token is found, - * or if there are no "Connection" headers, the default policy for - * the HTTP version is applied. Since HTTP/1.1, connections are re-used - * by default. Up until HTTP/1.0, connections are not re-used by default. - * - * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a> - * @author <a href="mailto:rolandw at apache.org">Roland Weber</a> - * - * @version $Revision: 602537 $ - * - * @since 4.0 - */ -public class DefaultConnectionReuseStrategy - implements ConnectionReuseStrategy { - - public DefaultConnectionReuseStrategy() { - super(); - } - - // see interface ConnectionReuseStrategy - public boolean keepAlive(final HttpResponse response, - final HttpContext context) { - if (response == null) { - throw new IllegalArgumentException - ("HTTP response may not be null."); - } - if (context == null) { - throw new IllegalArgumentException - ("HTTP context may not be null."); - } - - HttpConnection conn = (HttpConnection) - context.getAttribute(ExecutionContext.HTTP_CONNECTION); - - if (conn != null && !conn.isOpen()) - return false; - // do NOT check for stale connection, that is an expensive operation - - // Check for a self-terminating entity. If the end of the entity will - // be indicated by closing the connection, there is no keep-alive. - HttpEntity entity = response.getEntity(); - ProtocolVersion ver = response.getStatusLine().getProtocolVersion(); - if (entity != null) { - if (entity.getContentLength() < 0) { - if (!entity.isChunked() || - ver.lessEquals(HttpVersion.HTTP_1_0)) { - // if the content length is not known and is not chunk - // encoded, the connection cannot be reused - return false; - } - } - } - - // Check for the "Connection" header. If that is absent, check for - // the "Proxy-Connection" header. The latter is an unspecified and - // broken but unfortunately common extension of HTTP. - HeaderIterator hit = response.headerIterator(HTTP.CONN_DIRECTIVE); - if (!hit.hasNext()) - hit = response.headerIterator("Proxy-Connection"); - - // Experimental usage of the "Connection" header in HTTP/1.0 is - // documented in RFC 2068, section 19.7.1. A token "keep-alive" is - // used to indicate that the connection should be persistent. - // Note that the final specification of HTTP/1.1 in RFC 2616 does not - // include this information. Neither is the "Connection" header - // mentioned in RFC 1945, which informally describes HTTP/1.0. - // - // RFC 2616 specifies "close" as the only connection token with a - // specific meaning: it disables persistent connections. - // - // The "Proxy-Connection" header is not formally specified anywhere, - // but is commonly used to carry one token, "close" or "keep-alive". - // The "Connection" header, on the other hand, is defined as a - // sequence of tokens, where each token is a header name, and the - // token "close" has the above-mentioned additional meaning. - // - // To get through this mess, we treat the "Proxy-Connection" header - // in exactly the same way as the "Connection" header, but only if - // the latter is missing. We scan the sequence of tokens for both - // "close" and "keep-alive". As "close" is specified by RFC 2068, - // it takes precedence and indicates a non-persistent connection. - // If there is no "close" but a "keep-alive", we take the hint. - - if (hit.hasNext()) { - try { - TokenIterator ti = createTokenIterator(hit); - boolean keepalive = false; - while (ti.hasNext()) { - final String token = ti.nextToken(); - if (HTTP.CONN_CLOSE.equalsIgnoreCase(token)) { - return false; - } else if (HTTP.CONN_KEEP_ALIVE.equalsIgnoreCase(token)) { - // continue the loop, there may be a "close" afterwards - keepalive = true; - } - } - if (keepalive) - return true; - // neither "close" nor "keep-alive", use default policy - - } catch (ParseException px) { - // invalid connection header means no persistent connection - // we don't have logging in HttpCore, so the exception is lost - return false; - } - } - - // default since HTTP/1.1 is persistent, before it was non-persistent - return !ver.lessEquals(HttpVersion.HTTP_1_0); - } - - - /** - * Creates a token iterator from a header iterator. - * This method can be overridden to replace the implementation of - * the token iterator. - * - * @param hit the header iterator - * - * @return the token iterator - */ - protected TokenIterator createTokenIterator(HeaderIterator hit) { - return new BasicTokenIterator(hit); - } -} |