org.apache.http.impl
Class DefaultConnectionReuseStrategy

java.lang.Object
  extended by org.apache.http.impl.DefaultConnectionReuseStrategy
All Implemented Interfaces:
ConnectionReuseStrategy

@Immutable
public class DefaultConnectionReuseStrategy
extends Object
implements ConnectionReuseStrategy

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.

Since:
4.0

Field Summary
static DefaultConnectionReuseStrategy INSTANCE
           
 
Constructor Summary
DefaultConnectionReuseStrategy()
           
 
Method Summary
protected  TokenIterator createTokenIterator(HeaderIterator hit)
          Creates a token iterator from a header iterator.
 boolean keepAlive(HttpResponse response, HttpContext context)
          Decides whether a connection can be kept open after a request.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

INSTANCE

public static final DefaultConnectionReuseStrategy INSTANCE
Constructor Detail

DefaultConnectionReuseStrategy

public DefaultConnectionReuseStrategy()
Method Detail

keepAlive

public boolean keepAlive(HttpResponse response,
                         HttpContext context)
Description copied from interface: ConnectionReuseStrategy
Decides whether a connection can be kept open after a request. If this method returns false, the caller MUST close the connection to correctly comply with the HTTP protocol. If it returns true, the caller SHOULD attempt to keep the connection open for reuse with another request.

One can use the HTTP context to retrieve additional objects that may be relevant for the keep-alive strategy: the actual HTTP connection, the original HTTP request, target host if known, number of times the connection has been reused already and so on.

If the connection is already closed, false is returned. The stale connection check MUST NOT be triggered by a connection reuse strategy.

Specified by:
keepAlive in interface ConnectionReuseStrategy
Parameters:
response - The last response received over that connection.
context - the context in which the connection is being used.
Returns:
true if the connection is allowed to be reused, or false if it MUST NOT be reused

createTokenIterator

protected TokenIterator createTokenIterator(HeaderIterator hit)
Creates a token iterator from a header iterator. This method can be overridden to replace the implementation of the token iterator.

Parameters:
hit - the header iterator
Returns:
the token iterator


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