com.sun.grizzly.ProtocolChain Maven / Gradle / Ivy
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package com.sun.grizzly;
/**
*
* This class implement the "Chain of Responsibility" pattern (for more info,
* take a look at the classic "Gang of Four" design patterns book). Towards
* that end, the Chain API models a computation as a series of "protocol filter"
* that can be combined into a "protocol chain".
*
* The API for ProtocolFilter consists of a two methods (execute() and
* postExecute) which is passed a "protocol context" parameter containing the
* dynamic state of the computation, and whose return value is a boolean
* that determines whether or not processing for the current chain has been
* completed (false), or whether processing should be delegated to the next
* ProtocolFilter in the chain (true). The owning ProtocolChain must call the
* postExectute() method of each ProtocolFilter in a ProtocolChain in reverse
* order of the invocation of their execute() methods.
*
* The following picture describe how it ProtocolFilter(s)
*
* -----------------------------------------------------------------------------
* - ProtocolFilter1.execute() --> ProtocolFilter2.execute() -------| -
* - | -
* - | -
* - | -
* - ProtocolFilter1.postExecute() <-- ProtocolFilter2.postExecute()| -
* -----------------------------------------------------------------------------
*
* The "context" abstraction is designed to isolate ProtocolFilter
* implementations from the environment in which they are run
* (such as a ProtocolFilter that can be used in either IIOP or HTTP parsing,
* without being tied directly to the API contracts of either of these
* environments). For ProtocolFilter that need to allocate resources prior to
* delegation, and then release them upon return (even if a delegated-to
* ProtocolFilter throws an exception), the "postExecute" method can be used
* for cleanup.
*
* @author Jeanfrancois Arcand
*/
public interface ProtocolChain{
/**
* {@link ProtocolChain} result attribute name.
*/
public static final String PROTOCOL_CHAIN_POST_INSTRUCTION =
"ChainPostInstruction";
/**
* Add a {@link ProtocolFilter} to the list. {@link ProtocolFilter}
* will be invoked in the order they have been added.
* @param protocolFilter {@link ProtocolFilter}
* @return {@link ProtocolFilter} added successfully (yes/no) ?
*/
public boolean addFilter(ProtocolFilter protocolFilter);
/**
* Remove the {@link ProtocolFilter} from this chain.
* @param theFilter {@link ProtocolFilter}
* @return {@link ProtocolFilter} removed successfully (yes/no) ?
*/
public boolean removeFilter(ProtocolFilter theFilter);
/**
* Insert a {@link ProtocolFilter} to the list at position 'pos'.
* @param pos The insertion position
* @param protocolFilter {@link ProtocolFilter}
*/
public void addFilter(int pos, ProtocolFilter protocolFilter);
/**
* Execute using the {@link Context} instance.
* @param context Context
* @throws java.lang.Exception
*/
public void execute(Context context) throws Exception;
}