All Implemented Interfaces:
A Context represents the state information that is accessed and manipulated by the execution of a Command or a Chain . Specialized implementations of Context will typically add JavaBeans properties that contain typesafe accessors to information that is relevant to a particular use case for this context, and/or add operations that affect the state information that is saved in the context.
Implementations of Context must also implement all of the
required and optional contracts of the
It is strongly recommended, but not required, that JavaBeans
properties added to a particular Context implementation exhibit
Attribute-Property Transparency. In other words,
a value stored via a call to
setFoo(value) should be visible
get("foo"), and a value stored
via a call to
put("foo", value) should be
visible by calling
getFoo(). If your Context
implementation class exhibits this featue, it becomes easier to reuse the
implementation in multiple environments, without the need to cast to a
particular implementation class in order to access the property getter
and setter methods.
To protect applications from evolution of this interface, specialized implementations of Context should generally be created by extending the provided base class (org.apache.commons.chain.impl.ContextBase ) rather than directly implementing this interface.
Applications should NOT assume that Context implementations, or the values stored in its attributes, may be accessed from multiple threads simultaneously unless this is explicitly documented for a particular implementation.
Craig- R. McClanahan
$- Revision: 480477 $ $Date: 2006-11-29 08:34:52 +0000 (Wed, 29 Nov 2006) $