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Jadex Rules is a small lightweight rule engine, which currently
employs the well-known Rete algorithm for highly efficient rule
matching. Jadex rules is therefore similar to other rule engines
like JESS and Drools. Despite the similarities there are also
important differences between these systems:
* Jadex Rules is very small and
intended to be used as component
of other software. Even though rules can be specified in a Java
dialect as well as (a small variation of) the CLIPS language
its primary usage is on the API level. Jadex Rules is currently
the core component of the Jadex BDI reasoning engine.
* Jadex Rules cleanly separates between state and rule representation.
This allows the state implementation as well as the matcher to be
flexibly exchanged. Some experiments have e.g. been conducted with
a Jena representation. Regarding the matcher, it is planned to
support also the Treat algorithm, which has a lower memory footprint
than Rete.
* Jadex Rules pays close attention to rule debugging. The state as
well as the rete engine can be observed at runtime. The rule debugger
provides functionalities to execute a rule program stepwise and also
use rule breakpoints to stop the execution at those points.
package jadex.rules.state.javaimpl;
import jadex.rules.state.OAVAttributeType;
/**
* Struct for storing an object usage.
* Identifies that a defined value (not part of this usage)
* is used in the defined object in the defined attribute.
*/
public class OAVObjectUsage
{
//-------- attributes --------
/** The object. */
protected Object object;
/** The attribute. */
protected OAVAttributeType attr;
/** External flag (i.e. referencing object is only externally referenced and no longer in state). */
protected boolean external;
//-------- constructors --------
/**
* Create a new object usage.
*/
public OAVObjectUsage(Object object, OAVAttributeType attr)
{
this.object = object;
this.attr = attr;
this.external = false;
}
//-------- methods --------
/**
* Get the object.
*/
public Object getObject()
{
return object;
}
/**
* Get the attribute.
*/
public OAVAttributeType getAttribute()
{
return attr;
}
/**
* Get the external flag.
*/
public boolean isExternal()
{
return external;
}
/**
* Set the external flag.
*/
public void setExternal(boolean external)
{
this.external = external;
}
/**
* Generate the hash code.
*/
public int hashCode()
{
int result = 31 + attr.hashCode();
result = 31 * result + object.hashCode();
return result;
}
/**
* Test if two objects are equal.
*/
public boolean equals(Object obj)
{
if(this == obj)
return true;
boolean ret = false;
if(obj instanceof OAVObjectUsage)
{
final OAVObjectUsage other = (OAVObjectUsage)obj;
ret = object.equals(other.getObject())
&& attr.equals(other.getAttribute());
}
return ret;
}
/**
* Create a string representation.
*/
public String toString()
{
return "Usage("+object+" "+attr.getName()+" )";
}
}