Package org.drools.compiler.builder.impl

Class EvaluatorRegistry

java.lang.Object
org.drools.compiler.builder.impl.EvaluatorRegistry
All Implemented Interfaces:
Externalizable, Serializable
public class EvaluatorRegistry extends Object implements Externalizable
A registry class for all available evaluators
See Also:

  • Constructor Details

    • EvaluatorRegistry

      public EvaluatorRegistry()
      Default constructor. The registry will use the context classloader (if available) to load the evaluator definition classes or this class classloader if it is not available.

    • EvaluatorRegistry

      public EvaluatorRegistry(ClassLoader classloader)
      Creates a new EvaluatorRegistry using the given classloader to load the evaluator definition classes.
      Parameters:
      classloader - the classloader to use to load evaluator definition classes. If it is null, try to obtain the context classloader. If it is also null, uses the same classloader that loaded this class.

  • Method Details

    • keySet

      public Set<String> keySet()
      Return the set of registered keys.
      Returns:
      a Set of Strings

    • readExternal

      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      Specified by:
      readExternal in interface Externalizable
      Throws:
      IOException
      ClassNotFoundException

    • writeExternal

      public void writeExternal(ObjectOutput out) throws IOException
      Specified by:
      writeExternal in interface Externalizable
      Throws:
      IOException

    • addEvaluatorDefinition

      public void addEvaluatorDefinition(String className)
      Adds an evaluator definition class to the registry using the evaluator class name. The class will be loaded and the corresponting evaluator ID will be added to the registry. In case there exists an implementation for that ID already, the new implementation will replace the previous one.
      Parameters:
      className - the name of the class for the implementation definition. The class must implement the EvaluatorDefinition interface.

    • addEvaluatorDefinition

      public void addEvaluatorDefinition(EvaluatorDefinition def)
      Adds an evaluator definition class to the registry. In case there exists an implementation for that evaluator ID already, the new implementation will replace the previous one.
      Parameters:
      def - the evaluator definition to be added.

    • getEvaluatorDefinition

      public EvaluatorDefinition getEvaluatorDefinition(String evaluatorId)
      Returns the evaluator definition for the given evaluator ID or null if no one was found
      Parameters:
      evaluatorId -
      Returns:

    • getEvaluatorDefinition

      public EvaluatorDefinition getEvaluatorDefinition(Operator operator)
      Returns the evaluator definition for the given operator or null if no one was found
      Parameters:
      operator - the operator implemented by the evaluator definition
      Returns:

    • getEvaluator

      public Evaluator getEvaluator(ValueType type, String operatorId, boolean isNegated, String parameterText)
      Returns the evaluator instance for the given type and the defined parameterText
      Parameters:
      type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimizations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.
      operatorId - the string identifier of the evaluator
      isNegated - true if the evaluator instance to be returned is the negated version of the evaluator.
      parameterText - some evaluators support parameters and these parameters are defined as a String that is parsed by the evaluator itself.
      Returns:
      an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

    • getEvaluator

      public Evaluator getEvaluator(ValueType type, Operator operator, String parameterText)
      Returns the evaluator instance for the given type and the defined parameterText
      Parameters:
      type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimizations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.
      operator - the operator that evaluator implements
      parameterText - some evaluators support parameters and these parameters are defined as a String that is parsed by the evaluator itself.
      Returns:
      an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

    • getEvaluator

      public Evaluator getEvaluator(ValueType type, Operator operator)
      Returns the evaluator instance for the given type and the defined parameterText
      Parameters:
      type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimizations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.
      operator - the operator that evaluator implements
      Returns:
      an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.