com.db4o.query

Interface Evaluation

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

PredicateEvaluation

public interface Evaluation
extends java.io.Serializable

for implementation of callback evaluations.

To constrain a Query node with your own callback Evaluation, construct an object that implements the Evaluation interface and register it by passing it to Query.constrain(Object).

Evaluations are called as the last step during query execution, after all other constraints have been applied. Evaluations in higher level Query nodes in the query graph are called first.

Java client/server only:
db4o first attempts to use Java Serialization to allow to pass final variables to the server. Please make sure that all variables that are used within the evaluate(Candidate) method are Serializable. This may include the class an anonymous Evaluation object is created in. If db4o is not successful at using Serialization, the Evaluation is transported to the server in a db4o MemoryBin. In this case final variables can not be restored.

Method Summary

Methods

Modifier and Type	Method and Description
void	evaluate(Candidate candidate) callback method during query execution.

Method Detail

evaluate

void evaluate(Candidate candidate)

callback method during query execution.

Parameters:

candidate - reference to the candidate persistent object.