Package com.yahoo.searchlib.rankingexpression.evaluation

Class ExpressionOptimizer

java.lang.Object

com.yahoo.searchlib.rankingexpression.evaluation.ExpressionOptimizer

public class ExpressionOptimizer
extends Object

This class will perform various optimizations on the ranking expressions. Clients using optimized expressions will do // Set up once RankingExpression expression = new RankingExpression(myExpressionString); ArrayContext context = new ArrayContext(expression); new ExpressionOptimizer().optimize(expression, context); // Execute repeatedly context.put("featureName1", value1); ... expression.evaluate(context); // Note that the expression may be used by multiple threads at the same time, while the // context is single-threaded. To create a context for another tread, use the above context as a prototype, // contextForOtherThread = context.clone();

Instances of this class are not multithread safe.

Author:

bratseth

Constructor Summary

Constructors

Constructor	Description
ExpressionOptimizer()

Method Summary

Modifier and Type	Method	Description
Optimizer	getOptimizer(Class<?> clazz)	Gets an optimizer instance used by this by class name, or null if the optimizer is not known
OptimizationReport	optimize(RankingExpression expression, AbstractArrayContext arrayContext)
OptimizationReport	optimize(RankingExpression expression, ContextIndex contextIndex)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ExpressionOptimizer

public ExpressionOptimizer()

Method Details

getOptimizer

public Optimizer getOptimizer(Class<?> clazz)

Gets an optimizer instance used by this by class name, or null if the optimizer is not known

optimize

public OptimizationReport optimize(RankingExpression expression,
 ContextIndex contextIndex)

optimize

public OptimizationReport optimize(RankingExpression expression,
 AbstractArrayContext arrayContext)