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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.searchlib.rankingexpression.rule;
import com.yahoo.searchlib.rankingexpression.evaluation.Context;
import com.yahoo.searchlib.rankingexpression.evaluation.Value;
import java.util.*;
/**
* A conditional branch of a ranking expression.
*
* @author <a href="mailto:simon@yahoo-inc.com">Simon Thoresen</a>
* @author bratseth
*/
public final class IfNode extends CompositeNode {
/** The expression nodes that make up this condition. */
private final ExpressionNode condition, trueExpression, falseExpression;
private final Double trueProbability;
public IfNode(ExpressionNode condition, ExpressionNode trueExpression, ExpressionNode falseExpression) {
this(condition, trueExpression, falseExpression, null);
}
/**
* Creates a new condition node.
*
* @param condition the condition of this
* @param trueExpression the expression to evaluate if the comparison is true
* @param falseExpression the expression to evaluate if the comparison is false
* @param trueProbability the probability that the condition will evaluate to true, or null if not known.
* @throws IllegalArgumentException if trueProbability is non-null and not between 0.0 and 1.0
*/
public IfNode(ExpressionNode condition, ExpressionNode trueExpression, ExpressionNode falseExpression,
Double trueProbability) {
if (trueProbability != null && ( trueProbability < 0.0 || trueProbability > 1.0) )
throw new IllegalArgumentException("trueProbability must be a between 0.0 and 1.0, not " + trueProbability);
this.condition = condition;
this.trueProbability = trueProbability;
this.trueExpression = trueExpression;
this.falseExpression = falseExpression;
}
@Override
public List<ExpressionNode> children() {
List<ExpressionNode> children = new ArrayList<ExpressionNode>(4);
children.add(condition);
children.add(trueExpression);
children.add(falseExpression);
return Collections.unmodifiableList(children);
}
public ExpressionNode getCondition() { return condition; }
public ExpressionNode getTrueExpression() { return trueExpression; }
public ExpressionNode getFalseExpression() { return falseExpression; }
/** The average probability that the condition of this node will evaluate to true, or null if not known */
public Double getTrueProbability() { return trueProbability; }
@Override
public String toString(SerializationContext context, Deque<String> path, CompositeNode parent) {
return "if (" +
condition.toString(context, path, this) + ", " +
trueExpression.toString(context, path, this) + ", " +
falseExpression.toString(context, path, this) +
(trueProbability != null ? ", " + trueProbability : "") + ")";
}
@Override
public Value evaluate(Context context) {
if (condition.evaluate(context).asBoolean())
return trueExpression.evaluate(context);
else
return falseExpression.evaluate(context);
}
@Override
public IfNode setChildren(List<ExpressionNode> children) {
if (children.size() != 3) throw new IllegalArgumentException("Expected 3 children but got " + children.size());
return new IfNode(children.get(0), children.get(1), children.get(2));
}
}
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