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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.DoubleValue;
import com.yahoo.searchlib.rankingexpression.evaluation.Value;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Deque;
import java.util.List;
/**
* Invocation of a native function.
*
* @author simon
* @author bratseth
*/
public final class FunctionNode extends CompositeNode {
/** The type of function. */
private final Function function;
/** The arguments to this function. */
private final Arguments arguments;
/* Creates an unary function node */
public FunctionNode(Function function, ExpressionNode argument) {
if (function.arity() != 1) throw new IllegalArgumentException(function + " is not unary");
this.function = function;
this.arguments = new Arguments(Collections.singletonList(argument));
}
/** Creates a binary function node */
public FunctionNode(Function function, ExpressionNode argument1, ExpressionNode argument2) {
if (function.arity() != 2) throw new IllegalArgumentException(function + " is not binary");
this.function = function;
List<ExpressionNode> argumentList = new ArrayList<>();
argumentList.add(argument1);
argumentList.add(argument2);
arguments=new Arguments(argumentList);
}
public Function getFunction() { return function; }
/** Returns the arguments of this */
@Override
public List<ExpressionNode> children() {
return arguments.expressions();
}
@Override
public String toString(SerializationContext context, Deque<String> path, CompositeNode parent) {
StringBuilder b=new StringBuilder(function.toString());
b.append("(");
for (int i = 0; i < this.arguments.expressions().size(); ++i) {
b.append(this.arguments.expressions().get(i).toString(context, path, this));
if (i < this.arguments.expressions().size() - 1) {
b.append(",");
}
}
b.append(")");
return b.toString();
}
@Override
public Value evaluate(Context context) {
if (arguments.expressions().size() == 0)
return DoubleValue.zero.function(function,DoubleValue.zero);
Value argument1 = arguments.expressions().get(0).evaluate(context);
if (arguments.expressions().size() == 1)
return argument1.function(function, DoubleValue.zero);
Value argument2 = arguments.expressions().get(1).evaluate(context);
return argument1.function(function,argument2);
}
/** Returns a new function node with the children replaced by the given children */
@Override
public FunctionNode setChildren(List<ExpressionNode> children) {
if (arguments.expressions().size() != children.size())
throw new IllegalArgumentException("Expected " + arguments.expressions().size() + " children but got " + children.size());
if (children.size() == 1)
return new FunctionNode(function, children.get(0));
else // binary
return new FunctionNode(function, children.get(0), children.get(1));
}
}
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