/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.com
*
* This program is free software: you can redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License along with this program.
* If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.tools.expression.internal.function.text;
import java.util.concurrent.Callable;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.expression.DoubleCallable;
import com.rapidminer.tools.expression.ExpressionEvaluator;
import com.rapidminer.tools.expression.ExpressionParsingException;
import com.rapidminer.tools.expression.ExpressionType;
import com.rapidminer.tools.expression.FunctionDescription;
import com.rapidminer.tools.expression.FunctionInputException;
import com.rapidminer.tools.expression.internal.SimpleExpressionEvaluator;
import com.rapidminer.tools.expression.internal.function.AbstractFunction;
/**
*
* Abstract class for a {@link Function} that has two string arguments and returns an integer
* argument.
*
* @author David Arnu
*
*/
public abstract class Abstract2StringInputIntegerOutputFunction extends AbstractFunction {
/**
* Constructs an AbstractFunction with {@link FunctionDescription} generated from the arguments
* and the function name generated from the description.
*
* @param i18nKey
* the key for the {@link FunctionDescription}. The functionName is read from
* "gui.dialog.function.i18nKey.name", the helpTextName from ".help", the groupName
* from ".group", the description from ".description" and the function with
* parameters from ".parameters". If ".parameters" is not present, the ".name" is
* taken for the function with parameters.
* @param numberOfArgumentsToCheck
* the fixed number of parameters this functions expects or -1
*/
public Abstract2StringInputIntegerOutputFunction(String i18n, int numberOfArgumentsToCheck) {
super(i18n, numberOfArgumentsToCheck, Ontology.INTEGER);
}
@Override
public ExpressionEvaluator compute(ExpressionEvaluator... inputEvaluators) {
if (inputEvaluators.length != 2) {
throw new FunctionInputException("expression_parser.function_wrong_input", getFunctionName(), 2,
inputEvaluators.length);
}
ExpressionType type = getResultType(inputEvaluators);
ExpressionEvaluator left = inputEvaluators[0];
ExpressionEvaluator right = inputEvaluators[1];
return new SimpleExpressionEvaluator(makeStringCallable(left, right), type, isResultConstant(inputEvaluators));
}
/**
* Builds a DoubleCallable from left and right using {@link #compute(String, String)}, where
* constant child results are evaluated.
*
* @param left
* the left input
* @param right
* the right input
* @return the resulting DoubleCallable
*/
protected DoubleCallable makeStringCallable(ExpressionEvaluator left, ExpressionEvaluator right) {
final Callable<String> funcLeft = left.getStringFunction();
final Callable<String> funcRight = right.getStringFunction();
try {
final String valueLeft = left.isConstant() ? funcLeft.call() : "";
final String valueRight = right.isConstant() ? funcRight.call() : "";
if (left.isConstant() && right.isConstant()) {
final double result = compute(valueLeft, valueRight);
return new DoubleCallable() {
@Override
public double call() throws Exception {
return result;
}
};
} else if (left.isConstant()) {
return new DoubleCallable() {
@Override
public double call() throws Exception {
return compute(valueLeft, funcRight.call());
}
};
} else if (right.isConstant()) {
return new DoubleCallable() {
@Override
public double call() throws Exception {
return compute(funcLeft.call(), valueRight);
}
};
} else {
return new DoubleCallable() {
@Override
public double call() throws Exception {
return compute(funcLeft.call(), funcRight.call());
}
};
}
} catch (ExpressionParsingException e) {
throw e;
} catch (Exception e) {
throw new ExpressionParsingException(e);
}
}
/**
* Computes the result for two input String values.
*
* @param value1
* @param value2
* @return the result of the computation.
*/
protected abstract double compute(String value1, String value2);
@Override
protected ExpressionType computeType(ExpressionType... inputTypes) {
ExpressionType left = inputTypes[0];
ExpressionType right = inputTypes[1];
if (left == ExpressionType.STRING && right == ExpressionType.STRING) {
return ExpressionType.INTEGER;
} else {
throw new FunctionInputException("expression_parser.function_wrong_type", getFunctionName(), "nominal");
}
}
}