/**
* 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.comparison;
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 comparison function that has 2 numerical or nominal inputs, but both of the
* same type
*
* @author Sabrina Kirstein
*
*/
public abstract class AbstractComparisonFunctionWith2Inputs extends AbstractFunction {
/**
* Constructs a comparison 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.
*/
public AbstractComparisonFunctionWith2Inputs(String i18nKey) {
super(i18nKey, 2, Ontology.BINOMINAL);
}
@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(makeBooleanCallable(left, right), isResultConstant(inputEvaluators), type);
}
/**
* Builds a boolean callable from evaluator using {@link #compute(double, double)} or
* {@link #compute(String, String)}, where constant child results are evaluated.
*
* @param left
* evaluator
* @param right
* evaluator
* @return the resulting boolean callable
*/
protected Callable<Boolean> makeBooleanCallable(ExpressionEvaluator left, ExpressionEvaluator right) {
ExpressionType leftType = left.getType();
ExpressionType rightType = right.getType();
try {
// if both types are numeric
if ((leftType.equals(ExpressionType.DOUBLE) || leftType.equals(ExpressionType.INTEGER))
&& (rightType.equals(ExpressionType.DOUBLE) || rightType.equals(ExpressionType.INTEGER))) {
final DoubleCallable funcLeft = left.getDoubleFunction();
final double valueLeft = left.isConstant() ? funcLeft.call() : Double.NaN;
final DoubleCallable funcRight = right.getDoubleFunction();
final double valueRight = right.isConstant() ? funcRight.call() : Double.NaN;
if (left.isConstant() && right.isConstant()) {
final boolean result = compute(valueLeft, valueRight);
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return result;
}
};
} else if (left.isConstant()) {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(valueLeft, funcRight.call());
}
};
} else if (right.isConstant()) {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcLeft.call(), valueRight);
}
};
} else {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcLeft.call(), funcRight.call());
}
};
}
// if both types are nominal
} else if (leftType.equals(ExpressionType.STRING) && rightType.equals(ExpressionType.STRING)) {
final Callable<String> funcLeft = left.getStringFunction();
final String valueLeft = left.isConstant() ? funcLeft.call() : null;
final Callable<String> funcRight = right.getStringFunction();
final String valueRight = right.isConstant() ? funcRight.call() : null;
if (left.isConstant() && right.isConstant()) {
final Boolean result = compute(valueLeft, valueRight);
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return result;
}
};
} else if (left.isConstant()) {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(valueLeft, funcRight.call());
}
};
} else if (right.isConstant()) {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcLeft.call(), valueRight);
}
};
} else {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcLeft.call(), funcRight.call());
}
};
}
} else {
return null;
}
} catch (ExpressionParsingException e) {
throw e;
} catch (Exception e) {
throw new ExpressionParsingException(e);
}
}
/**
* Computes the result for two double values.
*
* @param left
* value
* @param right
* value
* @return the result of the computation.
*/
protected abstract Boolean compute(double left, double right);
/**
* Computes the result for two String values.
*
* @param left
* value
* @param right
* value
* @return the result of the computation.
*/
protected abstract Boolean compute(String left, String right);
@Override
protected ExpressionType computeType(ExpressionType... inputTypes) {
if (inputTypes.length != 2) {
throw new FunctionInputException("expression_parser.function_wrong_input", getFunctionName(), "2",
inputTypes.length);
}
ExpressionType type1 = inputTypes[0];
ExpressionType type2 = inputTypes[1];
// types have to be the same
if (type1 != type2) {
if (!((type1 == ExpressionType.INTEGER || type1 == ExpressionType.DOUBLE) && (type2 == ExpressionType.INTEGER || type2 == ExpressionType.DOUBLE))) {
throw new FunctionInputException("expression_parser.function_needs_same_type", getFunctionName());
}
}
// type has to be numerical or nominal
for (ExpressionType inputType : inputTypes) {
if (inputType != ExpressionType.INTEGER && inputType != ExpressionType.DOUBLE
&& inputType != ExpressionType.STRING) {
throw new FunctionInputException("expression_parser.function_wrong_type", getFunctionName(),
"nominal or numerical");
}
}
// result is always boolean
return ExpressionType.BOOLEAN;
}
}