/**
* 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.Date;
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;
/**
* Class for the MISSING function that has 1 arbitrary input
*
* @author Sabrina Kirstein
*/
public class Missing extends AbstractFunction {
/**
* Constructs a MISSING Function with 1 parameter with {@link FunctionDescription}
*/
public Missing() {
super("comparison.missing", 1, Ontology.BINOMINAL);
}
@Override
public ExpressionEvaluator compute(ExpressionEvaluator... inputEvaluators) {
if (inputEvaluators.length != 1) {
throw new FunctionInputException("expression_parser.function_wrong_input", getFunctionName(), "1",
inputEvaluators.length);
}
ExpressionType type = getResultType(inputEvaluators);
ExpressionEvaluator evaluator = inputEvaluators[0];
return new SimpleExpressionEvaluator(makeBooleanCallable(evaluator), isResultConstant(inputEvaluators), type);
}
/**
* Builds a boolean callable from a {@link ExpressionEvaluator}, where constant results are
* evaluated.
*
* @param evaluator
* @return the resulting boolean callable
*/
protected Callable<Boolean> makeBooleanCallable(ExpressionEvaluator evaluator) {
try {
// act depending on the type of the given evaluator
switch (evaluator.getType()) {
case INTEGER:
case DOUBLE:
final DoubleCallable funcDouble = evaluator.getDoubleFunction();
final double valueDouble = evaluator.isConstant() ? funcDouble.call() : Double.NaN;
if (evaluator.isConstant()) {
final Boolean result = compute(valueDouble);
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return result;
}
};
} else {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcDouble.call());
}
};
}
case STRING:
final Callable<String> funcString = evaluator.getStringFunction();
final String valueString = evaluator.isConstant() ? funcString.call() : null;
if (evaluator.isConstant()) {
final Boolean result = compute(valueString);
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return result;
}
};
} else {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcString.call());
}
};
}
case DATE:
final Callable<Date> funcDate = evaluator.getDateFunction();
final Date valueDate = evaluator.isConstant() ? funcDate.call() : null;
if (evaluator.isConstant()) {
final Boolean result = compute(valueDate);
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return result;
}
};
} else {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcDate.call());
}
};
}
case BOOLEAN:
final Callable<Boolean> funcBoolean = evaluator.getBooleanFunction();
final Boolean valueBoolean = evaluator.isConstant() ? funcBoolean.call() : null;
if (evaluator.isConstant()) {
final Boolean result = compute(valueBoolean);
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return result;
}
};
} else {
return new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
return compute(funcBoolean.call());
}
};
}
default:
return null;
}
} catch (ExpressionParsingException e) {
throw e;
} catch (Exception e) {
throw new ExpressionParsingException(e);
}
}
@Override
protected ExpressionType computeType(ExpressionType... inputTypes) {
// has to be one argument
if (inputTypes.length != 1) {
throw new FunctionInputException("expression_parser.function_wrong_input", getFunctionName(), "1",
inputTypes.length);
}
// result is always boolean
return ExpressionType.BOOLEAN;
}
/**
* Computes the result for a double value.
*
* @param value
* @return the result of the computation.
*/
protected Boolean compute(double value) {
if (Double.isNaN(value)) {
return true;
} else {
return false;
}
}
/**
* Computes the result for a boolean value.
*
* @param value
* @return the result of the computation.
*/
protected Boolean compute(Boolean value) {
if (value == null) {
return true;
} else {
return false;
}
}
/**
* Computes the result for a String value.
*
* @param value
* @return the result of the computation.
*/
protected Boolean compute(String value) {
if (value == null) {
return true;
} else {
return false;
}
}
/**
* Computes the result for a Date value.
*
* @param value
* @return the result of the computation.
*/
protected Boolean compute(Date value) {
if (value == null) {
return true;
} else {
return false;
}
}
}