org.xlrnet.tibaija.commands.math.UnaryCommand.java Source code

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Here is the source code for org.xlrnet.tibaija.commands.math.UnaryCommand.java

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/*
 * Copyright (c) 2015 Jakob Hende
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE
 */

package org.xlrnet.tibaija.commands.math;

import com.google.common.collect.ImmutableList;
import org.apache.commons.math3.complex.Complex;
import org.jetbrains.annotations.NotNull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xlrnet.tibaija.exception.IllegalTypeException;
import org.xlrnet.tibaija.memory.Parameter;
import org.xlrnet.tibaija.memory.Value;
import org.xlrnet.tibaija.memory.Variables;
import org.xlrnet.tibaija.processor.Command;
import org.xlrnet.tibaija.util.ValueUtils;

import java.util.List;
import java.util.Optional;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Generic implementation for arithmetic operations with one operand like (, , ! or "not(". Uses a functional enum
 * pattern
 * for instantiation.
 */
public class UnaryCommand extends Command {

    private static final Logger LOGGER = LoggerFactory.getLogger(BinaryCommand.class);

    /**
     * A function with one parameter that will be used to calculate the result of an operation
     */
    private final UnaryOperator<Value> evaluationFunction;

    private UnaryCommandOperator operator;

    public UnaryCommand(UnaryCommandOperator operator) {
        this(operator.getOperatorFunction());
        this.operator = operator;
    }

    protected UnaryCommand(UnaryOperator<Value> evaluationFunction) {
        this.evaluationFunction = evaluationFunction;
    }

    @NotNull
    @Override
    protected Optional<Value> execute(@NotNull ImmutableList<Parameter> arguments) {
        final Value operand = arguments.get(0).value();
        final Value result = applyOperator(operand);

        LOGGER.debug("({}) {} -> {}", operator, operand.getValue(), result.getValue());

        return Optional.of(result);
    }

    /**
     * Check if both arguments are of a numerical type and not null.
     *
     * @param arguments
     *         The arguments for the command.
     * @return True if both arguments are of a numerical type and not null.
     */
    @Override
    protected boolean hasValidArgumentValues(@NotNull ImmutableList<Parameter> arguments) {
        final Value operand = arguments.get(0).value();
        checkNotNull(operand);

        if (!ValueUtils.isNumberOrList(operand))
            throw new IllegalTypeException("Operand is not a Number: " + operand.getValue(),
                    Variables.VariableType.NUMBER, operand.getType());

        return true;
    }

    /**
     * Check if exactly one argument was passed.
     *
     * @param numberOfParametersEntered
     *         Number of parameters passed by the caller.
     * @return True if exactly two arguments were passed.
     */
    @Override
    protected boolean hasValidNumberOfArguments(int numberOfParametersEntered) {
        return numberOfParametersEntered == 1;
    }

    /**
     * Apply the internal operator function on the given operand. If the operand is a Number, the function will be
     * applied to the numerical value. If the operand is a list, the function will be applied to each number in the
     * list and return a new list. Any other value type will cause an exception.
     *
     * @param operand
     *         The value to which the function should be applied.
     * @return A new Value object with the internal function applied to it.
     */
    private Value applyOperator(Value operand) {
        Value result;
        if (operand.isList()) {
            List<Complex> valueList = operand.list().stream()
                    .map(c -> evaluationFunction.apply(Value.of(c)).complex()).collect(Collectors.toList());
            result = Value.of(valueList);
        } else {
            result = evaluationFunction.apply(operand);
        }
        return result;
    }

}