ru.histone.evaluator.functions.global.Max Maven / Gradle / Ivy

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/**
 *    Copyright 2013 MegaFon
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package ru.histone.evaluator.functions.global;

import ru.histone.evaluator.nodes.Node;
import ru.histone.evaluator.nodes.NodeFactory;
import ru.histone.evaluator.nodes.NumberHistoneNode;
import ru.histone.evaluator.nodes.ObjectHistoneNode;
import ru.histone.utils.ArrayUtils;

import java.util.Map;

/**
 * Return maximum value from specified arguments

 * When calculating max value, all arguments are casted to number type
 */
public class Max extends GlobalFunction {
    public Max(NodeFactory nodeFactory) {
        super(nodeFactory);
    }

    @Override
    public String getName() {
        return "max";
    }

    @Override
    public Node execute(Node... args) {
        if (ArrayUtils.isEmpty(args)) {
            return getNodeFactory().UNDEFINED;
        }
        NumberHistoneNode result = null;
        for (Node arg : args) {
			if (arg.isNumber()) {
				NumberHistoneNode argNum = (NumberHistoneNode) arg;
				result = (result == null || result.compareTo(argNum) < 0) ? argNum : result;
			} else if (arg.isObject()) {
				result = findMax(result, (ObjectHistoneNode) arg);
			}
        }
        return result == null ? getNodeFactory().UNDEFINED : result;
    }
    
	private NumberHistoneNode findMax(NumberHistoneNode previous, ObjectHistoneNode values) {
		NumberHistoneNode result = previous;
		Map map = values.getElements();
		for (Node valueNode : map.values()) {
			if (valueNode.isNumber()) {
				NumberHistoneNode numberNode = (NumberHistoneNode) valueNode;
				result = (result == null || result.compareTo(numberNode) < 0) ? numberNode : result;
			} else if (valueNode.isObject()) {
				result = findMax(result, (ObjectHistoneNode) valueNode);
			}
		}
		return result == null ? previous : result;
	}

}