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A Java library to parse, migrate and validate crons as well as describe them in human readable language

There is a newer version: 9.2.1

/*
 * Copyright 2014 jmrozanec
 * 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 com.cronutils.descriptor;

import java.util.HashSet;
import java.util.ResourceBundle;
import java.util.Set;

import com.cronutils.Function;
import com.cronutils.model.field.expression.FieldExpression;

import static com.cronutils.model.field.expression.FieldExpression.always;

/**
 * Description strategy where a cron field number can be mapped to a name.
 * Ex.: days of week or months
 */
class NominalDescriptionStrategy extends DescriptionStrategy {
    private FieldExpression expression;
    private final Set> descriptions;

    /**
     * Constructor.
     *
     * @param bundle               - locale in which description should be given
     * @param nominalValueFunction - function that maps Integer to String.
     *                             The function should return "" if does not match criteria,
     *                             or the description otherwise.
     * @param expression           - CronFieldExpression instance, the expression to be described.
     */
    public NominalDescriptionStrategy(final ResourceBundle bundle, final Function nominalValueFunction, final FieldExpression expression) {
        super(bundle);
        descriptions = new HashSet<>();
        if (nominalValueFunction != null) {
            this.nominalValueFunction = nominalValueFunction;
        }
        if (expression != null) {
            this.expression = expression;
        } else {
            this.expression = always();
        }
    }

    @Override
    public String describe() {
        for (final Function function : descriptions) {
            if (!"".equals(function.apply(expression))) {
                return function.apply(expression);
            }
        }
        return describe(expression);
    }

    /**
     * Allows to provide a specific description to handle a CronFieldExpression instance.
     *
     * @param desc - function that maps CronFieldExpression to String.
     *             The function should return "" if does not match criteria,
     *             or the description otherwise.
     * @return NominalDescriptionStrategy, this instance
     */
    public NominalDescriptionStrategy addDescription(final Function desc) {
        descriptions.add(desc);
        return this;
    }
}