org.hisp.dhis.rules.functions.RuleFunctionMonthsBetween Maven / Gradle / Ivy

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package org.hisp.dhis.rules.functions;

/*
 * Copyright (c) 2004-2018, University of Oslo
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * Neither the name of the HISP project nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import org.hisp.dhis.parser.expression.antlr.ExpressionParser.ExprContext;
import org.hisp.dhis.rules.models.TimeInterval;
import org.hisp.dhis.rules.parser.expression.CommonExpressionVisitor;
import org.hisp.dhis.rules.parser.expression.function.ScalarFunctionToEvaluate;
import org.joda.time.Months;

import static org.hisp.dhis.antlr.AntlrParserUtils.castDate;

/**
 * @author Zubair Asghar.
 */

public class RuleFunctionMonthsBetween
    extends ScalarFunctionToEvaluate
{
    public static RuleFunctionMonthsBetween create()
    {
        return new RuleFunctionMonthsBetween();
    }

    /**
     * Function which will return the number of months between the two given dates.
     *
     * @param start the start date.
     * @param end   the end date.
     * @return number of months between dates.
     */
    private Integer monthsBetween( String start, String end )
    {
        TimeInterval interval = RuleFunction.getTimeInterval( start, end );

        if ( interval.isEmpty() )
        {
            return 0;
        }

        return Months.monthsBetween( interval.getStartDate(), interval.getEndDate() ).getMonths();
    }

    @Override
    public Object evaluate( ExprContext ctx, CommonExpressionVisitor visitor )
    {
        return String.valueOf(
            monthsBetween( visitor.castStringVisit( ctx.expr( 0 ) ),
                visitor.castStringVisit( ctx.expr( 1 ) ) ) );
    }

    @Override
    public Object getDescription( ExprContext ctx, CommonExpressionVisitor visitor )
    {
        castDate( visitor.visit( ctx.expr( 0 ) ) );
        castDate( visitor.visit( ctx.expr( 1 ) ) );

        return CommonExpressionVisitor.DEFAULT_DOUBLE_VALUE;
    }
}