Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.date;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Objects;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import org.gvsig.timesupport.DataTypes;

import org.gvsig.timesupport.RelativeInstant;

import org.gvsig.timesupport.TimeSupportLocator;

import org.gvsig.tools.ToolsLocator;

import org.gvsig.tools.dataTypes.Coercion;

import org.gvsig.tools.dataTypes.CoercionException;

public class RelativeInstantFunction extends AbstractFunction {

    private final Coercion toInstant;

    public RelativeInstantFunction() {

        super("Date", "RelativeInstant",Range.is(1),

            "Returns a relative instant from the arguments",

            "RelativeInstant({{date}}, format)",

            new String[]{

                "date - a string with a date",

                "format - Optional. Format to use to parse the date"

            },

            "RelativeInstant",

            false

        );

        this.toInstant = ToolsLocator.getDataTypesManager().getCoercion(DataTypes.INSTANT);

    }

    @Override

    public boolean allowConstantFolding() {

        return true;

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) {

        if( args.length==1 ) {

            Object arg0 = getObject(args, 0);

            try {

                Object instant = this.toInstant.coerce(arg0);

                return instant;

            } catch (CoercionException ex) {

                throw new RuntimeException("Can't convert value '"+Objects.toString(arg0, "")+"' to instant.", ex);

            }

        }

        String format = getStr(args, 1);

        String date = getStr(args, 0);

        SimpleDateFormat df = new SimpleDateFormat();

        if( format != null ) {

            df.applyPattern(format);

        }

        try {

            Date x = df.parse(date);

            RelativeInstant instant = TimeSupportLocator.getManager().createRelativeInstant(x);

            return instant;

        } catch (ParseException ex) {

            throw new RuntimeException("Can't parse date value '"+date+"' with format '"+format==null?"":format+"'", ex);

        }

    }

}