RandomSec/main/src/com/google/refine/expr/functions/strings/Diff.java

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package com.google.refine.expr.functions.strings;

import java.util.Calendar;
import java.util.Date;
import java.util.Properties;

import org.apache.commons.lang.StringUtils;
import org.json.JSONException;
import org.json.JSONWriter;

import com.google.refine.expr.EvalError;
import com.google.refine.expr.util.CalendarParser;
import com.google.refine.expr.util.CalendarParserException;
import com.google.refine.grel.Function;

public class Diff implements Function {

    @Override
    public Object call(Properties bindings, Object[] args) {
        if (args.length >= 2) {
            Object o1 = args[0];
            Object o2 = args[1];
            if (o1 != null && o2 != null) {
                if (args.length == 2 && o1 instanceof String && o2 instanceof String) {
                    return StringUtils.difference((String) o1,(String) o2);
                } else if ((o1 instanceof Date || o1 instanceof Calendar) && args.length == 3) {
                    Object o3 = args[2];
                    if (o3 != null && o3 instanceof String) {
                        try {
                            String unit = ((String) o3).toLowerCase();
                            Date c1 = (o1 instanceof Date) ? (Date) o1 : ((Calendar) o1).getTime();
                            Date c2;
                            if (o2 instanceof Date) {
                                c2 = (Date) o2;
                            } else if (o2 instanceof Calendar) {
                                c2 = ((Calendar) o2).getTime();
                            } else {
                                c2 = CalendarParser.parse((o2 instanceof String) ? (String) o2 : o2.toString()).getTime();
                            }
                            long delta = (c1.getTime() - c2.getTime()) / 1000;
                            if ("seconds".equals(unit)) {
                                return delta;
                            }
                            delta /= 60;
                            if ("minutes".equals(unit)) {
                                return delta;
                            }
                            delta /= 60;
                            if ("hours".equals(unit)) {
                                return delta;
                            }
                            long days = delta / 24;
                            if ("days".equals(unit)) {
                                return days;
                            }
                            if ("weeks".equals(unit)) {
                                return days / 7;
                            }
                            if ("months".equals(unit)) {
                                return days / 30;
                            }
                            if ("years".equals(unit)) {
                                return days / 365;
                            }
                            return new EvalError("Unknown time unit " + unit);
                        } catch (CalendarParserException e) {
                            return new EvalError(e);
                        }
                    }
                }
            }
        }
        return new EvalError("Unexpected arguments - expecting either 2 strings or 2 dates and a unit string");
    }
    
    @Override
    public void write(JSONWriter writer, Properties options) throws JSONException {
        writer.object();
        writer.key("description"); writer.value("For strings, returns the portion where they differ. For dates, it returns the difference in given time units");
        writer.key("params"); writer.value("o1, o2, time unit (optional)");
        writer.key("returns"); writer.value("string for strings, number for dates");
        writer.endObject();
    }
}