io.warp10.script.functions.ADDMONTHS.java Source code

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Here is the source code for io.warp10.script.functions.ADDMONTHS.java

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//
//   Copyright 2016  Cityzen Data
//
//   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 io.warp10.script.functions;

import java.util.ArrayList;
import java.util.List;

import io.warp10.continuum.store.Constants;
import io.warp10.script.NamedWarpScriptFunction;
import io.warp10.script.WarpScriptException;
import io.warp10.script.WarpScriptStack;
import io.warp10.script.WarpScriptStackFunction;

import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;

/**
 * Adds a month to a timestamp
 */
public class ADDMONTHS extends NamedWarpScriptFunction implements WarpScriptStackFunction {

    public ADDMONTHS(String name) {
        super(name);
    }

    @Override
    public Object apply(WarpScriptStack stack) throws WarpScriptException {

        Object top = stack.pop();

        if (!(top instanceof Long)) {
            throw new WarpScriptException(getName() + " expects a number of months on top of the stack.");
        }

        int months = ((Number) top).intValue();

        top = stack.pop();

        String tz = null;

        if (top instanceof String) {
            tz = top.toString();
            top = stack.pop();
            if (!(top instanceof Long)) {
                throw new WarpScriptException(
                        getName() + " operates on a tselements list, timestamp, or timestamp and timezone.");
            }
        } else if (!(top instanceof List) && !(top instanceof Long)) {
            throw new WarpScriptException(
                    getName() + " operates on a tselements list, timestamp, or timestamp and timezone.");
        }

        if (top instanceof Long) {
            long instant = ((Number) top).longValue();

            if (null == tz) {
                tz = "UTC";
            }

            DateTimeZone dtz = DateTimeZone.forID(null == tz ? "UTC" : tz);

            DateTime dt = new DateTime(instant / Constants.TIME_UNITS_PER_MS, dtz);

            dt = dt.plusMonths(months);

            long ts = dt.getMillis() * Constants.TIME_UNITS_PER_MS + (instant % Constants.TIME_UNITS_PER_MS);

            stack.push(ts);
        } else {
            List<Object> elts = new ArrayList<Object>((List<Object>) top);

            int year = ((Number) elts.get(0)).intValue();
            int month = ((Number) elts.get(1)).intValue();

            if (months < 0) {
                while (months < 0) {
                    months++;
                    month = month - 1;
                    if (month < 1) {
                        month = 12;
                        year--;
                    }
                }
            } else {
                while (months > 0) {
                    months--;
                    month = month + 1;
                    if (month > 12) {
                        month = 1;
                        year++;
                    }
                }
            }

            elts.set(0, (long) year);
            elts.set(1, (long) month);

            // Now check that the month is compatible with the day

            if (elts.size() > 2) {
                int day = ((Number) elts.get(2)).intValue();

                if (2 == month && day > 28) {
                    if ((0 != year % 4) || (0 == year % 100)) {
                        elts.set(2, (long) 28);
                    } else {
                        elts.set(2, (long) 29);
                    }
                } else if (day > 30 && (4 == month || 6 == month || 9 == month || 11 == month)) {
                    elts.set(2, (long) 30);
                }
            }

            stack.push(elts);
        }

        return stack;
    }
}