com.google.code.rptm.mailarchive.YearMonth.java Source code

Introduction

Here is the source code for com.google.code.rptm.mailarchive.YearMonth.java

Source

/*
 * Copyright 2010 Andreas Veithen
 *
 * 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.google.code.rptm.mailarchive;

import java.util.Calendar;
import java.util.GregorianCalendar;

import org.apache.commons.lang.StringUtils;

/**
 * Identifies a year and month.
 */
public class YearMonth {
    private final int year;
    private final int month;

    /**
     * Construct a new instance with the given year and month.
     * 
     * @param year the year
     * @param month the month
     */
    public YearMonth(int year, int month) {
        this.year = year;
        this.month = month;
    }

    /**
     * Construct a new instance with the year and month given by the current data.
     */
    public YearMonth() {
        GregorianCalendar cal = new GregorianCalendar();
        year = cal.get(Calendar.YEAR);
        month = cal.get(Calendar.MONTH) + 1;
    }

    /**
     * Get the year.
     * 
     * @return the year
     */
    public int getYear() {
        return year;
    }

    /**
     * Get the month.
     * 
     * @return a value in the range 1..12
     */
    public int getMonth() {
        return month;
    }

    /**
     * Construct a new instance representing the previous month.
     * 
     * @return the previous month
     */
    public YearMonth previous() {
        return month == 1 ? new YearMonth(year - 1, 12) : new YearMonth(year, month - 1);
    }

    /**
     * Construct a new instance representing the next month.
     * 
     * @return the next month
     */
    public YearMonth next() {
        return month == 12 ? new YearMonth(year + 1, 1) : new YearMonth(year, month + 1);
    }

    /**
     * Format the year and month as YYYYMM.
     * 
     * @return the formatted year and month
     */
    public String toSimpleFormat() {
        return year + StringUtils.leftPad(String.valueOf(month), 2, '0');
    }

    @Override
    public int hashCode() {
        return year * 31 + month;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        } else if (obj instanceof YearMonth) {
            YearMonth other = (YearMonth) obj;
            return year == other.year && month == other.month;
        } else {
            return false;
        }
    }
}