com.jidesoft.grouper.date
Class DateGrouper

java.lang.Object
  com.jidesoft.grouper.AbstractObjectGrouper
      com.jidesoft.grouper.date.DateGrouper

All Implemented Interfaces:

ObjectGrouper

Direct Known Subclasses:

DateDayOfMonthGrouper, DateDayOfWeekGrouper, DateDayOfWeekInMonthGrouper, DateDayOfYearGrouper, DateMonthGrouper, DateQuarterGrouper, DateWeekOfMonthGrouper, DateWeekOfYearGrouper, DateYearGrouper

public abstract class DateGrouper
extends AbstractObjectGrouper

An abstract Grouper which can take data type such as Date, Calendar or Long and provide getCalendarFieldAsInt(Object, int) and getCalendarField(Object, int) methods to access the field of the Calendar.

Field Summary

protected static Calendar

INSTANCE

Constructor Summary

DateGrouper()

Method Summary

static Object	getCalendarField(Object value, int field) Gets the field value from the value.
static int	getCalendarFieldAsInt(Object value, int field) Gets the field value from the value.
static Calendar	getCalendarInstance() To avoid creating too many instance of Calendar and improve the performance, getCalendarField(Object, int) and getCalendarFieldAsInt(Object, int) will use a cached instance of Calendar if the value passed in is Date or Long.
Class<?>	getType() Gets the group value type.

Methods inherited from class com.jidesoft.grouper.AbstractObjectGrouper

getComparatorContext, getConverterContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.jidesoft.grouper.ObjectGrouper

getName, getValue

Field Detail

INSTANCE

protected static Calendar INSTANCE

Constructor Detail

DateGrouper

public DateGrouper()

Method Detail

getCalendarInstance

public static Calendar getCalendarInstance()

To avoid creating too many instance of Calendar and improve the performance, getCalendarField(Object, int) and getCalendarFieldAsInt(Object, int) will use a cached instance of Calendar if the value passed in is Date or Long. By default, the cached Calendar instance was created from Calendar.getInstance(). This method will give you this instance and allow you to modify it. For example, setting a different time-zone. Since this instance is static, there is only one instance for the whole application. So just so you know, if you modify it, it will affect all the usages.

Returns:

the Calendar instance used by the two getCalendarField methods.

getCalendarField

public static Object getCalendarField(Object value,
                                      int field)

Gets the field value from the value.

Parameters:

value - a Date, Long or Calendar. If the value is a Date or a Long, we will use a cached Calendar instance to get the field value. This cached Calendar instance can be retrieved using getCalendarInstance() in case you want to customize it.

field - the field as defined in Calendar such as Calender.YEAR, Calendar.DAY_OF_MONTH.

Returns:

the field value. Null if the value that was passed in is null.

Throws:

IllegalArgumentException - if the value is not a Date, a Long or a Calendar.

getCalendarFieldAsInt

public static int getCalendarFieldAsInt(Object value,
                                        int field)

Gets the field value from the value.

Parameters:

value - a Date, Long or Calendar. If the value is a Date or a Long, we will use a cached Calendar instance to get the field value. This cached Calendar instance can be retrieved using getCalendarInstance() in case you want to customize it.

field - the field as defined in Calendar such as Calender.YEAR, Calendar.DAY_OF_MONTH.

Returns:

the field value. -1 if the value that was passed in is null.

Throws:

IllegalArgumentException - if the value is not a Date, a Long or a Calendar.

getType

public Class<?> getType()

Description copied from interface: ObjectGrouper

Gets the group value type. It should be the type of the value that is returned from the getGroupValue.

Returns:

the group value type.