sos.dated.util
Class AbstractDatedObject

java.lang.Object
  |
  +--sos.dated.util.AbstractDatedObject

All Implemented Interfaces:

DatedObject

Direct Known Subclasses:

AbstractDatedCollection, AbstractDatedMap, AbstractDatedValue

public abstract class AbstractDatedObject

extends java.lang.Object

implements DatedObject

A partial implementation of a dated object. This class makes it easier to define a class that implements the DatedObject interface. This abstract class provides generic implementations of equals, hashCode, toString, and dateIterator(). Subclasses must define dateIterator(Date) and toString(Date).

Since:

1.0

See Also:

DatedObject

Field Summary

Fields inherited from interface sos.dated.util.DatedObject

MAX_DATE, MIN_DATE

Constructor Summary

protected

AbstractDatedObject() No-argument constructor available only to subclasses.

Method Summary

DateIterator	dateIterator() Returns an iterator of the date ranges of when this dated object has changed.
abstract DateIterator	dateIterator(java.util.Date date) Returns an iterator of the date ranges of when this dated object has changed, starting at the range that contains the specified date.
boolean	equals(java.util.Date date, DatedObject obj, java.util.Date objDate) Indicates if another dated object is equal to this dated object at specified dates.
boolean	equals(java.lang.Object obj) Indicates if this dated object is equivalent to the specified object.
int	hashCode() Returns the hash code value of this dated object.
int	hashCode(java.util.Date date) Returns a hash code value of this dated object at the specified date.
java.lang.String	toString() Returns a string representation of this dated object.
abstract java.lang.String	toString(java.util.Date date) Returns a string representation of this dated object at the specified date.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

AbstractDatedObject

protected AbstractDatedObject()

No-argument constructor available only to subclasses.

Method Detail

dateIterator

public DateIterator dateIterator()

Returns an iterator of the date ranges of when this dated object has changed. This method is equivalent to dateIterator( MIN_DATE ).

This implementation simply invokes dateIterator(Date), passing MIN_DATE.

Specified by:

dateIterator in interface DatedObject

Returns:

a date iterator positioned before the first date range

See Also:

dateIterator(Date)

dateIterator

public abstract DateIterator dateIterator(java.util.Date date)

Description copied from interface: DatedObject

Returns an iterator of the date ranges of when this dated object has changed, starting at the range that contains the specified date. Throughout a range returned by the iterator, the state of the dated object must be the same. Also, the states of the dated object must be different in two consecutive ranges returned by the iterator. There are no gaps in the ranges returned by the iterator. That is, if a previous date range exists, then a call to nextFrom returns the same date as previousTo. Passing MAX_DATE as the argument will return an iterator positioned at the end of the sequence.

Specified by:

dateIterator in interface DatedObject

Parameters:

date - date to position the iteration

Returns:

an iterator of the dates of when this dated object has changed, positioned immediately before the date range that contains the specified date

equals

public boolean equals(java.lang.Object obj)

Indicates if this dated object is equivalent to the specified object.

If the parameter is not a DatedObject, this implementation returns false. Otherwise, it returns true if the dates of these objects are equivalent and if these objects are equivalent at the dates.

Specified by:

equals in interface DatedObject

Overrides:

equals in class java.lang.Object

Parameters:

obj - object to check for equality to this dated object

Returns:

true if this dated object is deemed equivalent to the specified object

See Also:

equals(Date,DatedObject,Date)

equals

public boolean equals(java.util.Date date,
                      DatedObject obj,
                      java.util.Date objDate)

Indicates if another dated object is equal to this dated object at specified dates.

This implementation uses object identity to determine equality. In other words, it returns true if

   this == obj && date.equals( objDate )

Subclasses should override this method to impose a weaker equality condition.

Specified by:

equals in interface DatedObject

Parameters:

date - date at which this object should be tested

obj - the other dated object to be compared to

objDate - the date of the other dated object

Returns:

true if thid dated object at date date equals another dated object at date objDate

Throws:

java.lang.NullPointerException - if any of the parameters equal null

hashCode

public int hashCode()

Returns the hash code value of this dated object.

This implementation sums the bitwise exclusive or of the date and the object's hash code value at the date, for each date the object changes. Specifically (in pseudocode):

 hashCode = 0;
 for each date d that a change in the object occurs
    hashCode += d.hashCode() ^ hashCode( d )
 

Specified by:

hashCode in interface DatedObject

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code value of this dated object

See Also:

hashCode(Date)

hashCode

public int hashCode(java.util.Date date)

Returns a hash code value of this dated object at the specified date.

This implementation returns the identity hash code value of this dated object.

Specified by:

hashCode in interface DatedObject

Parameters:

date - date to which the value should correspond

Returns:

the hash code value of this dated object at the specified date

Throws:

java.lang.NullPointerException - if date is null

toString

public java.lang.String toString()

Returns a string representation of this dated object.

This implemention forms a string as follows. Start with an open angled bracket "<". For each date of this dated object, append "d:x, " where d is a change date and x is the result of calling toString( d ). After the last date change, do not append the comma, but add a closing angle bracket ">".

Overrides:

toString in class java.lang.Object

Returns:

a string representation of this dated object

toString

public abstract java.lang.String toString(java.util.Date date)

Description copied from interface: DatedObject

Returns a string representation of this dated object at the specified date.

Specified by:

toString in interface DatedObject

Parameters:

date - to which the string should correspond

Returns:

a string representation of this dated object