sos.dated.util
Class AbstractDatedObject<D>

java.lang.Object
  sos.dated.util.AbstractDatedObject<D>

Type Parameters:

D - the type of dates used by this dated object

All Implemented Interfaces:

DatedObject<D>

Direct Known Subclasses:

AbstractDatedCollection, AbstractDatedMap, AbstractDatedValue

public abstract class AbstractDatedObject<D>
extends java.lang.Object
implements DatedObject<D>

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

Constructor Summary

protected

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

Method Summary

DateIterator<D>	dateIterator() Returns an iterator of the date ranges of when this dated object has changed.
abstract DateIterator<D>	dateIterator(D at) 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(D at, DatedObject<D> obj, D objAt) Indicates if this dated object at at is equal to obj at objAt.
boolean	equals(java.lang.Object obj) Indicates if this dated object equals the specified object.
int	hashCode() Returns the hash code value of this dated object.
int	hashCode(D at) 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(D at) 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<D> dateIterator()

Returns an iterator of the date ranges of when this dated object has changed. This method is equivalent to dateIterator( null ). This implementation simply invokes dateIterator(D), passing null.

Specified by:

dateIterator in interface DatedObject<D>

Returns:

a date iterator positioned before the first date range

See Also:

DatedObject.dateIterator(Object)

dateIterator

public abstract DateIterator<D> dateIterator(D at)

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 null as the argument will return an iterator positioned at the beginning of the sequence.

Specified by:

dateIterator in interface DatedObject<D>

Parameters:

at - 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 equals the specified object. Two DatedObjects are equal if they have the same dates and if they are equal at each of these dates, as seen by equals(D,DatedObject,D). 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<D>

Overrides:

equals in class java.lang.Object

Parameters:

obj - object to compare this dated object to

Returns:

true if this dated object equals the specified object

See Also:

DatedObject.equals(Object,DatedObject,Object)

equals

public boolean equals(D at,
                      DatedObject<D> obj,
                      D objAt)

Indicates if this dated object at at is equal to obj at objAt. 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<D>

Parameters:

at - date at which this object should be tested

obj - the other dated object to be compared to

objAt - the date of the other dated object

Returns:

true if this dated object at at equals another dated object at objAt

Throws:

java.lang.NullPointerException - if any argument is 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<D>

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code value of this dated object

hashCode

public int hashCode(D at)

Returns a hash code value of this dated object at the specified date. For two dated objects o1 and o2 and two dates d1 and d2, if o1.equals( d1, o2, d2 ) returns true, then o1.hashCode( d1 ) must equal o2.hashCode( d2 ). This implementation returns the identity hash code value of this dated object.

Specified by:

hashCode in interface DatedObject<D>

Parameters:

at - date to which the hash code value should correspond

Returns:

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

Throws:

java.lang.NullPointerException - if at is null

toString

public java.lang.String toString()

Returns a string representation of this dated object. The string representation begins with the open angled bracket "<". Then, for each date of this dated object, "d:x, " appears, where d is a change date and x is the result of calling toString( d ). After the last date change, no comma appears, and the string representation is closed with 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(D at)

Description copied from interface: DatedObject

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

Specified by:

toString in interface DatedObject<D>

Parameters:

at - date to which the string should correspond

Returns:

a string representation of this dated object