com.jdc.util
Class Refresh

java.lang.Object
  |
  +--com.jdc.util.Refresh

public final class Refresh

extends Object

Refresh represents a utility class that determines when a class containing data should be refreshed. A class containing data is usually, but is not required to be a singleton. It is recommended that a singleton class implement the Singleton interface.

This class may utilized in one of two ways. If the specified class implements the Singleton interface, you may check if a class refresh is required as in the following example:

        if (Refresh.isRequired(Singleton)))
        {
            // Perform refresh.
        } 

No additional code is required in the class implementing the Singleton interface. This class maintains the Refresh.Status for the specified class to enable it to determine when a refresh is required.

Note: It is the responsibility of the class developer to ensure that the specified class is properly implemented as a singleton. If it is not, this class may produce undesirable results.

Or, you may declare an instance of Refresh.Status in your class and, optionally, specify a refresh time and/or interval. If you choose to maintain your own refresh Timestamp (and you must for classes with multiple instances), you may check if a class refresh is required as in the following example:

        if (Refresh.isRequired(Refresh.Status)))
        {
            // Perform refresh.
        } 

Note: You may specify a class refresh time and/or refresh interval when creating a new Refresh.Status instance using the Refresh.Status(Object, Refresh.Time, Refresh.Interval) constructor.

It is important to note that this class is an implementation of a lazy refresh, i.e. a refresh of a specified class instance will not occur until the class instance invokes one of the Refresh.isRequired methods and a result of true is returned. Therefore, it is likely that an invoking class instance will not be refreshed precisely at the requested refresh time and/or interval or, perhaps, not at all if the invoking class is never instantiated.

Version:

1.0

Author:

J. Damon & Co.

See Also:

Refresh.Status, Singleton

Nested Class Summary

protected class	Refresh.Interval Interval represents an interval or the amount of time between refreshes of a specified class instance.
class	Refresh.Status Status represents a Timestamp denoting the last refresh time for a specified class instance.
protected class	Refresh.Time Time represents the time of day a refresh of a specified class instance should occur.
protected class	Refresh.Timestamp Interval represents an interval or the amount of time between refreshes of a specified class instance.

Method Summary

static void	all() Initializes the last refresh time for all registered classes in order to force a refresh on the next class access.
static void	initialize(String className) Initializes the last refresh time for the specified singleton class instance given a fully-qualified class name in order to force a refresh on the next class access.
static boolean	isRequired(Object object) Returns true if a refresh is required for the specified Object class instance.
static boolean	isRequired(Refresh.Status lastRefresh) Returns true if a refresh is required given the last Refresh.Status.
static Iterator	iterator() Returns an Iterator for all registered refresh class instances.

Methods inherited from class java.lang.Object

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

Method Detail

all

public static void all()

Initializes the last refresh time for all registered classes in order to force a refresh on the next class access.

initialize

public static void initialize(String className)

Initializes the last refresh time for the specified singleton class instance given a fully-qualified class name in order to force a refresh on the next class access.

isRequired

public static boolean isRequired(Refresh.Status lastRefresh)

Returns true if a refresh is required given the last Refresh.Status.

Returns:

True if a refresh is required.
False if a refresh is not required.

isRequired

public static boolean isRequired(Object object)

Returns true if a refresh is required for the specified Object class instance.

Returns:

True if a refresh is required.
False if a refresh is not required.

iterator

public static Iterator iterator()

Returns an Iterator for all registered refresh class instances.

Returns:

An Iterator for all registered refresh class instances.