com.atlassian.crowd.util

Class BoundedCount

java.lang.Object

com.atlassian.crowd.util.BoundedCount

public class BoundedCount
extends Object

A possibly approximate count of the number of elements in a collection. The collection has at least getCount() elements. A count marked as exact has exactly count elements (see isExact(). This allows APIs to give indications of collection size without committing to expensive operations when an exact count requires significant work. Provided are some example scenarios and what the results mean:

(getCount(), isExact())

result

(5, true)

Count of elements is exactly 5

(5, false)

Count of elements is at least 5

(0, false)

Count of elements is zero or more (could be anything)

Method Summary

Modifier and Type	Method and Description
static BoundedCount	atLeast(long count) Create a BoundedCount that is at-least as big as a given number.
boolean	equals(Object o)
static BoundedCount	exactly(long count) Create a bounded count that exactly represents a number.
static BoundedCount	fromCountedItemsAndLimit(long count, long potentialMaxCount) Get a bounded count from counting up to an upper bound.
long	getCount() The number of elements counted in a collection.
int	hashCode()
boolean	isExact()
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

exactly

public static BoundedCount exactly(long count)

Create a bounded count that exactly represents a number.

Parameters:

count - The exact count that this represents; not a bounded number.

Returns:

A BoundedCount that is exact.

atLeast

public static BoundedCount atLeast(long count)

Create a BoundedCount that is at-least as big as a given number. This creates a lower bound on the provided count allowing you to indicate that the collection you are counting is bigger than a given count.

Parameters:

count - A number that is at-least as big as the real count of elements in a collection.

Returns:

A lower bounded count.

fromCountedItemsAndLimit

public static BoundedCount fromCountedItemsAndLimit(long count,
                                                    long potentialMaxCount)

Get a bounded count from counting up to an upper bound.

Parameters:

count - The number of elements that were actually counted.

potentialMaxCount - The maximum number of elements that we counted up to.

Returns:

Returns exactly the count given (if less than the upper bound) and returns at-least the upper bound otherwise.

getCount

public long getCount()

The number of elements counted in a collection.

Returns:

If isExact() returns true then it returns the exact size of the collection. Otherwise it returns a lower bound of the size of the collection. The answer will always be non-negative.

isExact

public boolean isExact()

Returns:

True if getCount() is known to be the exact number of elements in the collection. It will return False if this count represents a lower bound.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object