Interface WeakHashClock<K,V>
- All Known Implementing Classes:
WeakHashClockImpl
public interface WeakHashClock<K,V>
This is a clock (if non-empty the next verb will always return a new value
in a cycle) that can also get values in O(1) complexity. This HashClock
also has Weak key references, so if the key becomes unavailable it
will not be retrievable from the get operation and the next operation
will remove it from the clock
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Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
Sets the clock size back to zero, no entriesvoid
Causes stale references to be cleared from the data structures.Gets the given key, returning null if not foundboolean
Tells if this WeakHashClock has Weak keysnext()
Returns the next key/value pair in the clock, or null if the clock has no members.void
Adds the given pair to the clock.void
releaseMatching
(CacheKeyFilter<K> filter) Releases all key/value pairs that match the filterRemoves the given key from the clock, if foundint
size()
Returns the number of elements currently in the clock.
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Method Details
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put
Adds the given pair to the clock. It will be placed at the current tail of the clock- Parameters:
key
- Must not be nullvalue
- May not be null
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get
Gets the given key, returning null if not found- Parameters:
key
- The key to search for, may not be null- Returns:
- The value found, or null if not found
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remove
Removes the given key from the clock, if found- Parameters:
key
- The key to remove, may not be null- Returns:
- The value removed if found, or null if not found
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releaseMatching
Releases all key/value pairs that match the filter- Parameters:
filter
- A non-null filter that can be used to delete every key/value pair that matches the filter
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size
int size()Returns the number of elements currently in the clock. References that have gone away because they were weakly referenced will not be counted in the size- Returns:
- The number of entries currently in the clock
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next
Returns the next key/value pair in the clock, or null if the clock has no members. This will advance the head and tail of the clock to the next element. If the WeakReference for the returned element is null then this element will also have been removed from the clock by this operation- Returns:
- The next key/value pair in the
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clear
void clear()Sets the clock size back to zero, no entries -
clearStaleReferences
void clearStaleReferences()Causes stale references to be cleared from the data structures. Since this is a weak clock the references can go away at any time, which happens whenever any operation has been performed. However, it may be the case that no operation will be performed for a while and so this method is provided to have a no-op operation to call in order to clear out any stale references -
hasWeakKeys
boolean hasWeakKeys()Tells if this WeakHashClock has Weak keys- Returns:
- true if this map has weak keys, true otherwise
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