Class CacheLIRS<K,V>
- java.lang.Object
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- org.apache.jackrabbit.oak.cache.CacheLIRS<K,V>
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- Type Parameters:
K
- the key typeV
- the value type
- All Implemented Interfaces:
java.util.function.Function<K,V>
,org.apache.jackrabbit.guava.common.base.Function<K,V>
,org.apache.jackrabbit.guava.common.cache.Cache<K,V>
,org.apache.jackrabbit.guava.common.cache.LoadingCache<K,V>
@Internal(since="1.1.1") @Deprecated(since="2022-12-01") public class CacheLIRS<K,V> extends java.lang.Object implements org.apache.jackrabbit.guava.common.cache.LoadingCache<K,V>
Deprecated.The Jackrabbit Oak Cache library is designed for Oak-internal use only and thus deprecated. It will not be part of the AEM SDK after April 2023.For Oak internal use only. Do not use outside Oak components.A scan resistant cache. It is meant to cache objects that are relatively costly to acquire, for example file content.
This implementation is multi-threading safe and supports concurrent access. Null keys or null values are not allowed. The map fill factor is at most 75%.
Each entry is assigned a distinct memory size, and the cache will try to use at most the specified amount of memory. The memory unit is not relevant, however it is suggested to use bytes as the unit.
This class implements an approximation of the the LIRS replacement algorithm invented by Xiaodong Zhang and Song Jiang as described in http://www.cse.ohio-state.edu/~zhang/lirs-sigmetrics-02.html with a few smaller changes: An additional queue for non-resident entries is used, to prevent unbound memory usage. The maximum size of this queue is at most the size of the rest of the stack. About 6.25% of the mapped entries are cold.
Internally, the cache is split into a number of segments, and each segment is an individual LIRS cache.
Accessed entries are only moved to the top of the stack if at least a number of other entries have been moved to the front (1% by default). Write access and moving entries to the top of the stack is synchronized per segment.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
CacheLIRS.Builder<K,V>
Deprecated.The Jackrabbit Oak Cache library is designed for Oak-internal use only and thus deprecated.static interface
CacheLIRS.EvictionCallback<K,V>
Deprecated.The Jackrabbit Oak Cache library is designed for Oak-internal use only and thus deprecated.
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Constructor Summary
Constructors Constructor Description CacheLIRS(int maxEntries)
Deprecated.Create a new cache with the given number of entries, and the default settings (an average size of 1 per entry, 16 segments, and stack move distance equals to the maximum number of entries divided by 100).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description V
apply(K key)
Deprecated.java.util.concurrent.ConcurrentMap<K,V>
asMap()
Deprecated.void
cleanUp()
Deprecated.boolean
containsKey(java.lang.Object key)
Deprecated.Check whether there is a resident entry for the given key.java.util.Set<java.util.Map.Entry<K,V>>
entrySet()
Deprecated.Get the entry set for all resident entries.V
get(K key)
Deprecated.Get the value, loading it if needed.V
get(K key, java.util.concurrent.Callable<? extends V> valueLoader)
Deprecated.org.apache.jackrabbit.guava.common.collect.ImmutableMap<K,V>
getAll(java.lang.Iterable<? extends K> keys)
Deprecated.org.apache.jackrabbit.guava.common.collect.ImmutableMap<K,V>
getAllPresent(java.lang.Iterable<?> keys)
Deprecated.int
getAverageMemory()
Deprecated.Get the average memory used per entry.V
getIfPresent(java.lang.Object key)
Deprecated.Get the value for the given key if the entry is cached.long
getMaxMemory()
Deprecated.Get the maximum memory to use.int
getMemory(K key)
Deprecated.Get the memory used for the given key.V
getUnchecked(K key)
Deprecated.Get the value, loading it if needed.long
getUsedMemory()
Deprecated.Get the currently used memory.void
invalidate(java.lang.Object key)
Deprecated.Remove an entry.void
invalidateAll()
Deprecated.Remove all entries.void
invalidateAll(java.lang.Iterable<?> keys)
Deprecated.boolean
isEmpty()
Deprecated.java.util.List<K>
keys(boolean cold, boolean nonResident)
Deprecated.Get the list of keys.java.util.Set<K>
keySet()
Deprecated.Get the set of keys for resident entries.static <K,V>
CacheLIRS.Builder<K,V>newBuilder()
Deprecated.Create a builder.V
peek(K key)
Deprecated.Get the value for the given key if the entry is cached.void
put(K key, V value)
Deprecated.Add an entry to the cache.V
put(K key, V value, int memory)
Deprecated.Add an entry to the cache.void
putAll(java.util.Map<? extends K,? extends V> m)
Deprecated.void
refresh(K key)
Deprecated.Re-load the value for the given key.V
remove(java.lang.Object key)
Deprecated.Remove an entry.void
setAverageMemory(int averageMemory)
Deprecated.Set the average memory used per entry.void
setMaxMemory(long maxMemory)
Deprecated.Set the maximum memory this cache should use.long
size()
Deprecated.Get the number of resident entries.int
sizeHot()
Deprecated.Get the number of hot entries in the cache.int
sizeMapArray()
Deprecated.Get the length of the internal map array.int
sizeNonResident()
Deprecated.Get the number of non-resident entries in the cache.org.apache.jackrabbit.guava.common.cache.CacheStats
stats()
Deprecated.
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Constructor Detail
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CacheLIRS
public CacheLIRS(int maxEntries)
Deprecated.Create a new cache with the given number of entries, and the default settings (an average size of 1 per entry, 16 segments, and stack move distance equals to the maximum number of entries divided by 100).- Parameters:
maxEntries
- the maximum number of entries
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Method Detail
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invalidateAll
public void invalidateAll()
Deprecated.Remove all entries.
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containsKey
public boolean containsKey(java.lang.Object key)
Deprecated.Check whether there is a resident entry for the given key. This method does not adjust the internal state of the cache.- Parameters:
key
- the key (may not be null)- Returns:
- true if there is a resident entry
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peek
public V peek(K key)
Deprecated.Get the value for the given key if the entry is cached. This method does not modify the internal state.- Parameters:
key
- the key (may not be null)- Returns:
- the value, or null if there is no resident entry
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put
public V put(K key, V value, int memory)
Deprecated.Add an entry to the cache. This method is an explicit memory size (weight), and not using the weigher even if configured. The entry may or may not exist in the cache yet. This method will usually mark unknown entries as cold and known entries as hot.- Parameters:
key
- the key (may not be null)value
- the value (may not be null)memory
- the memory used for the given entry- Returns:
- the old value, or null if there was no resident entry
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put
public void put(K key, V value)
Deprecated.Add an entry to the cache. If a weigher is specified, it is used, otherwise the average memory size is used.
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get
public V get(K key, java.util.concurrent.Callable<? extends V> valueLoader) throws java.util.concurrent.ExecutionException
Deprecated.
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getUnchecked
public V getUnchecked(K key)
Deprecated.Get the value, loading it if needed.If there is an exception loading, an UncheckedExecutionException is thrown.
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get
public V get(K key) throws java.util.concurrent.ExecutionException
Deprecated.Get the value, loading it if needed.
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refresh
public void refresh(K key)
Deprecated.Re-load the value for the given key.If there is an exception while loading, it is logged and ignored. This method calls CacheLoader.reload, but synchronously replaces the old value.
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getIfPresent
@Nullable public V getIfPresent(java.lang.Object key)
Deprecated.Get the value for the given key if the entry is cached. This method adjusts the internal state of the cache sometimes, to ensure commonly used entries stay in the cache.
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invalidate
public void invalidate(java.lang.Object key)
Deprecated.Remove an entry. Both resident and non-resident entries can be removed.
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remove
public V remove(java.lang.Object key)
Deprecated.Remove an entry. Both resident and non-resident entries can be removed.- Parameters:
key
- the key (may not be null)- Returns:
- the old value or null
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invalidateAll
public void invalidateAll(java.lang.Iterable<?> keys)
Deprecated.
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getMemory
public int getMemory(K key)
Deprecated.Get the memory used for the given key.- Parameters:
key
- the key (may not be null)- Returns:
- the memory, or 0 if there is no resident entry
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getUsedMemory
public long getUsedMemory()
Deprecated.Get the currently used memory.- Returns:
- the used memory
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setMaxMemory
public void setMaxMemory(long maxMemory)
Deprecated.Set the maximum memory this cache should use. This will not immediately cause entries to get removed however; it will only change the limit. To resize the internal array, call the clear method.- Parameters:
maxMemory
- the maximum size (1 or larger)
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setAverageMemory
public void setAverageMemory(int averageMemory)
Deprecated.Set the average memory used per entry. It is used to calculate the length of the internal array.- Parameters:
averageMemory
- the average memory used (1 or larger)
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getAverageMemory
public int getAverageMemory()
Deprecated.Get the average memory used per entry.- Returns:
- the average memory
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getMaxMemory
public long getMaxMemory()
Deprecated.Get the maximum memory to use.- Returns:
- the maximum memory
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entrySet
public java.util.Set<java.util.Map.Entry<K,V>> entrySet()
Deprecated.Get the entry set for all resident entries.- Returns:
- the entry set
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keySet
public java.util.Set<K> keySet()
Deprecated.Get the set of keys for resident entries.- Returns:
- the set of keys
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sizeNonResident
public int sizeNonResident()
Deprecated.Get the number of non-resident entries in the cache.- Returns:
- the number of non-resident entries
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sizeMapArray
public int sizeMapArray()
Deprecated.Get the length of the internal map array.- Returns:
- the size of the array
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sizeHot
public int sizeHot()
Deprecated.Get the number of hot entries in the cache.- Returns:
- the number of hot entries
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size
public long size()
Deprecated.Get the number of resident entries.
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keys
public java.util.List<K> keys(boolean cold, boolean nonResident)
Deprecated.Get the list of keys. This method allows to read the internal state of the cache.- Parameters:
cold
- if true, only keys for the cold entries are returnednonResident
- true for non-resident entries- Returns:
- the key list
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stats
public org.apache.jackrabbit.guava.common.cache.CacheStats stats()
Deprecated.
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newBuilder
public static <K,V> CacheLIRS.Builder<K,V> newBuilder()
Deprecated.Create a builder.- Returns:
- the builder
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getAllPresent
public org.apache.jackrabbit.guava.common.collect.ImmutableMap<K,V> getAllPresent(java.lang.Iterable<?> keys)
Deprecated.
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cleanUp
public void cleanUp()
Deprecated.
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getAll
public org.apache.jackrabbit.guava.common.collect.ImmutableMap<K,V> getAll(java.lang.Iterable<? extends K> keys) throws java.util.concurrent.ExecutionException
Deprecated.
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isEmpty
public boolean isEmpty()
Deprecated.
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