PreparedQueryCacheImpl (OpenJPA Parent POM 3.2.1 API)

java.lang.Object
- org.apache.openjpa.jdbc.kernel.PreparedQueryCacheImpl

All Implemented Interfaces:

PreparedQueryCache, Configurable
```
public class PreparedQueryCacheImpl
extends Object
implements PreparedQueryCache
```
An implementation of the cache of prepared queries.

Since:

2.0.0

Author:

Pinaki Poddar

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`PreparedQueryCacheImpl.StrongExclusion` Strong exclusion.
`static class`	`PreparedQueryCacheImpl.WeakExclusion` Weak exclusion.

Nested classes/interfaces inherited from interface org.apache.openjpa.kernel.PreparedQueryCache
PreparedQueryCache.Exclusion

Constructor Summary

Constructors
Constructor and Description

PreparedQueryCacheImpl()

Constructors
Constructor and Description
`PreparedQueryCacheImpl()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addExclusionPattern(String pattern)` Adds a pattern for exclusion.
`boolean`	`cache(PreparedQuery q)` Cache the given query keyed by its identifier.
`void`	`clear()` Clears all cached queries.
`void`	`endConfiguration()` Invoked upon completion of bean property configuration for this object.
`PreparedQuery`	`get(String id)` Get the PreparedQuery with the given identifier if it exists. null otherwise.
`int`	`getCacheSize()`
`boolean`	`getEnableStatistics()` Affirm if statistics is gathered.
`List<PreparedQueryCache.Exclusion>`	`getExcludes()` Gets the exclusion patterns.
`Map<String,String>`	`getMapView()` Get a map view of the cached queries indexed by identifier.
`QueryStatistics<String>`	`getStatistics()` Gets the simple statistics for executed queries.
`PreparedQuery`	`initialize(String key, Object result)` Initialize the cached Prepared Query registered with the given key earlier by the given execution result.
`boolean`	`invalidate(String id)` Remove the PreparedQuery with the given identifier from this cache.
`Boolean`	`isCachable(String id)` Affirms if a PreparedQuery can be cached against the given key.
`PreparedQueryCache.Exclusion`	`isExcluded(String id)` Returns the exclusion status of if the given query key.
`protected void`	`lock(boolean readOnly)` Note: Care needs to be taken so that a read lock is never held while requesting a write lock.
`PreparedQuery`	`markUncachable(String id, PreparedQueryCache.Exclusion exclusion)` Marks the given key as not amenable to caching.
`Boolean`	`register(String id, Query query, FetchConfiguration hints)` Register the given query for caching against the given key if it has not already been cached.
`void`	`removeExclusionPattern(String pattern)` Removes a pattern for exclusion.
`void`	`setConfiguration(Configuration conf)` Invoked prior to setting bean properties.
`void`	`setEnableStatistics(boolean enable)` Enable/disable gathering of statistics.
`void`	`setExcludes(String excludes)` Sets one or more exclusion regular expression patterns separated by semicolon.
`void`	`setMaxCacheSize(int size)`
`void`	`startConfiguration()` Invoked before bean property configuration is begun on this object.
`protected void`	`unlock(boolean readOnly)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PreparedQueryCacheImpl
```
public PreparedQueryCacheImpl()
```
- Method Detail
  - register
```
public Boolean register(String id,
                        Query query,
                        FetchConfiguration hints)
```
    Description copied from interface: PreparedQueryCache
    
    Register the given query for caching against the given key if it has not already been cached. If the query can not be cached, then mark it as such to avoid computing for the same key again.
    
    Specified by:
    
    register in interface PreparedQueryCache
    
    Returns:
    
    TRUE the query is registered in the cache by this call null if the query is already registered in the cache FALSE if can not be registered in the cache, either because it is known not to be cacheable from a previous attempt or a hint is given to ignore the cached version.
  - getMapView
```
public Map<String,String> getMapView()
```
    Description copied from interface: PreparedQueryCache
    
    Get a map view of the cached queries indexed by identifier.
    
    Specified by:
    
    getMapView in interface PreparedQueryCache
  - cache
```
public boolean cache(PreparedQuery q)
```
    Cache the given query keyed by its identifier. Does not cache if the identifier matches any exclusion pattern or has been marked as non-cachable. Also register the identifier as not cachable against the matched exclusion pattern.
    
    Specified by:
    
    cache in interface PreparedQueryCache
    
    Returns:
    
    true if the given query is cached. false if it can not be cached due to exclusion.
    
    See Also:
    
    #markUncachable(String), PreparedQueryCache.setExcludes(String), PreparedQueryCache.addExclusionPattern(String)
  - initialize
```
public PreparedQuery initialize(String key,
                                Object result)
```
    Description copied from interface: PreparedQueryCache
    
    Initialize the cached Prepared Query registered with the given key earlier by the given execution result. If it is not possible to initialize the Prepared Query from the given execution result, then the corresponding key will be marked as invalid for caching.
    
    Specified by:
    
    initialize in interface PreparedQueryCache
    
    Parameters:
    
    key - the key used during registration
    
    result - an opaque instance carrying the execution result of the original query.
    
    Returns:
    
    the initialized Prepared Query. If it is not possible to initialize the cached, possibly hollow Prepared Query from the given result, return null.
  - invalidate
```
public boolean invalidate(String id)
```
    Description copied from interface: PreparedQueryCache
    
    Remove the PreparedQuery with the given identifier from this cache.
    
    Specified by:
    
    invalidate in interface PreparedQueryCache
  - get
```
public PreparedQuery get(String id)
```
    Description copied from interface: PreparedQueryCache
    
    Get the PreparedQuery with the given identifier if it exists. null otherwise.
    
    Specified by:
    
    get in interface PreparedQueryCache
  - isCachable
```
public Boolean isCachable(String id)
```
    Description copied from interface: PreparedQueryCache
    
    Affirms if a PreparedQuery can be cached against the given key.
    
    Specified by:
    
    isCachable in interface PreparedQueryCache
    
    Returns:
    
    Boolean.FALSE if the given key is explicitly marked before as not be cached or matches any of the exclusion patterns. Boolean.TRUE if the given key currently exists in the cache. Otherwise, return null implying this receiver can not determine whether this key can be cached on not.
  - markUncachable
```
public PreparedQuery markUncachable(String id,
                                    PreparedQueryCache.Exclusion exclusion)
```
    Description copied from interface: PreparedQueryCache
    
    Marks the given key as not amenable to caching. Explicit marking helps to avoid repeated computational cost of determining whether a query can be cached or not.
    
    Specified by:
    
    markUncachable in interface PreparedQueryCache
    
    Parameters:
    
    id - is the key to be excluded
    
    exclusion - directs whether exclusion is irreversible or not.
    
    Returns:
    
    The value for the given key if it had been cached before. null otherwise.
  - isExcluded
```
public PreparedQueryCache.Exclusion isExcluded(String id)
```
    Description copied from interface: PreparedQueryCache
    
    Returns the exclusion status of if the given query key.
    
    Specified by:
    
    isExcluded in interface PreparedQueryCache
    
    Returns:
    
    null implies that the key is not excluded.
  - setExcludes
```
public void setExcludes(String excludes)
```
    Description copied from interface: PreparedQueryCache
    
    Sets one or more exclusion regular expression patterns separated by semicolon. Any existing cache entry whose key matches any of the given pattern will be marked non-cachable in a reversible manner.
    
    Specified by:
    
    setExcludes in interface PreparedQueryCache
  - getExcludes
```
public List<PreparedQueryCache.Exclusion> getExcludes()
```
    Description copied from interface: PreparedQueryCache
    
    Gets the exclusion patterns.
    
    Specified by:
    
    getExcludes in interface PreparedQueryCache
  - addExclusionPattern
```
public void addExclusionPattern(String pattern)
```
    Adds a pattern for exclusion. Any query cached currently whose identifier matches the given pattern will be marked invalidated as a side-effect.
    
    Specified by:
    
    addExclusionPattern in interface PreparedQueryCache
  - removeExclusionPattern
```
public void removeExclusionPattern(String pattern)
```
    Removes a pattern for exclusion. Any query identifier marked as not cachable due to the given pattern will now be removed from the list of uncachables as a side-effect.
    
    Specified by:
    
    removeExclusionPattern in interface PreparedQueryCache
    
    See Also:
    
    PreparedQueryCache.markUncachable(String, Exclusion)
  - getStatistics
```
public QueryStatistics<String> getStatistics()
```
    Description copied from interface: PreparedQueryCache
    
    Gets the simple statistics for executed queries. If the statistics gathering is disabled, an empty statistics is returned.
    
    Specified by:
    
    getStatistics in interface PreparedQueryCache
  - lock
```
protected void lock(boolean readOnly)
```
    Note: Care needs to be taken so that a read lock is never held while requesting a write lock. This will result in a deadlock.
    
    Parameters:
    
    readOnly - - If true, a read lock will be acquired. Else a write lock will be acquired.
  - unlock
```
protected void unlock(boolean readOnly)
```
    Parameters:
    
    readOnly - - If true, the read lock will be released. Else a write lock will be released.
  - clear
```
public void clear()
```
    Description copied from interface: PreparedQueryCache
    
    Clears all cached queries.
    
    Specified by:
    
    clear in interface PreparedQueryCache
  - setEnableStatistics
```
public void setEnableStatistics(boolean enable)
```
    Description copied from interface: PreparedQueryCache
    
    Enable/disable gathering of statistics.
    
    Specified by:
    
    setEnableStatistics in interface PreparedQueryCache
  - getEnableStatistics
```
public boolean getEnableStatistics()
```
    Description copied from interface: PreparedQueryCache
    
    Affirm if statistics is gathered.
    
    Specified by:
    
    getEnableStatistics in interface PreparedQueryCache
  - setMaxCacheSize
```
public void setMaxCacheSize(int size)
```
  - getCacheSize
```
public int getCacheSize()
```
  - setConfiguration
```
public void setConfiguration(Configuration conf)
```
    Description copied from interface: Configurable
    
    Invoked prior to setting bean properties.
    
    Specified by:
    
    setConfiguration in interface Configurable
  - startConfiguration
```
public void startConfiguration()
```
    Description copied from interface: Configurable
    
    Invoked before bean property configuration is begun on this object.
    
    Specified by:
    
    startConfiguration in interface Configurable
  - endConfiguration
```
public void endConfiguration()
```
    Description copied from interface: Configurable
    
    Invoked upon completion of bean property configuration for this object.
    
    Specified by:
    
    endConfiguration in interface Configurable

Class PreparedQueryCacheImpl

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.openjpa.kernel.PreparedQueryCache

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

PreparedQueryCacheImpl

Method Detail

register

getMapView

cache

initialize

invalidate

get

isCachable

markUncachable

isExcluded

setExcludes

getExcludes

addExclusionPattern

removeExclusionPattern

getStatistics

lock

unlock

clear

setEnableStatistics

getEnableStatistics

setMaxCacheSize

getCacheSize

setConfiguration

startConfiguration

endConfiguration