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/**
* Copyright Terracotta, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.sf.ehcache.store;
import net.sf.ehcache.CacheException;
import net.sf.ehcache.Element;
import net.sf.ehcache.Status;
import net.sf.ehcache.search.Attribute;
import net.sf.ehcache.search.Results;
import net.sf.ehcache.search.SearchException;
import net.sf.ehcache.search.attribute.AttributeExtractor;
import net.sf.ehcache.terracotta.TerracottaNotRunningException;
import net.sf.ehcache.writer.CacheWriterManager;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* This is the interface for all stores. A store is a physical counterpart to a cache, which
* is a logical concept.
*
* @author Greg Luck
* @version $Id: Store.java 7824 2013-07-23 01:54:39Z vfunshte $
*/
public interface Store {
/**
* clusterCoherent property
*/
static final String CLUSTER_COHERENT = "ClusterCoherent";
/**
* nodeCoherent property
*/
static final String NODE_COHERENT = "NodeCoherent";
/**
* Add a listener to the store.
* @param listener
*/
void addStoreListener(StoreListener listener);
/**
* Remove listener from store.
* @param listener
*/
void removeStoreListener(StoreListener listener);
/**
* Puts an item into the store.
* @return true if this is a new put for the key or element is null. Returns false if it was an update.
*/
boolean put(Element element) throws CacheException;
/**
* Puts a collection of elements into the store.
* @param elements Collection of elements to be put in the store
*/
void putAll(Collection elements) throws CacheException;
/**
* Puts an item into the store and the cache writer manager in an atomic operation
* @return true if this is a new put for the key or element is null. Returns false if it was an update.
*/
boolean putWithWriter(Element element, CacheWriterManager writerManager) throws CacheException;
/**
* Gets an item from the cache.
*/
Element get(Object key);
/**
* Gets an {@link Element} from the Store, without updating statistics
*
* @return The element
*/
Element getQuiet(Object key);
/**
* Gets an Array of the keys for all elements in the disk store.
*
* @return An List of {@link java.io.Serializable} keys
*/
List getKeys();
/**
* Removes an item from the cache.
*
* @since signature changed in 1.2 from boolean to Element to support notifications
*/
Element remove(Object key);
/**
* Removes a collection of elements from the cache.
*/
void removeAll(Collection keys);
/**
* Removes an item from the store and the cache writer manager in an atomic operation.
*/
Element removeWithWriter(Object key, CacheWriterManager writerManager) throws CacheException;
/**
* Remove all of the elements from the store.
*
* If there are registered CacheEventListeners they are notified of the expiry or removal
* of the Element as each is removed.
*/
void removeAll() throws CacheException;
/**
* Put an element in the store if no element is currently mapped to the elements key.
*
* @param element element to be added
* @return the element previously cached for this key, or null if none.
*
* @throws NullPointerException if the element is null, or has a null key
*/
Element putIfAbsent(Element element) throws NullPointerException;
/**
* Remove the Element mapped to the key for the supplied element if the value of the supplied Element
* is equal to the value of the cached Element. This is a CAS operation. It is consistent even against
* a distributed cache that is not coherent. If the old value is stale when this operation is attempted
* the remove does not take place.
*
* @param element Element to be removed
* @param comparator ElementValueComparator to use to compare elements
* @return the Element removed or null if no Element was removed
*
* @throws NullPointerException if the element is null, or has a null key
*/
Element removeElement(Element element, ElementValueComparator comparator) throws NullPointerException;
/**
* Replace the cached element only if the value of the current Element is equal to the value of the
* supplied old Element.
*
* @param old Element to be test against
* @param element Element to be cached
* @param comparator ElementValueComparator to use to compare elements
* @return true is the Element was replaced
* @throws NullPointerException if the either Element is null or has a null key
* @throws IllegalArgumentException if the two Element keys are non-null but not equal
*/
boolean replace(Element old, Element element, ElementValueComparator comparator) throws NullPointerException, IllegalArgumentException;
/**
* Replace the cached element only if an Element is currently cached for this key
* @param element Element to be cached
* @return the Element previously cached for this key, or null if no Element was cached
* @throws NullPointerException if the Element is null or has a null key
*/
Element replace(Element element) throws NullPointerException;
/**
* Prepares for shutdown.
*/
void dispose();
/**
* Returns the current local store size
* @return the count of the Elements in the Store on the local machine
*/
int getSize();
/**
* Returns the current local in-memory store size
* @return the count of the Elements in the Store and in-memory on the local machine
*/
int getInMemorySize();
/**
* Returns the current local off-heap store size
* @return the count of the Elements in the Store and off-heap on the local machine
*/
int getOffHeapSize();
/**
* Returns the current local on-disk store size
* @return the count of the Elements in the Store and on-disk on the local machine
*/
int getOnDiskSize();
/**
* Returns the current Terracotta clustered store size
* @return the count of the Elements in the Store across the cluster
*/
int getTerracottaClusteredSize();
/**
* Gets the size of the in-memory portion of the store, in bytes.
*
* This method may be expensive to run, depending on implementation. Implementers may choose to return
* an approximate size.
*
* @return the approximate in-memory size of the store in bytes
*/
long getInMemorySizeInBytes();
/**
* Gets the size of the off-heap portion of the store, in bytes.
*
* @return the approximate off-heap size of the store in bytes
*/
long getOffHeapSizeInBytes();
/**
* Gets the size of the on-disk portion of the store, in bytes.
*
* @return the on-disk size of the store in bytes
*/
long getOnDiskSizeInBytes();
/**
* Checks if the cache may contain elements for which the SizeOf engine gave up and only
* partially calculated the size.
*
* @return true if at least one partially sized element may be in the cache
*/
boolean hasAbortedSizeOf();
/**
* Returns the cache status.
*/
Status getStatus();
/**
* A check to see if a key is in the Store.
*
* @param key The Element key
* @return true if found. No check is made to see if the Element is expired.
* 1.2
*/
boolean containsKey(Object key);
/**
* A check to see if a key is in the Store and is currently held on disk.
*
* @param key The Element key
* @return true if found. No check is made to see if the Element is expired.
*/
boolean containsKeyOnDisk(Object key);
/**
* A check to see if a key is in the Store and is currently held off-heap.
*
* @param key The Element key
* @return true if found. No check is made to see if the Element is expired.
*/
boolean containsKeyOffHeap(Object key);
/**
* A check to see if a key is in the Store and is currently held in memory.
*
* @param key The Element key
* @return true if found. No check is made to see if the Element is expired.
*/
boolean containsKeyInMemory(Object key);
/**
* Expire all elements.
*/
public void expireElements();
/**
* Flush elements to persistent store.
* @throws IOException if any IO error occurs
*/
void flush() throws IOException;
/**
* Some store types, such as the disk stores can fill their write buffers if puts
* come in too fast. The thread will wait for a short time before checking again.
* @return true if the store write buffer is backed up.
*/
boolean bufferFull();
/**
* @return the current eviction policy. This may not be the configured policy, if it has been
* dynamically set.
* @see #setInMemoryEvictionPolicy(Policy)
*/
Policy getInMemoryEvictionPolicy();
/**
* Sets the eviction policy strategy. The Store will use a policy at startup. The store may allow changing
* the eviction policy strategy dynamically. Otherwise implementations will throw an exception if this method
* is called.
*
* @param policy the new policy
*/
void setInMemoryEvictionPolicy(Policy policy);
/**
* This should not be used, and will generally return null
* @return some internal context (probably null)
*/
Object getInternalContext();
/**
* Indicates whether this store provides a coherent view of all the elements
* in a cache.
*
* Note that this is same as calling {@link #isClusterCoherent()} (introduced since 2.0)
* Use {@link #isNodeCoherent()} to find out if the cache is coherent in the current node in the cluster
*
* @return {@code true} if the store is coherent; or {@code false} if the
* store potentially splits the cache storage with another store or
* isn't internally coherent
* @since 1.7
*/
boolean isCacheCoherent();
/**
* Returns true if the cache is in coherent mode cluster-wide. Returns false otherwise.
*
* It applies to coherent clustering mechanisms only e.g. Terracotta
*
* @return true if the cache is in coherent mode cluster-wide, false otherwise
* @since 2.0
*/
public boolean isClusterCoherent() throws TerracottaNotRunningException;
/**
* Returns true if the cache is in coherent mode for the current node. Returns false otherwise.
*
* It applies to coherent clustering mechanisms only e.g. Terracotta
*
* @return true if the cache is in coherent mode cluster-wide, false otherwise
* @since 2.0
*/
public boolean isNodeCoherent() throws TerracottaNotRunningException;
/**
* Sets the cache in coherent or incoherent mode for the current node depending on the parameter.
* Calling {@code setNodeCoherent(true)} when the cache is already in coherent mode or
* calling {@code setNodeCoherent(false)} when already in incoherent mode will be a no-op.
*
* It applies to coherent clustering mechanisms only e.g. Terracotta
*
* @param coherent
* true transitions to coherent mode, false to incoherent mode
* @throws UnsupportedOperationException if this store does not support cache coherence, like RMI replication
* @since 2.0
*/
public void setNodeCoherent(boolean coherent) throws UnsupportedOperationException, TerracottaNotRunningException;
/**
* This method waits until the cache is in coherent mode in all the connected nodes. If the cache is already in coherent mode it returns
* immediately
*
* It applies to coherent clustering mechanisms only e.g. Terracotta
* @throws UnsupportedOperationException if this store does not support cache coherence, like RMI replication
* @throws InterruptedException
* @since 2.0
*/
public void waitUntilClusterCoherent() throws UnsupportedOperationException, TerracottaNotRunningException, InterruptedException;
/**
* Optional implementation specific MBean exposed by the store.
*
* @return implementation specific management bean
*/
public Object getMBean();
/**
* Inform this store of the configured attribute extractors. Stores that will not invoke extractors are free to ignore this call
*
* @param extractors
*/
public void setAttributeExtractors(Map extractors);
/**
* Execute the given query on this store
*
* @param query query to execute
* @return query results
*/
public Results executeQuery(StoreQuery query) throws SearchException;
/**
* @return all search attributes known to this store at the time of invoking the method
*/
public Set getSearchAttributes();
/**
* Retrieve the given named search attribute
*
* @param type of the attribute
* @param attributeName the name of the attribute to retrieve
* @return the search attribute or null if non-existent
*/
public Attribute getSearchAttribute(String attributeName);
/**
* Retries the elements associated with a set of keys without updating the statistics
* Keys which are not present in the cache will have null values associated
* with them in the returned map
*
* @param keys a collection of keys to look for
* @return a map of keys and their corresponding values
*/
Map getAllQuiet(Collection keys);
/**
* Retries the elements associated with a set of keys and update the statistics
* Keys which are not present in the cache will have null values associated
* with them in the returned map
*
* @param keys a collection of keys to look for
* @return a map of keys and their corresponding values
*/
Map getAll(Collection keys);
/**
* Recalculate size of the element mapped to the key
* @param key the key
*/
void recalculateSize(Object key);
}
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