org.eclipse.persistence.queries.QueryResultsCachePolicy Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of eclipselink Show documentation
Show all versions of eclipselink Show documentation
EclipseLink build based upon Git transaction f2b9fc5
/*
* Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0,
* or the Eclipse Distribution License v. 1.0 which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
*/
// Contributors:
// Oracle - initial API and implementation from Oracle TopLink
package org.eclipse.persistence.queries;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import org.eclipse.persistence.descriptors.invalidation.*;
import org.eclipse.persistence.internal.helper.ClassConstants;
import org.eclipse.persistence.internal.identitymaps.IdentityMap;
/**
* PUBLIC:
*
* A QueryResultsCache policy dictates how a query's results will be cached.
*
* It allows an invalidation policy and a maximum number of results to be set.
* Query results are cached based on the parameter values of a query, and the maximum number
* of results refers to the maximum number of parameter sets results will be cached for.\
* By default query result caching is not used.
*
* @see org.eclipse.persistence.queries.ReadQuery#setQueryResultsCachePolicy(QueryResultsCachePolicy)
*/
public class QueryResultsCachePolicy implements Serializable, Cloneable {
/** Allows invalidation to be specified. */
protected CacheInvalidationPolicy invalidationPolicy;
/** Specifies the cache size. */
protected int maximumResultSets;
/** Allows the identity map class type to be set. */
protected Class cacheType;
/** Allows the caching of null to be configured. */
protected boolean isNullIgnored;
/** Allows the query cache to be invalidated when any object of any of the query classes is modified. */
protected boolean invalidateOnChange;
/** Stores the set of classes that should trigger the query cached results to be invalidated. */
protected Set> invalidationClasses;
/**
* PUBLIC:
* Build a QueryResultsCachePolicy with the default settings
* By default there is no invalidation of query results and the maximum
* number of results sets is 100.
*/
public QueryResultsCachePolicy() {
this(new NoExpiryCacheInvalidationPolicy(), 100);
}
/**
* PUBLIC:
* Build a QueryResultsCachePolicy and supply a CacheInvalidationPolicy and a maximum
* number of results sets.
*
* @see org.eclipse.persistence.descriptors.invalidation.CacheInvalidationPolicy
*/
public QueryResultsCachePolicy(CacheInvalidationPolicy policy, int maximumResultSets) {
this.invalidationPolicy = policy;
this.maximumResultSets = maximumResultSets;
this.cacheType = ClassConstants.CacheIdentityMap_Class;
this.isNullIgnored = false;
this.invalidateOnChange = true;
this.invalidationClasses = new HashSet<>();
}
@Override
public QueryResultsCachePolicy clone() {
try {
QueryResultsCachePolicy clone = (QueryResultsCachePolicy)super.clone();
clone.invalidationClasses = new HashSet<>();
return clone;
} catch (CloneNotSupportedException exception) {
throw new InternalError(exception.toString());
}
}
/**
* ADVANCED:
* Return the set of classes that should trigger the query cached results to be invalidated.
*/
public Set> getInvalidationClasses() {
return invalidationClasses;
}
/**
* ADVANCED:
* Set the set of classes that should trigger the query cached results to be invalidated.
* This is normally computed by the query, but can be set in the case of native queries.
*/
public void setInvalidationClasses(Set> invalidationClasses) {
this.invalidationClasses = invalidationClasses;
}
/**
* PUBLIC:
* Return if null results should be cached or ignored.
* By default they are cached.
* They can be ignored to allow a query cache to be used as a secondary cache index,
* and allow new objects to be insert, and still found.
*/
public boolean isNullIgnored() {
return isNullIgnored;
}
/**
* PUBLIC:
* Set if null results should be cached or ignored.
* By default they are cached.
* They can be ignored to allow a query cache to be used as a secondary cache index,
* and allow new objects to be insert, and still found.
*/
public void setIsNullIgnored(boolean isNullIgnored) {
this.isNullIgnored = isNullIgnored;
}
/**
* PUBLIC:
* Return if any change to any object of the query class should cause the query results to be invalidated.
*/
public boolean getInvalidateOnChange() {
return invalidateOnChange;
}
/**
* PUBLIC:
* Configure if any change to any object of the query class should cause the query results to be invalidated.
*/
public void setInvalidateOnChange(boolean invalidateOnChange) {
this.invalidateOnChange = invalidateOnChange;
}
/**
* PUBLIC:
* Return the type of the cache used for the query results.
* This defaults to a LRU cache (CacheIdentityMap), but can be
* set to any IdentityMap class, such as Full or Soft.
*/
public Class getCacheType() {
return cacheType;
}
/**
* PUBLIC:
* Set the type of the cache used for the query results.
* This defaults to a LRU cache (CacheIdentityMap), but can be
* set to any IdentityMap class, such as Full or Soft.
*/
public void setCacheType(Class cacheType) {
this.cacheType = cacheType;
}
/**
* PUBLIC:
* Set the type of the cache used for the query results to a FullIdentityMap.
* This will cache all query results, so caution should be used to avoid running out of memory.
*/
public void useFullCache() {
setCacheType(ClassConstants.FullIdentityMap_Class);
}
/**
* PUBLIC:
* Set the type of the cache used for the query results to a SoftIdentityMap.
* This will cache all query results, unless the JVM believes memory is low.
*/
public void useSoftCache() {
setCacheType(ClassConstants.SoftIdentityMap_Class);
}
/**
* PUBLIC:
* Set the type of the cache used for the query results to a SoftCacheWeakIdentityMap.
* This will uses a fixed size LRU cache using Soft references, so will allow garbage collection when memory is low.
*/
public void useSoftLRUCache() {
setCacheType(ClassConstants.SoftCacheWeakIdentityMap_Class);
}
/**
* PUBLIC:
* Set the type of the cache used for the query results to a CacheIdentityMap.
* This will uses a fixed size LRU cache.
* This is the default.
*/
public void useLRUCache() {
setCacheType(ClassConstants.CacheIdentityMap_Class);
}
/**
* PUBLIC:
* Build a QueryResultsCachePolicy and supply a CacheInvalidationPolicy. The default
* value of 100 will be used for the maximum number of result sets
*
* @see org.eclipse.persistence.descriptors.invalidation.CacheInvalidationPolicy
*/
public QueryResultsCachePolicy(CacheInvalidationPolicy policy) {
this(policy, 100);
}
/**
* PUBLIC:
* Build a QueryResultsCachePolicy and supply a maximum for the number of results sets.
* Results will be set not to expire in the cache.
*/
public QueryResultsCachePolicy(int maximumResultSets) {
this(new NoExpiryCacheInvalidationPolicy(), maximumResultSets);
}
/**
* PUBLIC:
* Return the query cache invalidation policy.
* The cache invalidation policy defines how the query results are invalidated.
*/
public CacheInvalidationPolicy getCacheInvalidationPolicy() {
return invalidationPolicy;
}
/**
* PUBLIC:
* Set the query cache invalidation policy.
* The cache invalidation policy defines how the query results are invalidated.
*/
public void setCacheInvalidationPolicy(CacheInvalidationPolicy invalidationPolicy) {
this.invalidationPolicy = invalidationPolicy;
}
/**
* PUBLIC:
* Return the maximum cached results.
* This defines the number of query result sets that will be cached.
* The LRU query results will be discarded when the max size is reached.
*/
public int getMaximumCachedResults() {
return maximumResultSets;
}
/**
* PUBLIC:
* Set the maximum cached results.
* This defines the number of query result sets that will be cached.
* The LRU query results will be discarded when the max size is reached.
*/
public void setMaximumCachedResults(int maximumResultSets) {
this.maximumResultSets = maximumResultSets;
}
}