Add a get method to CacheAccess that allows a Supplier to be specified
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/jcs/trunk@1852302 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/CacheAccess.java b/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/CacheAccess.java
index 7fe0a73..71095eb 100644
--- a/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/CacheAccess.java
+++ b/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/CacheAccess.java
@@ -23,6 +23,7 @@
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
+import java.util.function.Supplier;
import java.util.stream.Collectors;
import org.apache.commons.jcs.access.behavior.ICacheAccess;
@@ -80,6 +81,29 @@
}
/**
+ * Retrieve an object from the cache region this instance provides access to.
+ * If the object cannot be found in the cache, it will be retrieved by
+ * calling the supplier and subsequently storing it in the cache.
+ * <p>
+ * @param name
+ * @param supplier supplier to be called if the value is not found
+ * @return Object.
+ */
+ @Override
+ public V get(K name, Supplier<V> supplier)
+ {
+ V value = get(name);
+
+ if (value == null)
+ {
+ value = supplier.get();
+ put(name, value);
+ }
+
+ return value;
+ }
+
+ /**
* Retrieve matching objects from the cache region this instance provides access to.
* <p>
* @param pattern - a key pattern for the objects stored
diff --git a/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/PartitionedCacheAccess.java b/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/PartitionedCacheAccess.java
index e100002..a12e039 100644
--- a/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/PartitionedCacheAccess.java
+++ b/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/PartitionedCacheAccess.java
@@ -24,6 +24,7 @@
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
+import java.util.function.Supplier;
import org.apache.commons.jcs.JCS;
import org.apache.commons.jcs.access.behavior.ICacheAccess;
@@ -205,6 +206,29 @@
}
/**
+ * Retrieve an object from the cache region this instance provides access to.
+ * If the object cannot be found in the cache, it will be retrieved by
+ * calling the supplier and subsequently storing it in the cache.
+ * <p>
+ * @param name
+ * @param supplier supplier to be called if the value is not found
+ * @return Object.
+ */
+ @Override
+ public V get(K name, Supplier<V> supplier)
+ {
+ V value = get(name);
+
+ if (value == null)
+ {
+ value = supplier.get();
+ put(name, value);
+ }
+
+ return value;
+ }
+
+ /**
* Gets the ICacheElement<K, V> (the wrapped object) for the key from the desired partition.
* <p>
* @param key key
diff --git a/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/behavior/ICacheAccess.java b/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/behavior/ICacheAccess.java
index 7c0db96..f48abdd 100644
--- a/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/behavior/ICacheAccess.java
+++ b/commons-jcs-core/src/main/java/org/apache/commons/jcs/access/behavior/ICacheAccess.java
@@ -1,5 +1,9 @@
package org.apache.commons.jcs.access.behavior;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Supplier;
+
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
@@ -23,9 +27,6 @@
import org.apache.commons.jcs.engine.behavior.ICacheElement;
import org.apache.commons.jcs.engine.behavior.IElementAttributes;
-import java.util.Map;
-import java.util.Set;
-
/**
* ICacheAccess defines the behavior for client access.
*/
@@ -38,7 +39,17 @@
* @param name
* @return Object or null if not found.
*/
- V get( K name );
+ V get(K name);
+
+ /**
+ * Basic get method. If the object cannot be found in the cache, it will be
+ * retrieved by calling the supplier and subsequently storing it in the cache.
+ * <p>
+ * @param name
+ * @param supplier supplier to be called if the value is not found
+ * @return Object.
+ */
+ V get(K name, Supplier<V> supplier);
/**
* Retrieve matching objects from the cache region this instance provides access to.
@@ -46,7 +57,7 @@
* @param pattern - a key pattern for the objects stored
* @return A map of key to values. These are stripped from the wrapper.
*/
- Map<K, V> getMatching( String pattern );
+ Map<K, V> getMatching(String pattern);
/**
* Puts in cache if an item does not exist with the name in that region.
@@ -55,7 +66,7 @@
* @param obj
* @throws CacheException
*/
- void putSafe( K name, V obj )
+ void putSafe(K name, V obj)
throws CacheException;
/**
@@ -65,7 +76,7 @@
* @param obj
* @throws CacheException
*/
- void put( K name, V obj )
+ void put(K name, V obj)
throws CacheException;
/**
@@ -76,7 +87,7 @@
* @param attr
* @throws CacheException
*/
- void put( K name, V obj, IElementAttributes attr )
+ void put(K name, V obj, IElementAttributes attr)
throws CacheException;
/**
@@ -94,7 +105,7 @@
* @param name Key the object is stored as
* @return The ICacheElement<K, V> if the object is found or null
*/
- ICacheElement<K, V> getCacheElement( K name );
+ ICacheElement<K, V> getCacheElement(K name);
/**
* Get multiple elements from the cache based on a set of cache keys.
@@ -114,7 +125,7 @@
* @return a map of Object key to ICacheElement<K, V> element, or empty map if none of the keys are
* present
*/
- Map<K, ICacheElement<K, V>> getCacheElements( Set<K> names );
+ Map<K, ICacheElement<K, V>> getCacheElements(Set<K> names);
/**
* Get multiple elements from the cache based on a set of cache keys.
@@ -134,7 +145,7 @@
* @return a map of Object key to ICacheElement<K, V> element, or empty map if no keys match the
* pattern
*/
- Map<K, ICacheElement<K, V>> getMatchingCacheElements( String pattern );
+ Map<K, ICacheElement<K, V>> getMatchingCacheElements(String pattern);
/**
* Remove an object for this key if one exists, else do nothing.
@@ -142,7 +153,7 @@
* @param name
* @throws CacheException
*/
- void remove( K name )
+ void remove(K name)
throws CacheException;
/**
@@ -152,7 +163,7 @@
* @param attributes
* @throws CacheException
*/
- void resetElementAttributes( K name, IElementAttributes attributes )
+ void resetElementAttributes(K name, IElementAttributes attributes)
throws CacheException;
/**
@@ -162,6 +173,6 @@
* @return The elementAttributes value
* @throws CacheException
*/
- IElementAttributes getElementAttributes( K name )
+ IElementAttributes getElementAttributes(K name)
throws CacheException;
}
diff --git a/commons-jcs-core/src/test/java/org/apache/commons/jcs/access/CacheAccessUnitTest.java b/commons-jcs-core/src/test/java/org/apache/commons/jcs/access/CacheAccessUnitTest.java
index 900323e..7e5b30a 100644
--- a/commons-jcs-core/src/test/java/org/apache/commons/jcs/access/CacheAccessUnitTest.java
+++ b/commons-jcs-core/src/test/java/org/apache/commons/jcs/access/CacheAccessUnitTest.java
@@ -167,9 +167,11 @@
String keyOne = "mykeyone";
String keyTwo = "mykeytwo";
String keyThree = "mykeythree";
+ String keyFour = "mykeyfour";
String valueOne = "myvalueone";
String valueTwo = "myvaluetwo";
String valueThree = "myvaluethree";
+ String valueFour = "myvaluefour";
access.put( keyOne, valueOne );
access.put( keyTwo, valueTwo );
@@ -190,6 +192,14 @@
ICacheElement<String, String> elementTwo = result.get( keyTwo );
assertEquals( "value two", keyTwo, elementTwo.getKey() );
assertEquals( "value two", valueTwo, elementTwo.getVal() );
+
+ assertNull(access.get(keyFour));
+ String suppliedValue1 = access.get(keyFour, () -> valueFour);
+ assertNotNull( "value four", suppliedValue1);
+ assertEquals( "value four", valueFour, suppliedValue1);
+ String suppliedValue2 = access.get(keyFour);
+ assertNotNull( "value four", suppliedValue2);
+ assertEquals( "value four", suppliedValue1, suppliedValue2);
}
/**
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 4376e99..898be86 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -20,6 +20,9 @@
</properties>
<body>
<release version="3.0" date="unreleased">
+ <action dev="tv" type="add">
+ Add a get method to CacheAccess that allows a Supplier to be specified
+ </action>
<action dev="tv" type="remove">
Remove dependency on velocity-tools
</action>
diff --git a/xdocs/UsingJCSBasicWeb.xml b/xdocs/UsingJCSBasicWeb.xml
index b54f6d8..7e139e3 100644
--- a/xdocs/UsingJCSBasicWeb.xml
+++ b/xdocs/UsingJCSBasicWeb.xml
@@ -214,18 +214,14 @@
{
BookVObj vObj = null;
- // First, if requested, attempt to load from cache
-
+ // If requested, attempt to load from cache
if (fromCache)
{
- vObj = bookCache.get("BookVObj" + id);
+ vObj = bookCache.get("BookVObj" + id, () -> loadvObj(id));
}
-
- // Either fromCache was false or the object was not found, so
- // call loadBookVObj to create it
-
- if (vObj == null)
+ else
{
+ // otherwise, load directly
vObj = loadvObj(id);
}
