[feature] add expireAfterWrite to cache configuration

Author: Nico Verwer

extensions/modules/cache/src/main/java/org/exist/xquery/modules/cache/Cache.java

@@ -48,6 +48,7 @@ public Cache(final CacheConfig config) {
 
         config.getMaximumSize().map(cacheBuilder::maximumSize);
         config.getExpireAfterAccess().map(ms -> cacheBuilder.expireAfterAccess(ms, TimeUnit.MILLISECONDS));
+        config.getExpireAfterWrite().map(ms -> cacheBuilder.expireAfterWrite(ms, TimeUnit.MILLISECONDS));
 
         this.store = cacheBuilder.build();
 	}

extensions/modules/cache/src/main/java/org/exist/xquery/modules/cache/CacheConfig.java

@@ -33,16 +33,19 @@ public class CacheConfig {
     private final Optional<Permissions> permissions;
     private final Optional<Long> maximumSize;
     private final Optional<Long> expireAfterAccess;
+    private final Optional<Long> expireAfterWrite;
 
     /**
      * @param permissions Any restrictions on cache operations
      * @param maximumSize The maximimum number of entries in the cache
      * @param expireAfterAccess The time in milliseconds after the entry is last accessed, that it should expire
+     * @param expireAfterWrite The time in milliseconds after the entry is last modified, that it should expire
      */
-    public CacheConfig(final Optional<Permissions> permissions, final Optional<Long> maximumSize, final Optional<Long> expireAfterAccess) {
+    public CacheConfig(final Optional<Permissions> permissions, final Optional<Long> maximumSize, final Optional<Long> expireAfterAccess, final Optional<Long> expireAfterWrite) {
         this.permissions = permissions;
         this.maximumSize = maximumSize;
         this.expireAfterAccess = expireAfterAccess;
+        this.expireAfterWrite = expireAfterWrite;
     }
 
     public Optional<Permissions> getPermissions() {
@@ -57,6 +60,10 @@ public Optional<Long> getExpireAfterAccess() {
         return expireAfterAccess;
     }
 
+    public Optional<Long> getExpireAfterWrite() {
+        return expireAfterWrite;
+    }
+
     public static class Permissions {
         private final Optional<String> putGroup;
         private final Optional<String> getGroup;

extensions/modules/cache/src/main/java/org/exist/xquery/modules/cache/CacheFunctions.java

@@ -62,7 +62,7 @@ public class CacheFunctions extends BasicFunction {
             "Explicitly create a cache with a specific configuration",
             returns(Type.BOOLEAN, "true if the cache was created, false if the cache already exists"),
             FS_PARAM_CACHE_NAME,
-            param("config", Type.MAP, "A map with configuration for the cache. At present cache LRU and permission groups may be specified, for operations on the cache. `maximumSize` is optional and specifies the maximum number of entries. `expireAfterAccess` is optional and specifies the expiry period for infrequently accessed entries (in milliseconds). If a permission group is not specified for an operation, then permissions are not checked for that operation. Should have the format: map { \"maximumSize\": 1000, \"expireAfterAccess\": 120000, \"permissions\": map { \"put-group\": \"group1\", \"get-group\": \"group2\", \"remove-group\": \"group3\", \"clear-group\": \"group4\"} }")
+            param("config", Type.MAP, "A map with configuration for the cache. At present cache LRU and permission groups may be specified, for operations on the cache. `maximumSize` is optional and specifies the maximum number of entries. `expireAfterAccess` is optional and specifies the expiry period for infrequently accessed entries (in milliseconds). `expireAfterWrite` is optional and specifies the expiry period after the entry's creation, or the most recent replacement of its value (in milliseconds). If a permission group is not specified for an operation, then permissions are not checked for that operation. Should have the format: map { \"maximumSize\": 1000, \"expireAfterAccess\": 120000, \"expireAfterWrite\": 240000, \"permissions\": map { \"put-group\": \"group1\", \"get-group\": \"group2\", \"remove-group\": \"group3\", \"clear-group\": \"group4\"} }")
     );
 
     private static final String FS_NAMES_NAME = "names";
@@ -277,7 +277,16 @@ private CacheConfig extractCacheConfig(final MapType configMap) throws XPathExce
             expireAfterAccess = Optional.empty();
         }
 
-        return new CacheConfig(permissions, maximumSize, expireAfterAccess);
+        final Sequence expireAfterWriteSeq = configMap.get(new StringValue(this, "expireAfterWrite"));
+        final Optional<Long> expireAfterWrite;
+        if(expireAfterWriteSeq != null && expireAfterWriteSeq.getItemCount() == 1) {
+            final long l = expireAfterWriteSeq.itemAt(0).toJavaObject(Long.class);
+            expireAfterWrite = Optional.of(l);
+        } else {
+            expireAfterWrite = Optional.empty();
+        }
+
+        return new CacheConfig(permissions, maximumSize, expireAfterAccess, expireAfterWrite);
     }
 
     private Optional<String> getStringValue(final String key, final AbstractMapType map) {

extensions/modules/cache/src/main/java/org/exist/xquery/modules/cache/CacheModule.java

@@ -71,13 +71,15 @@ public class CacheModule extends AbstractInternalModule {
     private static final String PARAM_NAME_ENABLE_LAZY_CREATION = "enableLazyCreation";
     private static final String PARAM_NAME_LAZY_MAXIMUM_SIZE = "lazy.maximumSize";
     private static final String PARAM_NAME_LAZY_EXPIRE_AFTER_ACCESS = "lazy.expireAfterAccess";
+    private static final String PARAM_NAME_LAZY_EXPIRE_AFTER_WRITE = "lazy.expireAfterWrite";
     private static final String PARAM_NAME_LAZY_PUT_GROUP = "lazy.putGroup";
     private static final String PARAM_NAME_LAZY_GET_GROUP = "lazy.getGroup";
     private static final String PARAM_NAME_LAZY_REMOVE_GROUP = "lazy.removeGroup";
     private static final String PARAM_NAME_LAZY_CLEAR_GROUP = "lazy.clearGroup";
 
     private static final long DEFAULT_LAZY_MAXIMUM_SIZE = 128;  // 128 items
     private static final long DEFAULT_LAZY_EXPIRE_AFTER_ACCESS = 1000 * 60 * 5;  // 5 minutes
+    private static final long DEFAULT_LAZY_EXPIRE_AFTER_WRITE = 1000 * 60 * 5;  // 5 minutes
 
     static final Map<String, Cache> caches = new ConcurrentHashMap<>();
 
@@ -167,8 +169,18 @@ private static Optional<CacheConfig> parseParameters(final Map<String, List<?>>
                     }
                 });
 
+        final Optional<Long> expireAfterWrite = getFirstString(parameters, PARAM_NAME_LAZY_EXPIRE_AFTER_WRITE)
+                .map(s -> {
+                    try {
+                        return Long.parseLong(s);
+                    } catch (final NumberFormatException e) {
+                        LOG.warn("Unable to set {} to: {}. Using default: ", PARAM_NAME_LAZY_EXPIRE_AFTER_WRITE, s, DEFAULT_LAZY_EXPIRE_AFTER_WRITE);
+                        return DEFAULT_LAZY_EXPIRE_AFTER_ACCESS;
+                    }
+                });
+
 
-        return Optional.of(new CacheConfig(permissions, maximumSize, expireAfterAccess));
+        return Optional.of(new CacheConfig(permissions, maximumSize, expireAfterAccess, expireAfterWrite));
     }
 
     private static Optional<String> getFirstString(final Map<String, List<?>> parameters, final String paramName) {

extensions/modules/cache/src/test/xquery/modules/cache/cache.xqm

@@ -33,6 +33,8 @@ declare variable $c:maximumSize := 5;
 declare variable $c:maximumSize-options := map { "maximumSize": $c:maximumSize };
 declare variable $c:expireAfterAccess := 1000;
 declare variable $c:expireAfterAccess-options := map { "expireAfterAccess": $c:expireAfterAccess };
+declare variable $c:expireAfterWrite := 1000;
+declare variable $c:expireAfterWrite-options := map { "expireAfterWrite": $c:expireAfterWrite };
 
 declare function c:_create-simple() {
     cache:create($c:cache-name, $c:simple-options)
@@ -46,6 +48,10 @@ declare function c:_create-expireAfterAccess() {
     cache:create($c:cache-name, $c:expireAfterAccess-options)
 };
 
+declare function c:_create-expireAfterWrite() {
+    cache:create($c:cache-name, $c:expireAfterWrite-options)
+};
+
 declare function c:_populate($size as xs:integer) {
     (1 to $size) ! cache:put($c:cache-name, "foo" || ., "bar" || .)
 };
@@ -171,6 +177,21 @@ function c:exercise-expireAfterAccess() {
         count(c:_keys())
 };
 
+declare
+    %test:assertEquals(0)
+function c:exercise-expireAfterWrite() {
+    let $setup := 
+        (
+            c:_destroy(),
+            c:_create-expireAfterWrite(),
+            c:_populate(5),
+            util:wait($c:expireAfterWrite * 1.1),
+            c:_cleanup()
+        )
+    return
+        count(c:_keys())
+};
+
 declare
     %test:assertEquals("bar5")
 function c:get() {