Package org.gcube.informationsystem.resourceregistry.api.contexts

Class ContextCache

  • public class ContextCache
extends Object
    Client-side, time-expiring singleton cache of the full Context tree, indexed by UUID and by path, used by client libraries to resolve Context identity without a server round-trip on every call. Populated/refreshed via a pluggable ContextCacheRenewal strategy and automatically renewed once expiringTimeout elapses.
    Author:
    Luca Frosini (ISTI - CNR)

    • Field Detail

      • DEFAULT_EXPIRING_TIMEOUT

        public static final long DEFAULT_EXPIRING_TIMEOUT
        Default cache validity period, in milliseconds: 6 hours.

      • MISS_RENEWAL_INTERVAL

        public static final long MISS_RENEWAL_INTERVAL
        The shortest time between two renewals caused by a missing Context, in milliseconds: 1 minute. A Context created or reached after the last renewal is found at the first lookup that misses it, without waiting for expiringTimeout; a Context that does not exist costs at most one renewal a minute.

      • expiringTimeout

        public static int expiringTimeout
        The currently configured cache validity period, in milliseconds; overridable via setExpiringTimeout(int).

      • singleton

        protected static ContextCache singleton
        The singleton.

      • contextCacheRenewal

        protected ContextCacheRenewal contextCacheRenewal
        The context cache renewal.

      • creationTime

        protected Calendar creationTime
        The creation time.

      • expiringTime

        protected Calendar expiringTime
        The expiring time.

      • contexts

        protected List<org.gcube.informationsystem.contexts.reference.entities.Context> contexts
        The contexts.

      • uuidToContext

        protected Map<UUID,​org.gcube.informationsystem.contexts.reference.entities.Context> uuidToContext
        The uuid to context.

      • uuidToContextPath

        protected Map<UUID,​String> uuidToContextPath
        The uuid to context path.

      • contextPathToUUID

        protected Map<String,​UUID> contextPathToUUID
        The context path to UUID.

      • previousPathToUUID

        protected Map<String,​UUID> previousPathToUUID
        The previous paths of the cached Contexts, each to the Context that holds it: a path that is the current path of a Context is never here, since the current path always wins.

      • contextsTree

        protected org.gcube.informationsystem.dag.Dag<org.gcube.informationsystem.contexts.reference.entities.Context> contextsTree
        The contexts tree.

      • initialized

        protected boolean initialized
        The initialized.

    • Constructor Detail

      • ContextCache

        public ContextCache()
        Instantiates a new context cache.

    • Method Detail

      • setExpiringTimeout

        public static void setExpiringTimeout​(int expiringTimeout)
        Sets the expiring timeout.
        Parameters:
        expiringTimeout - the new expiring timeout

      • getInstance

        public static ContextCache getInstance()
        Gets the single instance of ContextCache.
        Returns:
        single instance of ContextCache

      • cleanCache

        public void cleanCache()
        Clean cache.

      • cleanCache

        protected void cleanCache​(Calendar calendar)
        Clean cache.
        Parameters:
        calendar - the calendar

      • getContextCacheRenewal

        public ContextCacheRenewal getContextCacheRenewal()
        Gets the context cache renewal.
        Returns:
        the context cache renewal

      • setContextCacheRenewal

        public void setContextCacheRenewal​(ContextCacheRenewal contextCacheRenewal)
        Sets the context cache renewal.
        Parameters:
        contextCacheRenewal - the new context cache renewal

      • setContexts

        public void setContexts​(List<org.gcube.informationsystem.contexts.reference.entities.Context> contexts)
        Sets the contexts.
        Parameters:
        contexts - the new contexts

      • setContexts

        protected void setContexts​(Calendar calendar,
                           List<org.gcube.informationsystem.contexts.reference.entities.Context> contexts)
        Sets the contexts.
        Parameters:
        calendar - the calendar
        contexts - the contexts

      • getContextPath

        protected String getContextPath​(org.gcube.informationsystem.contexts.reference.entities.Context context)
        Gets the context path.
        Parameters:
        context - the context
        Returns:
        the context path

      • getUUIDByPath

        public UUID getUUIDByPath​(String contextPath)
                   throws ResourceRegistryException
        Gets the UUID of the Context a path names: its current path first, then one of its previous paths, as the Resource Registry resolves a token that still names a moved or renamed Context. A path found neither way renews the cache (see renewOnMiss()).
        Parameters:
        contextPath - the context path
        Returns:
        the uuid by path, or null if no Context has that path, current or previous
        Throws:
        ResourceRegistryException - the resource registry exception

      • getContextByUUID

        public org.gcube.informationsystem.contexts.reference.entities.Context getContextByUUID​(UUID uuid)
                                                                                 throws ResourceRegistryException
        Gets the context by UUID.
        Parameters:
        uuid - the uuid
        Returns:
        the context by UUID
        Throws:
        ResourceRegistryException - the resource registry exception

      • getContextByUUID

        public org.gcube.informationsystem.contexts.reference.entities.Context getContextByUUID​(String uuid)
                                                                                 throws ResourceRegistryException
        Gets the context by UUID.
        Parameters:
        uuid - the uuid
        Returns:
        the context by UUID
        Throws:
        ResourceRegistryException - the resource registry exception

      • getContextByPath

        public org.gcube.informationsystem.contexts.reference.entities.Context getContextByPath​(String contextPath)
                                                                                 throws ResourceRegistryException
        Gets the context by path.
        Parameters:
        contextPath - the context path
        Returns:
        the context by path
        Throws:
        ResourceRegistryException - the resource registry exception

      • getContextsTree

        public org.gcube.informationsystem.dag.Dag<org.gcube.informationsystem.contexts.reference.entities.Context> getContextsTree()
                                                                                                                     throws ResourceRegistryException
        Gets the contexts tree.
        Returns:
        the contexts tree
        Throws:
        ResourceRegistryException - the resource registry exception