org.springframework.cache.annotation

Annotation Type Cacheable



  • @Target(value={METHOD,TYPE})
     @Retention(value=RUNTIME)
     @Inherited
     @Documented
    public @interface Cacheable
    Annotation indicating that the result of invoking a method (or all methods in a class) can be cached.

    Each time an advised method is invoked, caching behavior will be applied, checking whether the method has been already invoked for the given arguments. A sensible default simply uses the method parameters to compute the key, but a SpEL expression can be provided via the key() attribute, or a custom KeyGenerator implementation can replace the default one (see keyGenerator()).

    If no value is found in the cache for the computed key, the target method will be invoked and the returned value stored in the associated cache. Note that Java8's Optional return types are automatically handled and its content is stored in the cache if present.

    This annotation may be used as a meta-annotation to create custom composed annotations with attribute overrides.

    Since:
    3.1
    Author:
    Costin Leau, Phillip Webb, Stephane Nicoll, Sam Brannen
    See Also:
    CacheConfig
    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element and Description
      java.lang.String cacheManager
      The bean name of the custom CacheManager to use to create a default CacheResolver if none is set already.
      java.lang.String[] cacheNames
      Names of the caches in which method invocation results are stored.
      java.lang.String cacheResolver
      The bean name of the custom CacheResolver to use.
      java.lang.String condition
      Spring Expression Language (SpEL) expression used for making the method caching conditional.
      java.lang.String key
      Spring Expression Language (SpEL) expression for computing the key dynamically.
      java.lang.String keyGenerator
      The bean name of the custom KeyGenerator to use.
      boolean sync
      Synchronize the invocation of the underlying method if several threads are attempting to load a value for the same key.
      java.lang.String unless
      Spring Expression Language (SpEL) expression used to veto method caching.
      java.lang.String[] value
      Alias for cacheNames().
      • cacheNames

        @AliasFor(value="value")
        public abstract java.lang.String[] cacheNames
        Names of the caches in which method invocation results are stored.

        Names may be used to determine the target cache (or caches), matching the qualifier value or bean name of a specific bean definition.

        Since:
        4.2
        See Also:
        value(), CacheConfig.cacheNames()
        Default:
        {}
      • key

        public abstract java.lang.String key
        Spring Expression Language (SpEL) expression for computing the key dynamically.

        Default is "", meaning all method parameters are considered as a key, unless a custom keyGenerator() has been configured.

        The SpEL expression evaluates against a dedicated context that provides the following meta-data:

        • #root.method, #root.target, and #root.caches for references to the method, target object, and affected cache(s) respectively.
        • Shortcuts for the method name (#root.methodName) and target class (#root.targetClass) are also available.
        • Method arguments can be accessed by index. For instance the second argument can be accessed via #root.args[1], #p1 or #a1. Arguments can also be accessed by name if that information is available.
        Default:
        ""
      • condition

        public abstract java.lang.String condition
        Spring Expression Language (SpEL) expression used for making the method caching conditional.

        Default is "", meaning the method result is always cached.

        The SpEL expression evaluates against a dedicated context that provides the following meta-data:

        • #root.method, #root.target, and #root.caches for references to the method, target object, and affected cache(s) respectively.
        • Shortcuts for the method name (#root.methodName) and target class (#root.targetClass) are also available.
        • Method arguments can be accessed by index. For instance the second argument can be accessed via #root.args[1], #p1 or #a1. Arguments can also be accessed by name if that information is available.
        Default:
        ""
      • unless

        public abstract java.lang.String unless
        Spring Expression Language (SpEL) expression used to veto method caching.

        Unlike condition(), this expression is evaluated after the method has been called and can therefore refer to the result.

        Default is "", meaning that caching is never vetoed.

        The SpEL expression evaluates against a dedicated context that provides the following meta-data:

        • #result for a reference to the result of the method invocation. For supported wrappers such as Optional, #result refers to the actual object, not the wrapper
        • #root.method, #root.target, and #root.caches for references to the method, target object, and affected cache(s) respectively.
        • Shortcuts for the method name (#root.methodName) and target class (#root.targetClass) are also available.
        • Method arguments can be accessed by index. For instance the second argument can be accessed via #root.args[1], #p1 or #a1. Arguments can also be accessed by name if that information is available.
        Since:
        3.2
        Default:
        ""
      • sync

        public abstract boolean sync
        Synchronize the invocation of the underlying method if several threads are attempting to load a value for the same key. The synchronization leads to a couple of limitations:
        1. unless() is not supported
        2. Only one cache may be specified
        3. No other cache-related operation can be combined
        This is effectively a hint and the actual cache provider that you are using may not support it in a synchronized fashion. Check your provider documentation for more details on the actual semantics.
        Since:
        4.3
        See Also:
        Cache.get(Object, Callable)
        Default:
        false