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*
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package com.jcabi.aspects;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;
/**
* Makes a method response cacheable in memory for some time.
*
* For example, this {@code load()} method loads some data from the network
* and we want it to cache loaded data for 5 seconds (to avoid delays):
*
*
@Cacheable(lifetime = 5, unit = TimeUnit.SECONDS)
* String load(String resource) throws IOException {
* return "something";
* }
*
* You can cache them forever, which means that once calculated and
* cached value will never expire (may be a nice alternative to static
* initializers):
*
*
@Cacheable(forever = true)
* String load(String resource) throws IOException {
* return "something";
* }
*
* Since version 0.7.14 you can also annotate methods that should flush
* cache of the object.
*
*
Since 0.7.18 you can control when exactly flushing happens, with
* {@link Cacheable.FlushBefore} and {@link Cacheable.FlushAfter} annotations
* ({@link Cacheable.Flush} is deprecated), for example:
*
*
public class Page {
* @Cacheable
* public String get() {
* // load data from external source, e.g. the network
* return data;
* }
* @Cacheable.FlushBefore
* public void set(String data) {
* // save data to the network
* }
* }
*
* @since 0.7.7
* @see http://aspects.jcabi.com/
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Cacheable {
/**
* Lifetime of an object in cache, in time units.
* @return The time amount
*/
int lifetime() default 1;
/**
* Time units of object lifetime.
*
* The minimum unit you can use is a second. We simply can't cache for
* less than a second, because cache is being cleaned every second.
* @return The time unit
*/
TimeUnit unit() default TimeUnit.MINUTES;
/**
* Keep in cache forever.
* @return The flag
*/
boolean forever() default false;
/**
* Returns the current store after the expiration, and
* then asynchronously update the data.
* @return The flag
*/
boolean asyncUpdate() default false;
/**
* Before-flushing trigger(s).
*
*
Before calling the method, call static method {@code flushBefore()}
* in this class and, according to its result, either flush or not.
* For example:
*
*
class Foo {
* @Cacheable(before = Foo.class)
* int read() {
* // return some number
* }
* public static boolean flushBefore() {
* // if TRUE is returned, flushing will happen before
* // the call to #read()
* }
* }
*
* @since 0.21
* @return The array of types
*/
Class[] before() default { };
/**
* After-flushing trigger(s).
*
* After calling the method, call static method {@code flushAfter()}
* in this class and, according to its result, either flush or not.
* For example:
*
*
class Foo {
* @Cacheable(after = Foo.class)
* int read() {
* // return some number
* }
* public static boolean flushAfter() {
* // if TRUE is returned, flushing will happen after
* // the call to #read()
* }
* }
*
* @since 0.21
* @return The array of types
*/
Class[] after() default { };
/**
* Identifies a method that should flush all cached entities of
* this class/object.
* @since 0.7.14
* @deprecated It is identical to {@link Cacheable.FlushBefore}
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Deprecated
@interface Flush {
}
/**
* Identifies a method that should flush all cached entities of
* this class/object, before being executed.
* @since 0.7.18
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@interface FlushBefore {
}
/**
* Identifies a method that should flush all cached entities of
* this class/object, after being executed.
* @since 0.7.18
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@interface FlushAfter {
}
}