package play.cache;
import java.io.NotSerializableException;
import java.io.Serializable;
import java.util.Map;
import play.Logger;
import play.Play;
import play.exceptions.CacheException;
import play.libs.Time;
/**
* The Cache. Mainly an interface to memcached or EhCache.
*
* Note: When specifying expiration == "0s" (zero seconds) the actual expiration-time may vary between different cache implementations
*/
public abstract class Cache {
/**
* The underlying cache implementation
*/
public static CacheImpl cacheImpl;
/**
* Sometime we REALLY need to change the implementation :)
*/
public static CacheImpl forcedCacheImpl;
/**
* Add an element only if it doesn't exist.
* @param key Element key
* @param value Element value
* @param expiration Ex: 10s, 3mn, 8h
*/
public static void add(String key, Object value, String expiration) {
checkSerializable(value);
cacheImpl.add(key, value, Time.parseDuration(expiration));
}
/**
* Add an element only if it doesn't exist, and return only when
* the element is effectively cached.
* @param key Element key
* @param value Element value
* @param expiration Ex: 10s, 3mn, 8h
* @return If the element an eventually been cached
*/
public static boolean safeAdd(String key, Object value, String expiration) {
checkSerializable(value);
return cacheImpl.safeAdd(key, value, Time.parseDuration(expiration));
}
/**
* Add an element only if it doesn't exist and store it indefinitely.
* @param key Element key
* @param value Element value
*/
public static void add(String key, Object value) {
checkSerializable(value);
cacheImpl.add(key, value, Time.parseDuration(null));
}
/**
* Set an element.
* @param key Element key
* @param value Element value
* @param expiration Ex: 10s, 3mn, 8h
*/
public static void set(String key, Object value, String expiration) {
checkSerializable(value);
cacheImpl.set(key, value, Time.parseDuration(expiration));
}
/**
* Set an element and return only when the element is effectively cached.
* @param key Element key
* @param value Element value
* @param expiration Ex: 10s, 3mn, 8h
* @return If the element an eventually been cached
*/
public static boolean safeSet(String key, Object value, String expiration) {
checkSerializable(value);
return cacheImpl.safeSet(key, value, Time.parseDuration(expiration));
}
/**
* Set an element and store it indefinitely.
* @param key Element key
* @param value Element value
*/
public static void set(String key, Object value) {
checkSerializable(value);
cacheImpl.set(key, value, Time.parseDuration(null));
}
/**
* Replace an element only if it already exists.
* @param key Element key
* @param value Element value
* @param expiration Ex: 10s, 3mn, 8h
*/
public static void replace(String key, Object value, String expiration) {
checkSerializable(value);
cacheImpl.replace(key, value, Time.parseDuration(expiration));
}
/**
* Replace an element only if it already exists and return only when the
* element is effectively cached.
* @param key Element key
* @param value Element value
* @param expiration Ex: 10s, 3mn, 8h
* @return If the element an eventually been cached
*/
public static boolean safeReplace(String key, Object value, String expiration) {
checkSerializable(value);
return cacheImpl.safeReplace(key, value, Time.parseDuration(expiration));
}
/**
* Replace an element only if it already exists and store it indefinitely.
* @param key Element key
* @param value Element value
*/
public static void replace(String key, Object value) {
checkSerializable(value);
cacheImpl.replace(key, value, Time.parseDuration(null));
}
/**
* Increment the element value (must be a Number).
* @param key Element key
* @param by The incr value
* @return The new value
*/
public static long incr(String key, int by) {
return cacheImpl.incr(key, by);
}
/**
* Increment the element value (must be a Number) by 1.
* @param key Element key
* @return The new value
*/
public static long incr(String key) {
return cacheImpl.incr(key, 1);
}
/**
* Decrement the element value (must be a Number).
* @param key Element key
* @param by The decr value
* @return The new value
*/
public static long decr(String key, int by) {
return cacheImpl.decr(key, by);
}
/**
* Decrement the element value (must be a Number) by 1.
* @param key Element key
* @return The new value
*/
public static long decr(String key) {
return cacheImpl.decr(key, 1);
}
/**
* Retrieve an object.
* @param key The element key
* @return The element value or null
*/
public static Object get(String key) {
return cacheImpl.get(key);
}
/**
* Bulk retrieve.
* @param key List of keys
* @return Map of keys & values
*/
public static Map<String, Object> get(String... key) {
return cacheImpl.get(key);
}
/**
* Delete an element from the cache.
* @param key The element key
*/
public static void delete(String key) {
cacheImpl.delete(key);
}
/**
* Delete an element from the cache and return only when the
* element is effectively removed.
* @param key The element key
* @return If the element an eventually been deleted
*/
public static boolean safeDelete(String key) {
return cacheImpl.safeDelete(key);
}
/**
* Clear all data from cache.
*/
public static void clear() {
cacheImpl.clear();
}
/**
* Convenient clazz to get a value a class type;
* @param <T> The needed type
* @param key The element key
* @param clazz The type class
* @return The element value or null
*/
@SuppressWarnings("unchecked")
public static <T> T get(String key, Class<T> clazz) {
return (T) cacheImpl.get(key);
}
/**
* Initialize the cache system.
*/
public static void init() {
if(forcedCacheImpl != null) {
cacheImpl = forcedCacheImpl;
return;
}
if (Play.configuration.getProperty("memcached", "disabled").equals("enabled")) {
try {
cacheImpl = MemcachedImpl.getInstance(true);
Logger.info("Connected to memcached");
} catch (Exception e) {
Logger.error(e, "Error while connecting to memcached");
Logger.warn("Fallback to local cache");
cacheImpl = EhCacheImpl.getInstance();
}
} else {
cacheImpl = EhCacheImpl.newInstance();
}
}
/**
* Stop the cache system.
*/
public static void stop() {
cacheImpl.stop();
}
/**
* Utility that check that an object is serializable.
*/
static void checkSerializable(Object value) {
if(value != null && !(value instanceof Serializable)) {
throw new CacheException("Cannot cache a non-serializable value of type " + value.getClass().getName(), new NotSerializableException(value.getClass().getName()));
}
}
}