com.google.appengine.api.memcache
Class MemcacheSerialization

java.lang.Object
  com.google.appengine.api.memcache.MemcacheSerialization

public class MemcacheSerialization
extends java.lang.Object

Static serialization helpers shared by MemcacheServiceImpl and com.google.appengine.api.memcache.dev.LocalMemcacheService. This class is thread-safe.

Nested Class Summary

static class	MemcacheSerialization.Flag Values used as flags on the MemcacheService's values.
static class	MemcacheSerialization.ValueAndFlags Tuple of a serialized byte array value and associated flags to interpret that value.

Method Summary

static java.lang.Object	deserialize(byte[] value, int flags) Deserialize the object, according to its flags.
static byte[]	makePbKey(java.lang.Object key) Converts the user's key Object into a byte[] for the MemcacheGetRequest.
static MemcacheSerialization.ValueAndFlags	serialize(java.lang.Object value)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

deserialize

public static java.lang.Object deserialize(byte[] value,
                                           int flags)
                                    throws java.lang.ClassNotFoundException,
                                           java.io.IOException

Deserialize the object, according to its flags. This would have private visibility, but is also used by LocalMemcacheService for the increment operation.

Parameters:

value -

flags -

Returns:

the Object originally stored

Throws:

java.lang.ClassNotFoundException - if the object can't be re-instantiated due to being an unlocatable type

java.io.IOException - if the object can't be re-instantiated for some other reason

makePbKey

public static byte[] makePbKey(java.lang.Object key)
                        throws java.io.IOException

Converts the user's key Object into a byte[] for the MemcacheGetRequest. Because the underlying service has a length limit, we actually use the SHA1 hash of the serialized object as its key if it's not a basic type. For the basic types (that is, String, Boolean, and the fixed-point numbers), we use a human-readable representation.

Parameters:

key -

Returns:

hash result. For the key null, the hash is also null.

Throws:

java.io.IOException

serialize

public static MemcacheSerialization.ValueAndFlags serialize(java.lang.Object value)
                                                     throws java.io.IOException

Parameters:

value -

Returns:

the ValueAndFlags containing a serialized representation of the Object and the flags to hint deserialization.

Throws:

java.io.IOException - for serialization errors, normally due to a non-serializable object type