com.sleepycat.bind.serial

Class SerialBinding

public class SerialBinding extends SerialBase implements EntryBinding

A concrete EntryBinding that treats a key or data entry as a serialized object.

This binding stores objects in serialized object format. The deserialized objects are returned by the binding, and their Class must implement the Serializable interface.

For key bindings, a tuple binding is usually a better choice than a serial binding. A tuple binding gives a reasonable sort order, and works with comparators in all cases -- see below.

WARNING: SerialBinding should not be used with Berkeley DB Java Edition for key bindings, when a custom comparator is used. In JE, comparators are instantiated and called internally at times when databases are not accessible. Because serial bindings depend on the class catalog database, a serial binding cannot be used during these times. An attempt to use a serial binding with a custom comparator will result in a NullPointerException during environment open or close.

Constructor Summary
SerialBinding(ClassCatalog classCatalog, Class baseClass)
Creates a serial binding.
Method Summary
ObjectentryToObject(DatabaseEntry entry)
Deserialize an object from an entry buffer.
ClassgetBaseClass()
Returns the base class for this binding.
ClassLoadergetClassLoader()
Returns the class loader to be used during deserialization, or null if a default class loader should be used.
voidobjectToEntry(Object object, DatabaseEntry entry)
Serialize an object into an entry buffer.

Constructor Detail

SerialBinding

public SerialBinding(ClassCatalog classCatalog, Class baseClass)
Creates a serial binding.

Parameters: classCatalog is the catalog to hold shared class information and for a database should be a StoredClassCatalog. baseClass is the base class for serialized objects stored using this binding -- all objects using this binding must be an instance of this class.

Method Detail

entryToObject

public Object entryToObject(DatabaseEntry entry)
Deserialize an object from an entry buffer. May only be called for data that was serialized using SerialBinding, since the fixed serialization header is assumed to not be included in the input data. SerialInput is used to deserialize the object.

Parameters: entry is the input serialized entry.

Returns: the output deserialized object.

getBaseClass

public final Class getBaseClass()
Returns the base class for this binding.

Returns: the base class for this binding.

getClassLoader

public ClassLoader getClassLoader()
Returns the class loader to be used during deserialization, or null if a default class loader should be used. The default implementation of this method returns null.

This method may be overriden to return a dynamically determined class loader. For example, Thread.currentThread().getContextClassLoader() could be called to use the context class loader for the curren thread. Or getBaseClass().getClassLoader() could be called to use the class loader for the base class, assuming that a base class has been specified.

If this method returns null, a default class loader will be used as determined by the java.io.ObjectInputStream.resolveClass method.

objectToEntry

public void objectToEntry(Object object, DatabaseEntry entry)
Serialize an object into an entry buffer. The fixed serialization header is not included in the output data to save space, and therefore to deserialize the data the complementary SerialBinding method must be used. SerialOutput is used to serialize the object.

Note that this method sets the DatabaseEntry offset property to a non-zero value and the size property to a value less than the length of the byte array.

Parameters: object is the input deserialized object. entry is the output serialized entry.

Throws: IllegalArgumentException if the object is not an instance of the base class for this binding.