package com.sleepycat.bind.serial;
import com.sleepycat.je.DatabaseEntry;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.ForeignKeyNullifier;
import com.sleepycat.je.SecondaryDatabase;
import com.sleepycat.je.SecondaryKeyCreator;
import de.ovgu.cide.jakutil.*;
/**
* A abstract key creator that uses a serial key and a serial data entry. This
* class takes care of serializing and deserializing the key and data entry
* automatically. The following abstract method must be implemented by a
* concrete subclass to create the index key using these objects
* <ul>
* <li> {@link #createSecondaryKey(Object,Object)} </li>
* </ul>
* <!-- begin JE only -->
* <p>
* If {@link com.sleepycat.je.ForeignKeyDeleteAction#NULLIFY} was specified when
* opening the secondary database, the following method must be overridden to
* nullify the foreign index key. If NULLIFY was not specified, this method need
* not be overridden.
* </p>
* <ul>
* <li> {@link #nullifyForeignKey(Object)} </li>
* </ul>
* <!-- end JE only -->
* @author Mark Hayes
*/
public abstract class SerialSerialKeyCreator implements SecondaryKeyCreator, ForeignKeyNullifier {
protected SerialBinding primaryKeyBinding;
protected SerialBinding dataBinding;
protected SerialBinding indexKeyBinding;
/**
* Creates a serial-serial key creator.
* @param classCatalogis the catalog to hold shared class information and for a
* database should be a {@link StoredClassCatalog}.
* @param primaryKeyClassis the primary key base class.
* @param dataClassis the data base class.
* @param indexKeyClassis the index key base class.
*/
public SerialSerialKeyCreator( ClassCatalog classCatalog, Class primaryKeyClass, Class dataClass, Class indexKeyClass){
this(new SerialBinding(classCatalog,primaryKeyClass),new SerialBinding(classCatalog,dataClass),new SerialBinding(classCatalog,indexKeyClass));
}
/**
* Creates a serial-serial entity binding.
* @param primaryKeyBindingis the primary key binding.
* @param dataBindingis the data binding.
* @param indexKeyBindingis the index key binding.
*/
public SerialSerialKeyCreator( SerialBinding primaryKeyBinding, SerialBinding dataBinding, SerialBinding indexKeyBinding){
this.primaryKeyBinding=primaryKeyBinding;
this.dataBinding=dataBinding;
this.indexKeyBinding=indexKeyBinding;
}
public boolean createSecondaryKey( SecondaryDatabase db, DatabaseEntry primaryKeyEntry, DatabaseEntry dataEntry, DatabaseEntry indexKeyEntry) throws DatabaseException {
Object primaryKeyInput=primaryKeyBinding.entryToObject(primaryKeyEntry);
Object dataInput=dataBinding.entryToObject(dataEntry);
Object indexKey=createSecondaryKey(primaryKeyInput,dataInput);
if (indexKey != null) {
indexKeyBinding.objectToEntry(indexKey,indexKeyEntry);
return true;
}
else {
return false;
}
}
public boolean nullifyForeignKey( SecondaryDatabase db, DatabaseEntry dataEntry) throws DatabaseException {
Object data=dataBinding.entryToObject(dataEntry);
data=nullifyForeignKey(data);
if (data != null) {
dataBinding.objectToEntry(data,dataEntry);
return true;
}
else {
return false;
}
}
/**
* Creates the index key object from primary key and entry objects.
* @param primaryKeyis the deserialized source primary key entry, or null if no
* primary key entry is used to construct the index key.
* @param datais the deserialized source data entry, or null if no data
* entry is used to construct the index key.
* @return the destination index key object, or null to indicate that the
* key is not present.
*/
public abstract Object createSecondaryKey( Object primaryKey, Object data);
/**
* Clears the index key in a data object.
* <p>
* On entry the data parameter contains the index key to be cleared. It
* should be changed by this method such that {@link #createSecondaryKey}will return false. Other fields in the data object should remain
* unchanged.
* </p>
* @param datais the source and destination data object.
* @return the destination data object, or null to indicate that the key is
* not present and no change is necessary. The data returned may be
* the same object passed as the data parameter or a newly created
* object.
*/
public Object nullifyForeignKey( Object data){
return null;
}
}