package com.sleepycat.bind.serial;
import com.sleepycat.bind.tuple.TupleBase;
import com.sleepycat.bind.tuple.TupleInput;
import com.sleepycat.bind.tuple.TupleOutput;
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 tuple key and a serial data entry. This
* class takes care of serializing and deserializing the data entry, and
* converting the key entry to/from {@link TupleInput} and {@link TupleOutput}objects. The following abstract method must be implemented by a concrete
* subclass to create the index key using these objects
* <ul>
* <li> {@link #createSecondaryKey(TupleInput,Object,TupleOutput)} </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 TupleSerialKeyCreator extends TupleBase implements SecondaryKeyCreator, ForeignKeyNullifier {
protected SerialBinding dataBinding;
/**
* Creates a tuple-serial key creator.
* @param classCatalogis the catalog to hold shared class information and for a
* database should be a {@link StoredClassCatalog}.
* @param dataClassis the data base class.
*/
public TupleSerialKeyCreator( ClassCatalog classCatalog, Class dataClass){
this(new SerialBinding(classCatalog,dataClass));
}
/**
* Creates a tuple-serial key creator.
* @param dataBindingis the data binding.
*/
public TupleSerialKeyCreator( SerialBinding dataBinding){
this.dataBinding=dataBinding;
}
public boolean createSecondaryKey( SecondaryDatabase db, DatabaseEntry primaryKeyEntry, DatabaseEntry dataEntry, DatabaseEntry indexKeyEntry) throws DatabaseException {
TupleOutput output=getTupleOutput(null);
TupleInput primaryKeyInput=entryToInput(primaryKeyEntry);
Object dataInput=dataBinding.entryToObject(dataEntry);
if (createSecondaryKey(primaryKeyInput,dataInput,output)) {
outputToEntry(output,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 entry from primary key tuple entry and deserialized
* data entry.
* @param primaryKeyInputis the {@link TupleInput} for the primary key entry, or null
* if no primary key entry is used to construct the index key.
* @param dataInputis the deserialized data entry, or null if no data entry is
* used to construct the index key.
* @param indexKeyOutputis the destination index key tuple. For index keys which are
* optionally present, no tuple entry should be output to
* indicate that the key is not present or null.
* @return true if a key was created, or false to indicate that the key is
* not present.
*/
public abstract boolean createSecondaryKey( TupleInput primaryKeyInput, Object dataInput, TupleOutput indexKeyOutput);
/**
* Clears the index key in the deserialized data entry.
* <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 deserialized data entry.
* @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;
}
}