/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2000-2010 Oracle. All rights reserved.
*
*/
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.ForeignKeyNullifier;
import com.sleepycat.je.SecondaryDatabase;
import com.sleepycat.je.SecondaryKeyCreator;
/**
* 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>
* <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>
*
* @see <a href="SerialBinding.html#evolution">Class Evolution</a>
*
* @author Mark Hayes
*/
public abstract class TupleSerialKeyCreator<D> extends TupleBase
implements SecondaryKeyCreator, ForeignKeyNullifier {
protected SerialBinding<D> dataBinding;
/**
* Creates a tuple-serial key creator.
*
* @param classCatalog is the catalog to hold shared class information and
* for a database should be a {@link StoredClassCatalog}.
*
* @param dataClass is the data base class.
*/
public TupleSerialKeyCreator(ClassCatalog classCatalog,
Class<D> dataClass) {
this(new SerialBinding<D>(classCatalog, dataClass));
}
/**
* Creates a tuple-serial key creator.
*
* @param dataBinding is the data binding.
*/
public TupleSerialKeyCreator(SerialBinding<D> dataBinding) {
this.dataBinding = dataBinding;
}
// javadoc is inherited
public boolean createSecondaryKey(SecondaryDatabase db,
DatabaseEntry primaryKeyEntry,
DatabaseEntry dataEntry,
DatabaseEntry indexKeyEntry) {
TupleOutput output = getTupleOutput(null);
TupleInput primaryKeyInput = entryToInput(primaryKeyEntry);
D dataInput = dataBinding.entryToObject(dataEntry);
if (createSecondaryKey(primaryKeyInput, dataInput, output)) {
outputToEntry(output, indexKeyEntry);
return true;
} else {
return false;
}
}
// javadoc is inherited
public boolean nullifyForeignKey(SecondaryDatabase db,
DatabaseEntry dataEntry) {
D 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 primaryKeyInput is the {@link TupleInput} for the primary key
* entry, or null if no primary key entry is used to construct the index
* key.
*
* @param dataInput is the deserialized data entry, or null if no data
* entry is used to construct the index key.
*
* @param indexKeyOutput is 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,
D 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 data is 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 D nullifyForeignKey(D data) {
return null;
}
}