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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2000, 2015 Oracle and/or its affiliates. All rights reserved.
*
*/
package com.sleepycat.bind.serial;
import com.sleepycat.db.DatabaseEntry;
import com.sleepycat.db.ForeignKeyNullifier;
import com.sleepycat.db.SecondaryDatabase;
import com.sleepycat.db.SecondaryKeyCreator;
/**
* 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>
* <p>If {@link com.sleepycat.db.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 SerialSerialKeyCreator<PK,D,SK>
implements SecondaryKeyCreator, ForeignKeyNullifier {
protected SerialBinding<PK> primaryKeyBinding;
protected SerialBinding<D> dataBinding;
protected SerialBinding<SK> indexKeyBinding;
/**
* Creates a serial-serial key creator.
*
* @param classCatalog is the catalog to hold shared class information and
* for a database should be a {@link StoredClassCatalog}.
*
* @param primaryKeyClass is the primary key base class.
*
* @param dataClass is the data base class.
*
* @param indexKeyClass is the index key base class.
*/
public SerialSerialKeyCreator(ClassCatalog classCatalog,
Class<PK> primaryKeyClass,
Class<D> dataClass,
Class<SK> indexKeyClass) {
this(new SerialBinding<PK>(classCatalog, primaryKeyClass),
new SerialBinding<D>(classCatalog, dataClass),
new SerialBinding<SK>(classCatalog, indexKeyClass));
}
/**
* Creates a serial-serial entity binding.
*
* @param primaryKeyBinding is the primary key binding.
*
* @param dataBinding is the data binding.
*
* @param indexKeyBinding is the index key binding.
*/
public SerialSerialKeyCreator(SerialBinding<PK> primaryKeyBinding,
SerialBinding<D> dataBinding,
SerialBinding<SK> indexKeyBinding) {
this.primaryKeyBinding = primaryKeyBinding;
this.dataBinding = dataBinding;
this.indexKeyBinding = indexKeyBinding;
}
// javadoc is inherited
public boolean createSecondaryKey(SecondaryDatabase db,
DatabaseEntry primaryKeyEntry,
DatabaseEntry dataEntry,
DatabaseEntry indexKeyEntry) {
PK primaryKeyInput =
primaryKeyBinding.entryToObject(primaryKeyEntry);
D dataInput = dataBinding.entryToObject(dataEntry);
SK indexKey = createSecondaryKey(primaryKeyInput, dataInput);
if (indexKey != null) {
indexKeyBinding.objectToEntry(indexKey, 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 object from primary key and data objects.
*
* @param primaryKey is the deserialized source primary key entry, or
* null if no primary key entry is used to construct the index key.
*
* @param data is 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 SK createSecondaryKey(PK primaryKey, D 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 data is 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 D nullifyForeignKey(D data) {
return null;
}
}
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