| /*- |
| * Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved. |
| * |
| * This file was distributed by Oracle as part of a version of Oracle Berkeley |
| * DB Java Edition made available at: |
| * |
| * http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html |
| * |
| * Please see the LICENSE file included in the top-level directory of the |
| * appropriate version of Oracle Berkeley DB Java Edition for a copy of the |
| * license and additional information. |
| */ |
| |
| package com.sleepycat.bind.serial; |
| |
| 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 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.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 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; |
| } |
| } |