| /*- |
| * 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.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; |
| } |
| } |