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Berkeley DB Java Edition is a open source, transactional storage solution for Java applications. The Direct Persistence Layer (DPL) API is faster and easier to develop, deploy, and manage than serialized object files or ORM-based Java persistence solutions. The Collections API enhances the standard java.util.collections classes allowing them to be persisted to a local file system and accessed concurrently while protected by ACID transactions. Data is stored by serializing objects and managing class and instance data separately so as not to waste space. Berkeley DB Java Edition is the reliable drop-in solution for complex, fast, and scalable storage. Source for this release is in 'je-4.0.92-sources.jar', the Javadoc is located at 'http://download.oracle.com/berkeley-db/docs/je/4.0.92/'.

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/*-
 * 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.persist;

import java.util.Map;
import java.util.SortedMap;

import com.sleepycat.bind.EntryBinding;
import com.sleepycat.collections.StoredSortedMap;
import com.sleepycat.compat.DbCompat;
import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseEntry;
import com.sleepycat.je.DatabaseException;
/*  */
import com.sleepycat.je.DbInternal;
import com.sleepycat.je.Get;
/*  */
import com.sleepycat.je.LockMode;
/*  */
import com.sleepycat.je.OperationResult;
/*  */
import com.sleepycat.je.OperationStatus;
/*  */
import com.sleepycat.je.ReadOptions;
/*  */
import com.sleepycat.je.Transaction;

/**
 * The EntityIndex returned by SecondaryIndex.keysIndex().  This index maps
 * secondary key to primary key.  In Berkeley DB internal terms, this is a
 * secondary database that is opened without associating it with a primary.
 *
 * @author Mark Hayes
 */
class KeysIndex extends BasicIndex {

    private EntryBinding pkeyBinding;
    private SortedMap map;

    KeysIndex(Database db,
              Class keyClass,
              EntryBinding keyBinding,
              Class pkeyClass,
              EntryBinding pkeyBinding)
        throws DatabaseException {

        super(db, keyClass, keyBinding,
              new DataValueAdapter(pkeyClass, pkeyBinding));
        this.pkeyBinding = pkeyBinding;
    }

    /*
     * Of the EntityIndex methods only get()/map()/sortedMap() are implemented
     * here.  All other methods are implemented by BasicIndex.
     */

    public PK get(SK key)
        throws DatabaseException {

        return get(null, key, null);
    }

    public PK get(Transaction txn, SK key, LockMode lockMode)
        throws DatabaseException {

        /*  */
        if (DbCompat.IS_JE) {
            EntityResult result = get(
                txn, key, Get.SEARCH, DbInternal.getReadOptions(lockMode));
            return result != null ? result.value() : null;
        }
        /*  */

        DatabaseEntry keyEntry = new DatabaseEntry();
        DatabaseEntry pkeyEntry = new DatabaseEntry();
        keyBinding.objectToEntry(key, keyEntry);

        OperationStatus status = db.get(txn, keyEntry, pkeyEntry, lockMode);

        if (status == OperationStatus.SUCCESS) {
            return (PK) pkeyBinding.entryToObject(pkeyEntry);
        } else {
            return null;
        }
    }

    /*  */
    public EntityResult get(Transaction txn,
                                SK key,
                                Get getType,
                                ReadOptions options)
        throws DatabaseException {

        checkGetType(getType);

        DatabaseEntry keyEntry = new DatabaseEntry();
        DatabaseEntry pkeyEntry = new DatabaseEntry();
        keyBinding.objectToEntry(key, keyEntry);

        OperationResult result = db.get(
            txn, keyEntry, pkeyEntry, getType, options);

        if (result != null) {
            return new EntityResult<>(
                (PK) pkeyBinding.entryToObject(pkeyEntry),
                result);
        } else {
            return null;
        }
    }
    /*  */

    public Map map() {
        return sortedMap();
    }

    public synchronized SortedMap sortedMap() {
        if (map == null) {
            map = new StoredSortedMap(db, keyBinding, pkeyBinding, false);
        }
        return map;
    }

    boolean isUpdateAllowed() {
        return false;
    }
}