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Xodus is pure Java transactional schema-less embedded database

There is a newer version: 2.0.1

/**
 * Copyright 2010 - 2018 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package jetbrains.exodus.tree.btree;

import jetbrains.exodus.ByteIterator;
import jetbrains.exodus.env.EnvironmentImpl;
import jetbrains.exodus.log.CompressedUnsignedLongByteIterable;
import jetbrains.exodus.log.Log;
import jetbrains.exodus.tree.TreeMetaInfo;
import org.jetbrains.annotations.NotNull;

public class BTreeMetaInfo extends TreeMetaInfo {

    final BTreeBalancePolicy balancePolicy;

    private BTreeMetaInfo(@NotNull final Log log,
                          @NotNull final BTreeBalancePolicy balancePolicy,
                          final boolean duplicates,
                          final int structureId) {
        super(log, duplicates, structureId);
        this.balancePolicy = balancePolicy;
    }

    public BTreeMetaInfo(@NotNull final EnvironmentImpl env, final boolean duplicates, final int structureId) {
        this(env.getLog(), env.getBTreeBalancePolicy(), duplicates, structureId);
    }

    @Override
    public boolean isKeyPrefixing() {
        return false;
    }

    @Override
    public BTreeMetaInfo clone(final int newStructureId) {
        return new BTreeMetaInfo(log, balancePolicy, duplicates, newStructureId);
    }

    public static BTreeMetaInfo load(@NotNull final EnvironmentImpl env, byte flagsByte, ByteIterator it) {
        final boolean duplicates = (flagsByte & DUPLICATES_BIT) != 0;
        CompressedUnsignedLongByteIterable.getInt(it); // legacy format
        final int structureId = CompressedUnsignedLongByteIterable.getInt(it);
        return new BTreeMetaInfo(env, duplicates, structureId);
    }
}