modules/schema/src/main/java/org/apache/ignite/internal/schema/SchemaRegistry.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.ignite.internal.schema;

import java.util.Collection;
import org.apache.ignite.internal.schema.registry.SchemaRegistryException;
import org.apache.ignite.internal.schema.row.Row;

/**
 * Table schema registry interface.
 *
 * <p>Schemas itself MUST be registered in a version ascending order incrementing by {@code 1} with NO gaps, otherwise an exception will be
 * thrown. The version numbering starts from the {@code 1}.
 *
 * <p>After some table maintenance process some first versions may become outdated and can be safely cleaned up if the process guarantees
 * the table no longer has a data of these versions.
 * TODO: IGNITE-16550 Redesign SchemaRegistry to use causality tokens
 *
 * @implSpec The changes in between two arbitrary actual versions MUST NOT be lost. Thus, schema versions can only be removed from the
 *      beginning.
 * @implSpec Initial schema history MAY be registered without the first outdated versions that could be cleaned up earlier.
 */
public interface SchemaRegistry {
    /**
     * Gets schema descriptor for the latest version if initialized.
     *
     * @return Schema descriptor if initialized, {@code null} otherwise.
     */
    SchemaDescriptor schema();

    /**
     * Gets schema descriptor for given version.
     *
     * @param ver Schema version to get descriptor for.
     * @return Schema descriptor of given version.
     * @throws SchemaRegistryException If no schema found for given version.
     */
    SchemaDescriptor schema(int ver) throws SchemaRegistryException;

    /**
     * Gets schema descriptor for the latest version in cluster.
     *
     * @return Schema descriptor if initialized, {@code null} otherwise.
     */
    SchemaDescriptor waitLatestSchema();

    /**
     * Get last registered schema version.
     */
    public int lastSchemaVersion();

    /**
     * Resolve binary row against given schema.
     *
     * @param row  Binary row.
     * @param desc Schema descriptor.
     * @return Schema-aware row.
     */
    Row resolve(BinaryRow row, SchemaDescriptor desc);

    /**
     * Resolve row against the latest schema.
     *
     * @param row Binary row.
     * @return Schema-aware row.
     */
    Row resolve(BinaryRow row);

    /**
     * Resolves batch of binary row against the latest schema.
     *
     * @param rows Binary rows.
     * @return Schema-aware rows.
     */
    Collection<Row> resolve(Collection<BinaryRow> rows);
}