ExternalMetaCache.java

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package org.apache.doris.datasource.metacache;

import org.apache.doris.datasource.SchemaCacheKey;
import org.apache.doris.datasource.SchemaCacheValue;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Optional;

/**
 * Engine-level abstraction for external metadata cache.
 * It defines a unified access path (engine -> catalog -> entry), scoped
 * invalidation APIs, and a common stats output shape.
 */
public interface ExternalMetaCache {
    /**
     * @return engine type name, for example: hive/iceberg/paimon.
     */
    String engine();

    /**
     * Additional engine aliases accepted by the manager.
     */
    Collection<String> aliases();

    /**
     * Initialize all registered entries for one catalog under current engine.
     * Entry instances are created eagerly at this stage.
     *
     * @param catalogId catalog id
     * @param catalogProperties catalog-level properties used for resolving
     *                          entry cache configuration
     */
    void initCatalog(long catalogId, Map<String, String> catalogProperties);

    /**
     * Get one cache entry under an engine and catalog.
     *
     * <p>This is a low-level extension API. Prefer typed engine operations when
     * available.
     */
    <K, V> MetaCacheEntry<K, V> entry(long catalogId, String entryName, Class<K> keyType, Class<V> valueType);

    /**
     * Validate that the catalog has been initialized in current engine cache.
     */
    void checkCatalogInitialized(long catalogId);

    /**
     * Returns whether the catalog is currently initialized in this engine cache.
     */
    boolean isCatalogInitialized(long catalogId);

    /**
     * Typed schema cache access that hides entry-name and class plumbing from callers.
     */
    @SuppressWarnings("unchecked")
    default <K extends SchemaCacheKey> Optional<SchemaCacheValue> getSchemaValue(long catalogId, K key) {
        return Optional.ofNullable(entry(catalogId, "schema", (Class<K>) key.getClass(), SchemaCacheValue.class)
                .get(key));
    }

    /**
     * Invalidate all entries under one catalog in current engine cache.
     */
    void invalidateCatalog(long catalogId);

    /**
     * Invalidate cached data under one catalog but keep the catalog entry group initialized.
     * This is used by refresh flows where catalog lifecycle remains initialized.
     *
     * <p>The default implementation falls back to full catalog invalidation.
     */
    default void invalidateCatalogEntries(long catalogId) {
        invalidateCatalog(catalogId);
    }

    /**
     * Invalidate all entries related to a database.
     */
    void invalidateDb(long catalogId, String dbName);

    /**
     * Invalidate all entries related to a table.
     */
    void invalidateTable(long catalogId, String dbName, String tableName);

    /**
     * Invalidate all entries related to specific partitions.
     */
    void invalidatePartitions(long catalogId, String dbName, String tableName, List<String> partitions);

    /**
     * Return stats of all entries under one catalog.
     */
    Map<String, MetaCacheEntryStats> stats(long catalogId);

    /**
     * Release resources owned by current engine cache.
     */
    void close();
}