ExternalMetaCache.java

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package org.apache.doris.datasource.metacache;

import org.apache.doris.connector.metacache.MetaCacheEntry;
import org.apache.doris.connector.metacache.spi.MetaCacheLifecycle;
import org.apache.doris.datasource.SchemaCacheKey;
import org.apache.doris.datasource.SchemaCacheValue;

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 extends MetaCacheLifecycle {
    /**
     * 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);

    /**
     * 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));
    }

}