DialectConverterPlugin.java

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package org.apache.doris.plugin;

import org.apache.doris.analysis.StatementBase;
import org.apache.doris.nereids.parser.Dialect;
import org.apache.doris.qe.SessionVariable;

import com.google.common.collect.ImmutableSet;

import java.util.List;
import javax.annotation.Nullable;

/**
 * Sql dialect adapter interface.
 */
public interface DialectConverterPlugin {

    /**
     * Set dialect set which this plugin can handle
     */
    ImmutableSet<Dialect> acceptDialects();

    /**
     * <pre>
     * Override this method if you want to convert sql before parse.
     * Fallback to next dialect plugin if this method returns null, empty string or any exception throws.
     * If all plugins fail to convert (returns null, empty string or any exception throws),
     * Nereids parser will use the original SQL.
     * </pre>
     * */
    default @Nullable String convertSql(String originSql, SessionVariable sessionVariable) {
        return null;
    }

    /**
     * <pre>
     * Parse sql with dialect.
     * Fallback to next dialect plugin if this method returns null, empty string or any exception throws.
     * If all plugins fail to parse (returns null, empty string or any exception throws),
     * Nereids parser will fallback to invoke {@link org.apache.doris.nereids.parser.NereidsParser#parseSQL(String)}.
     * Use Dialect.getByName(sessionVariable.getSqlDialect()) to extract the dialect parameter.
     * </pre>
     * */
    @Nullable List<StatementBase> parseSqlWithDialect(String sql, SessionVariable sessionVariable);
}