Refactor PreviewHandler (#25941)

* Refactor PreviewHandler * Update
apache · May 30, 2023 · 0f6bb7e · 0f6bb7e
1 parent 618548e
commit 0f6bb7e
Show file tree

Hide file tree

Showing 7 changed files with 52 additions and 163 deletions.
diff --git a/...apache/shardingsphere/proxy/backend/handler/distsql/rul/AbstractSQLRULBackendHandler.java b/...apache/shardingsphere/proxy/backend/handler/distsql/rul/AbstractSQLRULBackendHandler.java
diff --git a/...org/apache/shardingsphere/proxy/backend/handler/distsql/rul/RULBackendHandlerFactory.java b/...org/apache/shardingsphere/proxy/backend/handler/distsql/rul/RULBackendHandlerFactory.java
@@ -19,31 +19,16 @@
 
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
-import org.apache.shardingsphere.distsql.handler.rul.RULExecutor;
 import org.apache.shardingsphere.distsql.parser.statement.rul.RULStatement;
-import org.apache.shardingsphere.distsql.parser.statement.rul.sql.PreviewStatement;
-import org.apache.shardingsphere.infra.util.exception.ShardingSpherePreconditions;
-import org.apache.shardingsphere.infra.util.exception.external.sql.type.generic.UnsupportedSQLOperationException;
-import org.apache.shardingsphere.infra.util.spi.type.typed.TypedSPILoader;
 import org.apache.shardingsphere.proxy.backend.handler.ProxyBackendHandler;
-import org.apache.shardingsphere.proxy.backend.handler.distsql.rul.sql.PreviewHandler;
 import org.apache.shardingsphere.proxy.backend.session.ConnectionSession;
 
-import java.util.HashMap;
-import java.util.Map;
-
 /**
  * RUL backend handler factory.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class RULBackendHandlerFactory {
 
-    private static final Map<Class<? extends RULStatement>, Class<? extends RULBackendHandler<?>>> HANDLERS = new HashMap<>();
-
-    static {
-        HANDLERS.put(PreviewStatement.class, PreviewHandler.class);
-    }
-
     /**
      * Create new instance of RUL backend handler.
      *
@@ -52,26 +37,7 @@ public final class RULBackendHandlerFactory {
      * @return created instance
      */
     public static ProxyBackendHandler newInstance(final RULStatement sqlStatement, final ConnectionSession connectionSession) {
-        if (TypedSPILoader.contains(RULExecutor.class, sqlStatement.getClass().getName())) {
-            RULBackendHandler<?> result = new SQLRULBackendHandler<>();
-            result.init(sqlStatement, connectionSession);
-            return result;
-        }
-        return createRULBackendHandler(sqlStatement, connectionSession);
-    }
-
-    private static RULBackendHandler<?> newInstance(final Class<? extends RULBackendHandler<?>> clazz) {
-        try {
-            return clazz.getDeclaredConstructor().newInstance();
-        } catch (final ReflectiveOperationException ignored) {
-            throw new UnsupportedSQLOperationException(String.format("Can not find public constructor for class `%s`", clazz.getName()));
-        }
-    }
-
-    private static RULBackendHandler<?> createRULBackendHandler(final RULStatement sqlStatement, final ConnectionSession connectionSession) {
-        Class<? extends RULBackendHandler<?>> clazz = HANDLERS.get(sqlStatement.getClass());
-        ShardingSpherePreconditions.checkState(null != clazz, () -> new UnsupportedSQLOperationException(String.format("Unsupported SQL statement : %s", sqlStatement.getClass().getName())));
-        RULBackendHandler<?> result = newInstance(clazz);
+        RULBackendHandler<?> result = new SQLRULBackendHandler<>();
         result.init(sqlStatement, connectionSession);
         return result;
     }

diff --git a/...ava/org/apache/shardingsphere/proxy/backend/handler/distsql/rul/SQLRULBackendHandler.java b/...ava/org/apache/shardingsphere/proxy/backend/handler/distsql/rul/SQLRULBackendHandler.java
@@ -49,7 +49,7 @@ public final class SQLRULBackendHandler<T extends RULStatement> extends RULBacke
     private MergedResult mergedResult;
 
     @Override
-    public ResponseHeader execute() {
+    public ResponseHeader execute() throws SQLException {
         RULExecutor<T> executor = TypedSPILoader.getService(RULExecutor.class, getSqlStatement().getClass().getName());
         queryHeaders = createQueryHeader(executor);
         mergedResult = createMergedResult(executor);
@@ -60,7 +60,7 @@ private List<QueryHeader> createQueryHeader(final RULExecutor<T> executor) {
         return executor.getColumnNames().stream().map(each -> new QueryHeader("", "", each, each, Types.CHAR, "CHAR", 255, 0, false, false, false, false)).collect(Collectors.toList());
     }
 
-    private MergedResult createMergedResult(final RULExecutor<T> executor) {
+    private MergedResult createMergedResult(final RULExecutor<T> executor) throws SQLException {
         if (executor instanceof ConnectionSessionRequiredRULExecutor) {
             ShardingSphereMetaData metaData = ProxyContext.getInstance().getContextManager().getMetaDataContexts().getMetaData();
             return new LocalDataMergedResult(((ConnectionSessionRequiredRULExecutor<T>) executor).getRows(metaData, getConnectionSession(), getSqlStatement()));

diff --git a/...here/proxy/backend/handler/distsql/rul/executor/ConnectionSessionRequiredRULExecutor.java b/...here/proxy/backend/handler/distsql/rul/executor/ConnectionSessionRequiredRULExecutor.java
@@ -23,6 +23,7 @@
 import org.apache.shardingsphere.infra.metadata.ShardingSphereMetaData;
 import org.apache.shardingsphere.proxy.backend.session.ConnectionSession;
 
+import java.sql.SQLException;
 import java.util.Collection;
 
 /**
@@ -39,6 +40,7 @@ public interface ConnectionSessionRequiredRULExecutor<T extends RULStatement> ex
      * @param connectionSession connectionSession connection session
      * @param sqlStatement SQL statement
      * @return query result rows
+     * @throws SQLException SQL exception
      */
-    Collection<LocalDataQueryResultRow> getRows(ShardingSphereMetaData metaData, ConnectionSession connectionSession, T sqlStatement);
+    Collection<LocalDataQueryResultRow> getRows(ShardingSphereMetaData metaData, ConnectionSession connectionSession, T sqlStatement) throws SQLException;
 }