/**
* 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.drill.exec.planner.sql.handlers;
import java.io.IOException;
import java.util.List;
import com.google.common.base.Joiner;
import net.hydromatic.optiq.SchemaPlus;
import net.hydromatic.optiq.tools.RelConversionException;
import net.hydromatic.optiq.tools.ValidationException;
import org.apache.drill.exec.physical.PhysicalPlan;
import org.apache.drill.exec.store.AbstractSchema;
import org.eigenbase.sql.SqlNode;
public abstract class AbstractSqlHandler {
static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(AbstractSqlHandler.class);
public abstract PhysicalPlan getPlan(SqlNode sqlNode) throws ValidationException, RelConversionException, IOException;
public static <T> T unwrap(Object o, Class<T> clazz) throws RelConversionException{
if(clazz.isAssignableFrom(o.getClass())){
return (T) o;
}else{
throw new RelConversionException(String.format("Failure trying to treat %s as type %s.", o.getClass().getSimpleName(), clazz.getSimpleName()));
}
}
/**
* From a given SchemaPlus return a Drill schema object of type AbstractSchema if exists.
* Otherwise throw errors.
*/
public static AbstractSchema getDrillSchema(SchemaPlus schemaPlus) throws Exception{
AbstractSchema drillSchema;
try {
drillSchema = schemaPlus.unwrap(AbstractSchema.class);
drillSchema = drillSchema.getDefaultSchema();
} catch(ClassCastException e) {
throw new Exception("Current schema is not a Drill schema. " +
"Can't create new relations (tables or views) in non-Drill schemas.", e);
}
return drillSchema;
}
/**
* Search for a schema with given schemaPath. First search in schema tree rooted at defaultSchema,
* if not found search in rootSchema. If no schema found throw errors.
*/
public static SchemaPlus findSchema(SchemaPlus rootSchema, SchemaPlus defaultSchema, List<String> schemaPath)
throws Exception {
if (schemaPath.size() == 0)
return defaultSchema;
SchemaPlus schema;
if ((schema = searchSchemaTree(defaultSchema, schemaPath)) != null)
return schema;
if ((schema = searchSchemaTree(rootSchema, schemaPath)) != null)
return schema;
throw new Exception(String.format("Invalid schema path '%s'.", Joiner.on(".").join(schemaPath)));
}
public static boolean isRootSchema(SchemaPlus schema) {
return schema.getParentSchema() == null;
}
private static SchemaPlus searchSchemaTree(SchemaPlus schema, List<String> schemaPath) {
for (String schemaName : schemaPath) {
schema = schema.getSubSchema(schemaName);
if (schema == null) {
return null;
}
}
return schema;
}
}