org.apache.hadoop.hive.ql.hooks.HookUtils Maven / Gradle / Ivy
/**
* 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.hadoop.hive.ql.hooks;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.hive.common.JavaUtils;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.conf.HiveConf.ConfVars;
import org.apache.hadoop.hive.ql.exec.Utilities;
public class HookUtils {
/**
* Returns the hooks specified in a configuration variable. The hooks are returned
* in a list in the order they were specified in the configuration variable.
*
* @param conf Configuration object
* @param hookConfVar The configuration variable specifying a comma separated list
* of the hook class names.
* @param clazz The super type of the hooks.
* @return A list of the hooks cast as the type specified in clazz,
* in the order they are listed in the value of hookConfVar
* @throws ClassNotFoundException
* @throws IllegalAccessException
* @throws InstantiationException
*/
public static List getHooks(HiveConf conf,
ConfVars hookConfVar, Class clazz)
throws InstantiationException, IllegalAccessException, ClassNotFoundException {
String csHooks = conf.getVar(hookConfVar);
List hooks = new ArrayList();
if (csHooks == null) {
return hooks;
}
csHooks = csHooks.trim();
if (csHooks.equals("")) {
return hooks;
}
String[] hookClasses = csHooks.split(",");
for (String hookClass : hookClasses) {
T hook = (T) Class.forName(hookClass.trim(), true,
Utilities.getSessionSpecifiedClassLoader()).newInstance();
hooks.add(hook);
}
return hooks;
}
}