/*
 * 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.ddl.view.create;

import org.apache.hadoop.hive.ql.ddl.DDLOperation;
import org.apache.hadoop.hive.ql.ddl.DDLOperationContext;
import org.apache.hadoop.hive.ql.ddl.DDLUtils;
import org.apache.hadoop.hive.ql.hooks.WriteEntity;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.metadata.Table;

/**
 * Operation process of altering a view with a new query.
 */
public class AlterViewAsOperation extends DDLOperation<AlterViewAsDesc> {
  public AlterViewAsOperation(DDLOperationContext context, AlterViewAsDesc desc) {
    super(context, desc);
  }

  @Override
  public int execute() throws HiveException {
    Table oldview = context.getDb().getTable(desc.getViewName(), false);

    // replace existing view
    oldview.setViewOriginalText(desc.getOriginalText());
    oldview.setViewExpandedText(desc.getExpandedText());
    oldview.setFields(desc.getSchema());
    oldview.checkValidity(null);

    context.getDb().alterTable(desc.getViewName(), oldview, false, null, true);
    DDLUtils.addIfAbsentByName(new WriteEntity(oldview, WriteEntity.WriteType.DDL_NO_LOCK),
        context.getWork().getOutputs());

    return 0;
  }
}
