com.cloudera.impala.analysis.AlterViewStmt.java Source code

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Here is the source code for com.cloudera.impala.analysis.AlterViewStmt.java

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// Copyright 2012 Cloudera Inc.
//
// Licensed 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 com.cloudera.impala.analysis;

import com.cloudera.impala.authorization.Privilege;
import com.cloudera.impala.catalog.Table;
import com.cloudera.impala.catalog.View;
import com.cloudera.impala.common.AnalysisException;
import com.google.common.base.Preconditions;

/**
 * Represents an ALTER VIEW AS statement.
 */
public class AlterViewStmt extends CreateOrAlterViewStmtBase {

    public AlterViewStmt(TableName tableName, QueryStmt viewDefStmt) {
        super(false, tableName, null, null, viewDefStmt);
    }

    @Override
    public void analyze(Analyzer analyzer) throws AnalysisException {
        // Enforce Hive column labels for view compatibility.
        analyzer.setUseHiveColLabels(true);
        viewDefStmt_.analyze(analyzer);

        Preconditions.checkState(tableName_ != null && !tableName_.isEmpty());
        dbName_ = analyzer.getTargetDbName(tableName_);
        owner_ = analyzer.getUser().getName();

        Table table = analyzer.getTable(tableName_, Privilege.ALTER);
        Preconditions.checkNotNull(table);
        if (!(table instanceof View)) {
            throw new AnalysisException(
                    String.format("ALTER VIEW not allowed on a table: %s.%s", dbName_, getTbl()));
        }

        createColumnAndViewDefs(analyzer);
    }

    @Override
    public String toSql() {
        StringBuilder sb = new StringBuilder();
        sb.append("ALTER VIEW ");
        if (tableName_.getDb() != null) {
            sb.append(tableName_.getDb() + ".");
        }
        sb.append(tableName_.getTbl());
        sb.append(" AS " + viewDefStmt_.toSql());
        return sb.toString();
    }
}