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1   /*
2    * Copyright (c) 2011.  The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  
21  package org.apache.hadoop.hbase.hbql.statement;
22  
23  import org.apache.expreval.expr.node.GenericValue;
24  import org.apache.hadoop.hbase.hbql.client.ExecutionResults;
25  import org.apache.hadoop.hbase.hbql.client.HBqlException;
26  import org.apache.hadoop.hbase.hbql.impl.HConnectionImpl;
27  import org.apache.hadoop.hbase.hbql.statement.select.SimpleExpressionContext;
28  
29  public class EvalStatement extends GenericStatement implements ConnectionStatement {
30  
31      private final GenericValue genericValue;
32  
33      public EvalStatement(final GenericValue genericValue) {
34          super(null);
35          this.genericValue = genericValue;
36      }
37  
38      private GenericValue getGenericValue() {
39          return this.genericValue;
40      }
41  
42      public ExecutionResults execute(HConnectionImpl connection) throws HBqlException {
43  
44          final ExecutionResults retval = new ExecutionResults("Parsed successfully");
45  
46          if (this.getGenericValue() != null) {
47              final SimpleExpressionContext expr = new SimpleExpressionContext(this.getGenericValue());
48              expr.validate();
49              final Object val = expr.getValue(connection);
50              retval.out.println(this.getGenericValue().asString() + " = " + val);
51          }
52  
53          return retval;
54      }
55  
56      public static String usage() {
57          return "EVAL expression";
58      }
59  }