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1   /*
2    * Copyright (c) 2010.  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.client.InternalErrorException;
24  import org.apache.expreval.client.NullColumnValueException;
25  import org.apache.expreval.client.ResultMissingColumnException;
26  import org.apache.expreval.expr.ArgumentListTypeSignature;
27  import org.apache.expreval.expr.MultipleExpressionContext;
28  import org.apache.expreval.expr.node.BooleanValue;
29  import org.apache.expreval.expr.node.GenericValue;
30  import org.apache.hadoop.hbase.hbql.client.HBqlException;
31  import org.apache.hadoop.hbase.hbql.impl.HConnectionImpl;
32  import org.apache.hadoop.hbase.hbql.mapping.MappingContext;
33  
34  public class StatementPredicate extends MultipleExpressionContext {
35  
36      private static final ArgumentListTypeSignature typesig = new ArgumentListTypeSignature(BooleanValue.class);
37  
38      public StatementPredicate(final GenericValue... exprs) {
39          super(typesig, exprs);
40      }
41  
42      public boolean useResultData() {
43          return false;
44      }
45  
46      private void validate() throws HBqlException {
47          this.setMappingContext(new MappingContext());
48          this.validateTypes(this.allowColumns(), false);
49      }
50  
51      public boolean evaluate(final HConnectionImpl conn) throws HBqlException {
52  
53          this.validate();
54  
55          try {
56              return (Boolean)this.evaluate(conn, 0, this.allowColumns(), false, conn);
57          }
58          catch (ResultMissingColumnException e) {
59              throw new InternalErrorException("Missing column: " + e.getMessage());
60          }
61          catch (NullColumnValueException e) {
62              throw new InternalErrorException("Null value: " + e.getMessage());
63          }
64      }
65  
66      public String asString() {
67          return "[ " + this.getGenericValue(0).asString() + " ]";
68      }
69  
70      public boolean allowColumns() {
71          return false;
72      }
73  }