01: /*
02: * $Id: TableColumnsUsedInFunctionVisitor.java,v 1.4 2005/12/20 18:32:27 ahimanikya Exp $
03: * =======================================================================
04: * Copyright (c) 2004 Axion Development Team. All rights reserved.
05: *
06: * Redistribution and use in source and binary forms, with or without
07: * modification, are permitted provided that the following conditions
08: * are met:
09: *
10: * 1. Redistributions of source code must retain the above
11: * copyright notice, this list of conditions and the following
12: * disclaimer.
13: *
14: * 2. Redistributions in binary form must reproduce the above copyright
15: * notice, this list of conditions and the following disclaimer in
16: * the documentation and/or other materials provided with the
17: * distribution.
18: *
19: * 3. The names "Tigris", "Axion", nor the names of its contributors may
20: * not be used to endorse or promote products derived from this
21: * software without specific prior written permission.
22: *
23: * 4. Products derived from this software may not be called "Axion", nor
24: * may "Tigris" or "Axion" appear in their names without specific prior
25: * written permission.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
30: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38: * =======================================================================
39: */
40:
41: package org.axiondb.engine.visitors;
42:
43: import java.util.HashSet;
44: import java.util.Set;
45:
46: import org.axiondb.AxionException;
47: import org.axiondb.ColumnIdentifier;
48: import org.axiondb.Function;
49: import org.axiondb.Selectable;
50: import org.axiondb.Table;
51:
52: /**
53: * Returns a set of columns used in a function for a given Table.
54: *
55: * @author Ritesh Adval
56: */
57: public class TableColumnsUsedInFunctionVisitor {
58:
59: private Set columnsUsedInFunction = new HashSet();
60:
61: public Set getColumnsUsedInFunction() {
62: return columnsUsedInFunction;
63: }
64:
65: public void visit(Function fn, Table sourceTable)
66: throws AxionException {
67: for (int i = 0, I = fn.getArgumentCount(); i < I; i++) {
68: Selectable sel = fn.getArgument(i);
69: if (sel instanceof Function) {
70: visit((Function) sel, sourceTable);
71: } else if (sel instanceof ColumnIdentifier) {
72: ColumnIdentifier col = (ColumnIdentifier) sel;
73: String tname = col.getTableIdentifier().getTableName();
74: if (tname.equals(sourceTable.getName())
75: && sourceTable.hasColumn(col)) {
76: columnsUsedInFunction.add(col);
77: }
78: }
79: }
80: }
81: }
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