1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16 package org.apache.commons.jexl.parser;
17
18 import java.lang.reflect.Array;
19 import java.util.Collection;
20 import java.util.Map;
21
22 import org.apache.commons.jexl.JexlContext;
23 import org.apache.commons.jexl.util.Introspector;
24 import org.apache.commons.jexl.util.introspection.Info;
25 import org.apache.commons.jexl.util.introspection.VelMethod;
26
27 /***
28 * generalized size() function for all classes we can think of.
29 *
30 * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
31 * @author <a href="hw@kremvax.net">Mark H. Wilkinson</a>
32 * @version $Id: ASTSizeFunction.java 398324 2006-04-30 12:20:24Z dion $
33 */
34 public class ASTSizeFunction extends SimpleNode {
35 /***
36 * Create the node given an id.
37 *
38 * @param id node id.
39 */
40 public ASTSizeFunction(int id) {
41 super(id);
42 }
43
44 /***
45 * Create a node with the given parser and id.
46 *
47 * @param p a parser.
48 * @param id node id.
49 */
50 public ASTSizeFunction(Parser p, int id) {
51 super(p, id);
52 }
53
54 /*** {@inheritDoc} */
55 public Object jjtAccept(ParserVisitor visitor, Object data) {
56 return visitor.visit(this, data);
57 }
58
59 /*** {@inheritDoc} */
60 public Object value(JexlContext jc) throws Exception {
61 SimpleNode arg = (SimpleNode) jjtGetChild(0);
62
63 Object val = arg.value(jc);
64
65 if (val == null) {
66 throw new Exception("size() : null arg");
67 }
68
69 return new Integer(ASTSizeFunction.sizeOf(val));
70 }
71
72 /***
73 * Calculate the <code>size</code> of various types: Collection, Array, Map, String,
74 * and anything that has a int size() method.
75 *
76 * @param val the object to get the size of.
77 * @return the size of val
78 * @throws Exception if the size cannot be determined.
79 */
80 public static int sizeOf(Object val) throws Exception {
81 if (val instanceof Collection) {
82 return ((Collection) val).size();
83 } else if (val.getClass().isArray()) {
84 return Array.getLength(val);
85 } else if (val instanceof Map) {
86 return ((Map) val).size();
87 } else if (val instanceof String) {
88 return ((String) val).length();
89 } else {
90
91
92
93 Object[] params = new Object[0];
94 Info velInfo = new Info("", 1, 1);
95 VelMethod vm = Introspector.getUberspect().getMethod(val, "size", params, velInfo);
96 if (vm != null && vm.getReturnType() == Integer.TYPE) {
97 Integer result = (Integer) vm.invoke(val, params);
98 return result.intValue();
99 }
100 throw new Exception("size() : unknown type : " + val.getClass());
101 }
102 }
103
104 }