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1 package fr.improve.struts.taglib.layout.el;
2
3 import java.util.ArrayList  ;
4 import java.util.Iterator ;
5 import java.util.List ;
6 import java.util.WeakHashMap ;
7
8 import javax.servlet.jsp.PageContext ;
9
10 import fr.improve.struts.taglib.layout.skin.Skin;
11 import fr.improve.struts.taglib.layout.util.LayoutUtils;
12
13
18 public class Expression {
19
20
21
22
25 private static WeakHashMap cache = new WeakHashMap ();
26
27
30 public static String evaluate(String in_string, PageContext in_pg) throws EvaluationException {
31 if (in_string==null) {
32 return null;
33 }
34 Skin skin = LayoutUtils.getSkin(in_pg.getSession());
35 String elDelim = skin.getELCharacter() + "{";
36 if (in_string.indexOf(elDelim)==-1) {
37 return in_string;
38 }
39
40 Expression lc_expr = (Expression) cache.get(in_string);
42 if (lc_expr==null) {
43 lc_expr = new Expression(in_string, elDelim);
44 cache.put(in_string, lc_expr);
45 }
46
47 return lc_expr.evalueExpression(in_pg);
48 }
49
50
53 private List blocks = new ArrayList ();
54
55
58 private Expression(String in_string, String in_delim) throws EvaluationException {
59 int lc_beginIndex = -1;
60 int lc_endIndex = -1;
61 String lc_string = in_string;
62 lc_beginIndex = lc_string.indexOf(in_delim);
63 while (lc_beginIndex!=-1) {
64 lc_endIndex = lc_string.indexOf('}', lc_beginIndex);
66 if (lc_endIndex==-1) {
67 throw new EvaluationException("Invalid expression " + in_string);
68 }
69
70 if (lc_beginIndex>0) {
72 blocks.add(new TextBlock(lc_string.substring(0, lc_beginIndex)));
73 }
74
75 int lc_nestedVar = lc_string.indexOf(in_delim, lc_beginIndex+2);
77 if (lc_nestedVar>lc_beginIndex && lc_nestedVar<lc_endIndex) {
78 lc_endIndex = lc_string.indexOf('}', lc_endIndex+1);
80 }
81
82 String lc_variable = lc_string.substring(lc_beginIndex+2, lc_endIndex);
84 int lc_delim = lc_variable.indexOf('.');
85 if (lc_delim==-1) {
86 blocks.add(parseBlock(lc_variable, null));
87 } else {
88 blocks.add(parseBlock(lc_variable.substring(0,lc_delim), lc_variable.substring(lc_delim+1)));
89 }
90
91
92 lc_string = lc_string.substring(lc_endIndex+1);
94 lc_beginIndex = lc_string.indexOf(in_delim);
95 lc_endIndex = -1;
96
97
98 }
99
100 if (lc_string!=null) {
102 blocks.add(new TextBlock(lc_string));
103 }
104 }
105
106 private Block parseBlock(String in_name, String in_property) {
107 if (in_name!=null) {
108 int position = in_name.indexOf('+');
109 if (position!=-1) {
110 String left = in_name.substring(0, position);
111 String right = in_name.substring(position+1);
112 VarBlock var1 = new VarBlock(left, null);
113 TextBlock var2 = new TextBlock(right);
114 return new AddBlock(var1, var2);
115 }
116 }
117 return new VarBlock(in_name, in_property);
118 }
119
120 private String evalueExpression(PageContext in_pg) throws EvaluationException {
121 StringBuffer lc_buffer = new StringBuffer (10 * blocks.size());
122 Iterator lc_it = blocks.iterator();
123 while (lc_it.hasNext()) {
124 Block lc_block = (Block) lc_it.next();
125 lc_buffer.append(lc_block.evaluate(in_pg));
126 }
127 return lc_buffer.toString();
128 }
129
130 public String toString() {
131 StringBuffer buffer = new StringBuffer ();
132 Iterator it = blocks.iterator();
133 while (it.hasNext()) {
134 Block block = (Block) it.next();
135 buffer.append(block.toString());
136 buffer.append(" ");
137 }
138 return buffer.toString();
139 }
140
141 public static void main(String argv[]) {
142 Expression lc_expr = new Expression("${personnes[${idPersonne}].qualite}", "${");
143 System.out.println(lc_expr);
144
145 lc_expr = new Expression("${name}", "${");
146 System.out.println(lc_expr);
147
148 lc_expr = new Expression("${name.property}", "${");
149 System.out.println(lc_expr);
150
151 lc_expr = new Expression("abc${name}def", "${");
152 System.out.println(lc_expr);
153
154 lc_expr = new Expression("${index+1}", "${");
155 System.out.println(lc_expr);
156 }
157 }
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