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1
18 package org.apache.beehive.netui.script.el;
19
20 import org.apache.beehive.netui.util.internal.InternalStringBuilder;
21
22 import java.util.ArrayList  ;
23 import java.util.Collections ;
24 import java.util.Iterator ;
25 import java.util.List ;
26
27 import org.apache.beehive.netui.script.Expression;
28 import org.apache.beehive.netui.script.el.tokens.ArrayIndexToken;
29 import org.apache.beehive.netui.script.el.tokens.ContextToken;
30 import org.apache.beehive.netui.script.el.tokens.ExpressionToken;
31 import org.apache.beehive.netui.script.el.tokens.IdentifierToken;
32 import org.apache.beehive.netui.script.el.tokens.MapKeyToken;
33 import org.apache.beehive.netui.script.el.util.BindingContext;
34 import org.apache.beehive.netui.script.el.util.ParseUtils;
35 import org.apache.beehive.netui.util.logging.Logger;
36
37
40 public class ExpressionTerm
41 extends Expression
42 implements Term {
43
44 private static Logger LOGGER = Logger.getInstance(ExpressionTerm.class);
45
46 private List _tokens = null;
47 private String _exprStr = null;
48 private ContextToken _context = null;
49 private ExpressionToken[] _tokenArray = null;
50 private List _noModTokens = null;
51
52 public ExpressionTerm() {
53 super();
54 _tokens = new ArrayList ();
55 }
56
57 public void seal() {
58 _context = (ContextToken)_tokens.get(0);
59 _tokenArray = new ExpressionToken[_tokens.size()];
60
61 InternalStringBuilder buf = new InternalStringBuilder();
62 for(int i = 0; i < _tokens.size(); i++) {
63 buf.append(((ExpressionToken)_tokens.get(i)).getTokenString());
64 _tokenArray[i] = (ExpressionToken)_tokens.get(i);
65 }
66
67 _exprStr = buf.toString();
68
69 _noModTokens = Collections.unmodifiableList(_tokens);
70 }
71
72 public String getContext() {
73 return _context.getName();
74 }
75
76 public List getTokens() {
77 return _noModTokens;
78 }
79
80 public String getExpression(int start) {
81 if(start >= _tokens.size())
82 throw new IllegalStateException ("The index \"" + start + "\" is an invalid reference into an expression with \"" +
83 _tokens.size() + "\" _tokens.");
84
85 boolean needDot = true;
86 InternalStringBuilder buf = new InternalStringBuilder();
87 buf.append("{");
88 for(int i = start; i < _tokens.size(); i++) {
89 ExpressionToken tok = (ExpressionToken)_tokens.get(i);
90 if(tok instanceof ArrayIndexToken) {
91 buf.append(tok.getTokenString());
92 needDot = false;
93 } else if(tok instanceof IdentifierToken) {
94 if(needDot && i != start) buf.append(".");
95 buf.append(tok.toString());
96 needDot = true;
97 } else if(tok instanceof MapKeyToken) {
98 buf.append(tok.getTokenString());
99 needDot = false;
100 }
101 }
102 buf.append("}");
103 return buf.toString();
104 }
105
106 public void addToken(ExpressionToken token) {
107 _tokens.add(token);
108 }
109
110 public Iterator getExpressionTokens() {
111 return _tokens.iterator();
112 }
113
114 public int getTokenCount() {
115 return _tokenArray.length;
116 }
117
118 public ExpressionToken getToken(int index) {
119 return _tokenArray[index];
121 }
122
123 public String getExpressionString() {
124 return _exprStr;
125 }
126
127 public Object evaluate(NetUIVariableResolver vr) {
128 return _evaluate(_tokens.size(), vr);
129 }
130
131 public void update(Object newValue, NetUIVariableResolver vr) {
132 Object branch = _evaluate(_tokens.size() - 1, vr);
134
135 ExpressionToken token = _tokenArray[_tokens.size() - 1];
136
137 if(LOGGER.isDebugEnabled()) LOGGER.debug("Update leaf token: " + token + " on object: " + branch);
138
139 token.update(branch, newValue);
141 }
142
143
144 public String changeContext(String oldContext, String newContext, Object index) {
145 String thisExpr = getExpressionString();
146
147 if(LOGGER.isDebugEnabled()) LOGGER.debug("oldContext: " + oldContext + " newContext: " + newContext + " thisExpr: " + thisExpr);
148
149 ParsedExpression pe = ParseUtils.parse(newContext);
151
152 if(!pe.isExpression()) {
153 String msg = "The expression can not be qualified into new _context because the new _context is not atomic.";
154 if(LOGGER.isErrorEnabled()) LOGGER.error(msg);
155 throw new RuntimeException (msg);
156 }
157
158 if(!thisExpr.startsWith(oldContext)) {
160 return "{" + thisExpr + "}";
161 }
162
163 if(index instanceof Integer && ((Integer )index).intValue() > 32767) {
164 String msg = "Can not create an indexed expression with an array index greater than the Java array limit for the expression \"" +
165 thisExpr + "\"";
166
167 if(LOGGER.isWarnEnabled()) LOGGER.warn(msg);
168 throw new RuntimeException (msg);
169 }
170
171 String ctxStr = pe.getExpressionString();
172
173 ctxStr = ctxStr + "[" + index + "]";
174
175 if(LOGGER.isDebugEnabled()) LOGGER.debug("thisExpr: " + thisExpr + " ctxStr: " + ctxStr);
176
177 thisExpr = thisExpr.replaceFirst(oldContext, ctxStr);
178
179 InternalStringBuilder buf = new InternalStringBuilder();
180 buf.append("{");
181 buf.append(thisExpr);
182 buf.append("}");
183
184 return buf.toString();
185 }
186
187 public String qualify(String contextName) {
188 InternalStringBuilder buf = new InternalStringBuilder();
189 buf.append("{");
190 buf.append(contextName);
191 buf.append(".");
192 buf.append(getExpressionString());
193 buf.append("}");
194
195 return buf.toString();
196 }
197
198 public String toString() {
199 InternalStringBuilder buf = new InternalStringBuilder();
200 buf.append("ExpressionTerm:\n");
201 for(int i = 0; i < _tokens.size(); i++) {
202 buf.append(" " + _tokens.get(i).toString() + "\n");
203 }
204 return buf.toString();
205 }
206
207 private final Object _evaluate(int index, NetUIVariableResolver vr) {
208 Object result = null;
209
210 if(_tokens.size() == 1) {
211 if(LOGGER.isDebugEnabled()) LOGGER.debug("found single term expression");
212
213 result = vr.resolveVariable(_context.getName());
214
215 if(result != null && result instanceof BindingContext) {
216 if(LOGGER.isDebugEnabled())
217 LOGGER.debug("result is of type BindingContext; return type: " + (((BindingContext)result).unwrap().getClass()));
218
219 return ((BindingContext)result).unwrap();
220 } else
221 return result;
222 } else {
223 for(int i = 0; i < index; i++) {
224 if(i == 0) {
225 result = vr.resolveVariable(_context.getName());
226 } else
227 result = _tokenArray[i].evaluate(result);
228 }
229
230 return result;
231 }
232 }
233 }
234 |
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