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16 package org.apache.cocoon.components.treeprocessor;
17
18 import java.util.ArrayList  ;
19 import java.util.Collections ;
20 import java.util.HashMap ;
21 import java.util.Iterator ;
22 import java.util.List ;
23 import java.util.Map ;
24
25 import org.apache.avalon.framework.parameters.Parameters;
26 import org.apache.cocoon.sitemap.PatternException;
27
28
35
36 public abstract class MapStackResolver {
37
38 public static final Map EMPTY_MAP = Collections.unmodifiableMap(new java.util.HashMap (0));
39
40
43 public abstract String resolve(List mapStack) throws PatternException;
44
45
48 public static boolean needsResolve(String expression) {
49 if (expression == null || expression.length() == 0) {
50 return false;
51 }
52
53 if (expression.charAt(0) == '{') {
55 return true;
56 }
57
58 if (expression.length() < 2) {
59 return false;
60 }
61
62 int pos = 1;
64 while ( (pos = expression.indexOf('{', pos)) != -1) {
65 if (expression.charAt(pos - 1) != '\\') {
67 return true;
69 }
70 pos++;
71 }
72 return false;
74 }
75
76
83 public static String unescape(String expression) {
84 if (expression == null || expression.indexOf("\\{") == -1) {
86 return expression;
87 }
88
89 StringBuffer buf = new StringBuffer ();
90 for (int i = 0; i < expression.length(); i++) {
91 char ch = expression.charAt(i);
92 if (ch != '\\' || i >= (expression.length() - 1) || expression.charAt(i+1) != '{') {
93 buf.append(ch);
94 }
95 }
96
97 return buf.toString();
98 }
99
100
104 public static MapStackResolver getResolver(String expression) throws PatternException {
105 if (needsResolve(expression)) {
106 return new CompiledResolver(expression);
108 } else {
109 return new NullResolver(expression);
110 }
111 }
112
113
119 public static Parameters buildParameters(Map expressions, List mapStack) throws PatternException {
120 if (expressions == null || expressions.size() == 0) {
121 return Parameters.EMPTY_PARAMETERS;
122 }
123
124 Parameters result = new Parameters();
125
126 Iterator iter = expressions.entrySet().iterator();
127 while (iter.hasNext()) {
128 Map.Entry entry = (Map.Entry )iter.next();
129 result.setParameter(
130 ((MapStackResolver)entry.getKey()).resolve(mapStack),
131 ((MapStackResolver)entry.getValue()).resolve(mapStack)
132 );
133 }
134
135 return result;
136 }
137
138
144 public static Map resolveMap(Map expressions, List mapStack) throws PatternException {
145 int size;
146 if (expressions == null || (size = expressions.size()) == 0) {
147 return EMPTY_MAP;
148 }
149
150 Map result = new HashMap (size);
151
152 Iterator iter = expressions.entrySet().iterator();
153 while (iter.hasNext()) {
154 Map.Entry entry = (Map.Entry )iter.next();
155 result.put(
156 ((MapStackResolver)entry.getKey()).resolve(mapStack),
157 ((MapStackResolver)entry.getValue()).resolve(mapStack)
158 );
159 }
160
161 return result;
162 }
163
164
168 private static class NullResolver extends MapStackResolver {
169 private String originalExpr = null;
170 private String expression = null;
171
172 public NullResolver(String expression) {
173 if (expression != null) {
174 this.originalExpr = expression;
175 this.expression = unescape(expression);
176 }
177 }
178
179 public String toString() {
180 return this.originalExpr;
181 }
182
183 public final String resolve(List mapStack) {
184 return this.expression;
185 }
186 }
187
188
190
193 private static class CompiledResolver extends MapStackResolver {
194 private String originalExpr;
195
196 private String [] strings;
197 private int[] levels;
198
199 public CompiledResolver(String expression) throws PatternException {
200 this.originalExpr = expression;
201 compile(expression);
202 }
203
204 public String toString() {
205 return this.originalExpr;
206 }
207
208 private void compile(String expr) throws PatternException {
209
211 List stringList = new ArrayList ();
212 List levelList = new ArrayList ();
213
214 int length = expr.length();
215 int prev = 0;
217 comp : while(prev < length) {
218 int pos = prev;
220 while(pos < length &&
221 (pos = expr.indexOf('{', pos)) != -1 &&
222 (pos != 0 && expr.charAt(pos - 1) == '\\')) {
223 pos++;
224 }
225
226 if (pos >= length || pos == -1) {
227 if (prev < length) {
229 stringList.add(unescape(expr.substring(prev)));
230 levelList.add(new Integer (-1));
231 }
232 break comp;
233 }
234
235 pos++;
237
238 if (prev < pos-1) {
240 stringList.add(unescape(expr.substring(prev, pos - 1)));
241 levelList.add(new Integer (-1));
242 }
243
244 int level = 1; while(expr.startsWith("../", pos)) {
247 level++;
248 pos += "../".length();
249 }
250
251 int end = expr.indexOf('}', pos);
252 if (end == -1) {
253 throw new PatternException("Unmatched '{' in " + expr);
254 }
255
256 stringList.add(expr.substring(pos, end));
257 levelList.add(new Integer (level));
258
259 prev = end + 1;
260 }
261
262 this.strings = new String [stringList.size()];
263 this.levels = new int[stringList.size()];
264 for (int i = 0; i < strings.length; i++) {
265 this.strings[i] = (String )stringList.get(i);
266 this.levels[i] = ((Integer )levelList.get(i)).intValue();
267 }
268 }
269
270 public final String resolve(List mapStack) throws PatternException {
271 StringBuffer result = new StringBuffer ();
272 int stackSize = mapStack.size();
273
274 for (int i = 0; i < this.strings.length; i++) {
275 int level = this.levels[i];
276 if (level == -1) {
277 result.append(this.strings[i]);
278
279 } else {
280 if (level > stackSize) {
281 throw new PatternException("Error while evaluating '" + this.originalExpr +
282 "' : not so many levels");
283 }
284
285 Object value = ((Map )mapStack.get(stackSize - level)).get(this.strings[i]);
286 if (value != null) {
287 result.append(value);
288 }
289 }
290 }
291
292 return result.toString();
293 }
294
295 }
304
305 }
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