Source code: ognl/Evaluation.java
1 //--------------------------------------------------------------------------
2 // Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
3 // All rights reserved.
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 // Redistributions of source code must retain the above copyright notice,
10 // this list of conditions and the following disclaimer.
11 // Redistributions in binary form must reproduce the above copyright
12 // notice, this list of conditions and the following disclaimer in the
13 // documentation and/or other materials provided with the distribution.
14 // Neither the name of the Drew Davidson nor the names of its contributors
15 // may be used to endorse or promote products derived from this software
16 // without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 // COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
25 // OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 // AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
28 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
29 // DAMAGE.
30 //--------------------------------------------------------------------------
31 package ognl;
32
33 import java.util.*;
34
35 /**
36 An <code>Evaluation</code> is and object that holds a node being evaluated
37 and the source from which that node will take extract its
38 value. It refers to child evaluations that occur as
39 a result of the nodes' evaluation.
40 */
41 public class Evaluation extends Object
42 {
43 private SimpleNode node;
44 private Object source;
45 private boolean setOperation;
46 private Object result;
47 private Throwable exception;
48 private Evaluation parent;
49 private Evaluation next;
50 private Evaluation previous;
51 private Evaluation firstChild;
52 private Evaluation lastChild;
53
54 /**
55 Constructs a new "get" <code>Evaluation</code> from the node and source given.
56 */
57 public Evaluation(SimpleNode node, Object source)
58 {
59 super();
60 this.node = node;
61 this.source = source;
62 }
63
64 /**
65 Constructs a new <code>Evaluation</code> from the node and source given.
66 If <code>setOperation</code> is true this <code>Evaluation</code> represents
67 a "set" as opposed to a "get".
68 */
69 public Evaluation(SimpleNode node, Object source, boolean setOperation)
70 {
71 this(node, source);
72 this.setOperation = setOperation;
73 }
74
75 /**
76 Returns the <code>SimpleNode</code> for this <code>Evaluation</code>
77 */
78 public SimpleNode getNode()
79 {
80 return node;
81 }
82
83 /**
84 Sets the node of the evaluation. Normally applications do not need to
85 set this. Notable exceptions to this rule are custom evaluators that
86 choose between navigable objects (as in a multi-root evaluator where
87 the navigable node is chosen at runtime).
88 */
89 public void setNode(SimpleNode value)
90 {
91 node = value;
92 }
93
94 /**
95 Returns the source object on which this Evaluation operated.
96 */
97 public Object getSource()
98 {
99 return source;
100 }
101
102 /**
103 Sets the source of the evaluation. Normally applications do not need to
104 set this. Notable exceptions to this rule are custom evaluators that
105 choose between navigable objects (as in a multi-root evaluator where
106 the navigable node is chosen at runtime).
107 */
108 public void setSource(Object value)
109 {
110 source = value;
111 }
112
113 /**
114 Returns true if this Evaluation represents a set operation.
115 */
116 public boolean isSetOperation()
117 {
118 return setOperation;
119 }
120
121 /**
122 Marks the Evaluation as a set operation if the value is true, else
123 marks it as a get operation.
124 */
125 public void setSetOperation(boolean value)
126 {
127 setOperation = value;
128 }
129
130 /**
131 Returns the result of the Evaluation, or null if it was a set operation.
132 */
133 public Object getResult()
134 {
135 return result;
136 }
137
138 /**
139 Sets the result of the Evaluation. This method is normally only used
140 interally and should not be set without knowledge of what you are doing.
141 */
142 public void setResult(Object value)
143 {
144 result = value;
145 }
146
147 /**
148 Returns the exception that occurred as a result of evaluating the
149 Evaluation, or null if no exception occurred.
150 */
151 public Throwable getException()
152 {
153 return exception;
154 }
155
156 /**
157 Sets the exception that occurred as a result of evaluating the
158 Evaluation. This method is normally only used interally and
159 should not be set without knowledge of what you are doing.
160 */
161 public void setException(Throwable value)
162 {
163 exception = value;
164 }
165
166 /**
167 Returns the parent evaluation of this evaluation. If this returns
168 null then it is is the root evaluation of a tree.
169 */
170 public Evaluation getParent()
171 {
172 return parent;
173 }
174
175 /**
176 Returns the next sibling of this evaluation. Returns null if
177 this is the last in a chain of evaluations.
178 */
179 public Evaluation getNext()
180 {
181 return next;
182 }
183
184 /**
185 Returns the previous sibling of this evaluation. Returns null if
186 this is the first in a chain of evaluations.
187 */
188 public Evaluation getPrevious()
189 {
190 return previous;
191 }
192
193 /**
194 Returns the first child of this evaluation. Returns null if
195 there are no children.
196 */
197 public Evaluation getFirstChild()
198 {
199 return firstChild;
200 }
201
202 /**
203 Returns the last child of this evaluation. Returns null if
204 there are no children.
205 */
206 public Evaluation getLastChild()
207 {
208 return lastChild;
209 }
210
211 /**
212 Gets the first descendent. In any Evaluation tree this will the
213 Evaluation that was first executed.
214 */
215 public Evaluation getFirstDescendant()
216 {
217 if (firstChild != null) {
218 return firstChild.getFirstDescendant();
219 }
220 return this;
221 }
222
223 /**
224 Gets the last descendent. In any Evaluation tree this will the
225 Evaluation that was most recently executing.
226 */
227 public Evaluation getLastDescendant()
228 {
229 if (lastChild != null) {
230 return lastChild.getLastDescendant();
231 }
232 return this;
233 }
234
235 /**
236 Adds a child to the list of children of this evaluation. The
237 parent of the child is set to the receiver and the children
238 references are modified in the receiver to reflect the new child.
239 The lastChild of the receiver is set to the child, and the
240 firstChild is set also if child is the first (or only) child.
241 */
242 public void addChild(Evaluation child)
243 {
244 if (firstChild == null) {
245 firstChild = lastChild = child;
246 } else {
247 if (firstChild == lastChild) {
248 firstChild.next = child;
249 lastChild = child;
250 lastChild.previous = firstChild;
251 } else {
252 child.previous = lastChild;
253 lastChild.next = child;
254 lastChild = child;
255 }
256 }
257 child.parent = this;
258 }
259
260 /**
261 Reinitializes this Evaluation to the parameters specified.
262 */
263 public void init(SimpleNode node, Object source, boolean setOperation)
264 {
265 this.node = node;
266 this.source = source;
267 this.setOperation = setOperation;
268 result = null;
269 exception = null;
270 parent = null;
271 next = null;
272 previous = null;
273 firstChild = null;
274 lastChild = null;
275 }
276
277 /**
278 Resets this Evaluation to the initial state.
279 */
280 public void reset()
281 {
282 init(null, null, false);
283 }
284
285 /**
286 Produces a String value for the Evaluation. If compact is
287 true then a more compact form of the description only including
288 the node type and unique identifier is shown, else a full
289 description including source and result are shown. If showChildren
290 is true the child evaluations are printed using the depth string
291 given as a prefix.
292 */
293 public String toString(boolean compact, boolean showChildren, String depth)
294 {
295 String stringResult;
296
297 if (compact) {
298 stringResult = depth + "<" + node.getClass().getName() + " " + System.identityHashCode(this) + ">";
299 } else {
300 String ss = (source != null) ? source.getClass().getName() : "null",
301 rs = (result != null) ? result.getClass().getName() : "null";
302
303 stringResult = depth + "<" + node.getClass().getName() + ": [" + (setOperation ? "set" : "get") + "] source = " + ss + ", result = " + result + " [" + rs + "]>";
304 }
305 if (showChildren) {
306 Evaluation child = firstChild;
307
308 stringResult += "\n";
309 while (child != null) {
310 stringResult += child.toString(compact, depth + " ");
311 child = child.next;
312 }
313 }
314 return stringResult;
315 }
316
317 /**
318 Produces a String value for the Evaluation. If compact is
319 true then a more compact form of the description only including
320 the node type and unique identifier is shown, else a full
321 description including source and result are shown. Child
322 evaluations are printed using the depth string given as a prefix.
323 */
324 public String toString(boolean compact, String depth)
325 {
326 return toString(compact, true, depth);
327 }
328
329 /**
330 Returns a String description of the Evaluation.
331 */
332 public String toString()
333 {
334 return toString(false, "");
335 }
336 }