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1 package com.tirsen.nanning.samples.prevayler;
2
3 import java.lang.reflect.Array  ;
4 import java.lang.reflect.Field ;
5 import java.lang.reflect.Modifier ;
6 import java.util.HashSet ;
7 import java.util.Set ;
8
9 import org.apache.commons.logging.Log;
10 import org.apache.commons.logging.LogFactory;
11
12 public class ObjectGraphVisitor {
13 private static final Log logger = LogFactory.getLog(ObjectGraphVisitor.class);
14 protected Set visited = new HashSet ();
15
16 public Set getVisited() {
17 return visited;
18 }
19
20 public static void visit(Object o, ObjectGraphVisitor visitor) {
21 visitor.visited.add(o);
22 visitor.visit(o);
23 }
24
25 protected void visit(Object o) {
26 visitInClass(o.getClass(), o);
27 }
28
29 private void visitInClass(Class aClass, Object o) {
30 if (aClass != null && aClass != Object .class) {
31 visitInClass(aClass.getSuperclass(), o);
32 Field [] fields = aClass.getDeclaredFields();
33 for (int fieldIndex = 0; fieldIndex < fields.length; fieldIndex++) {
34 visitField(fields[fieldIndex], o);
35 }
36 }
37 }
38
39 protected void visitField(Field field, Object container) {
40 if (!Modifier.isStatic(field.getModifiers())) {
41 field.setAccessible(true);
42 try {
43 Object nested = field.get(container);
44 if (nested != null && nested.getClass().isArray()) {
45 for (int arrayIndex = 0; arrayIndex < Array.getLength(nested); arrayIndex++) {
46 Object arrayNested = Array.get(nested, arrayIndex);
47 visitNested(arrayNested);
48 }
49 } else {
50 visitNested(nested);
51 }
52
53 } catch (IllegalAccessException e) {
54 logger.warn("could not enter field " + field + " on object " + container, e);
55 }
56 }
57 }
58
59 private void visitNested(Object nested) {
60 if (nested != null && !visited.contains(nested)) {
61 visited.add(nested);
62 visit(nested);
63 }
64 }
65
66 }
67 |
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Java API By Example, From Geeks To Geeks.