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1
30
31
34 package com.nightlabs.inheritance;
35
36 import java.lang.reflect.Field  ;
37 import java.lang.reflect.Modifier ;
38 import java.util.ArrayList ;
39 import java.util.Iterator ;
40
41 import org.apache.log4j.Logger;
42
43
46 public class InheritenceManager
47 {
48 public static final Logger LOGGER = Logger.getLogger(InheritenceManager.class);
49
50 public InheritenceManager() { }
51
52 protected void callPreInherit(Inheritable obj)
53 {
54 if (!(obj instanceof InheritanceCallbacks))
55 return;
56
57 ((InheritanceCallbacks)obj).preInherit();
58 }
59
60 protected void callPostInherit(Inheritable obj)
61 {
62 if (!(obj instanceof InheritanceCallbacks))
63 return;
64
65 ((InheritanceCallbacks)obj).postInherit();
66 }
67
68 public void inheritAllFields(Inheritable mother, Inheritable child)
69 {
70 callPreInherit(mother);
71 callPreInherit(child);
72
73 Class clazz = mother.getClass();
74 ArrayList allFields = new ArrayList ();
75
76 Class fcl = clazz;
77 while (fcl != Object .class) {
78 Field [] fields = fcl.getDeclaredFields();
79 for (int i = 0; i < fields.length; ++i)
80 allFields.add(fields[i]);
81
82 fcl = fcl.getSuperclass();
83 }
85 for (Iterator it = allFields.iterator(); it.hasNext(); ) {
86 Field f = (Field )it.next();
87
88 if (Modifier.isStatic(f.getModifiers()))
89 continue;
90
91 FieldMetaData fmd = mother.getFieldMetaData(f.getName());
92 if (fmd != null)
93 inheritField(mother, child, clazz, f, fmd);
94 }
96 callPostInherit(mother);
97 callPostInherit(child);
98 }
99
100
103 protected void inheritField(
104 Inheritable mother, Inheritable child,
105 Class motherClass, Field field,
106 FieldMetaData motherFieldMetaData)
107 {
108 LOGGER.debug("inheritField(...): mother=\""+mother+"\" child=\""+child+"\" field=\""+field.getName()+"\"");
109
110 Class childClass = child.getClass();
111 if (!motherClass.isAssignableFrom(childClass))
112 throw new IllegalArgumentException ("Child class is not identical to or inheriting the mother class!");
113
114 FieldMetaData childFieldMetaData = child.getFieldMetaData(field.getName());
115 if (childFieldMetaData == null)
116 throw new NullPointerException ("Child \""+child+"\" returned no FieldMetaData for field \""+field.getName()+"\"!");
117
118
119 if ((motherFieldMetaData.getWritableByChildren() & FieldMetaData.WRITABLEBYCHILDREN_YES) > 0) {
120
121 if ((childFieldMetaData.getWritableByChildren() & FieldMetaData.WRITABLEBYCHILDREN_YES) == 0 &&
122 (childFieldMetaData.getWritableByChildren() & FieldMetaData.WRITABLEBYCHILDREN_INHERITED) > 0)
123 {
124 childFieldMetaData.setWritableByChildren(
125 (byte)(FieldMetaData.WRITABLEBYCHILDREN_YES | FieldMetaData.WRITABLEBYCHILDREN_INHERITED));
126 }
127
128 childFieldMetaData.setWritable(true);
129 }
130 else {
131 if (childFieldMetaData.isWritable())
132 childFieldMetaData.setWritable(false);
133
134 if (childFieldMetaData.getWritableByChildren() == FieldMetaData.WRITABLEBYCHILDREN_YES)
135 childFieldMetaData.setWritableByChildren((byte)(FieldMetaData.WRITABLEBYCHILDREN_NO | FieldMetaData.WRITABLEBYCHILDREN_INHERITED));
136
137 if (!childFieldMetaData.isValueInherited())
138 childFieldMetaData.setValueInherited(true); }
140
141 if (childFieldMetaData.isValueInherited()) {
142 FieldInheriter fieldInheriter = child.getFieldInheriter(field.getName());
143 if (fieldInheriter == null)
144 throw new NullPointerException ("fieldInheriter must not be null!");
145 fieldInheriter.copyFieldValue(
146 mother, child, motherClass, childClass, field, motherFieldMetaData, childFieldMetaData
147 );
148 }
149 }
150 }
151 |
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