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1 package org.jbpm.instantiation;
2
3 import java.lang.reflect.*;
4 import java.util.*;
5
6 import org.apache.commons.logging.*;
7 import org.dom4j.*;
8
9 public class FieldInstantiator implements Instantiator {
10
11 public Object  instantiate(Class clazz, String configuration) {
12
13 Object newInstance = newInstance(clazz);
15
16 Element configurationElement = parseConfiguration(configuration);
18
19 Iterator iter = configurationElement.elements().iterator();
21 while( iter.hasNext() ) {
22 Element propertyElement = (Element) iter.next();
23 String propertyName = propertyElement.getName();
24 setPropertyValue(clazz, newInstance, propertyName, propertyElement);
25 }
26 return newInstance;
27 }
28
29 protected void setPropertyValue(Class clazz, Object newInstance, String propertyName, Element propertyElement) {
30 try {
31 Field f = clazz.getDeclaredField(propertyName);
32 f.setAccessible(true);
33 f.set(newInstance, getValue(f.getType(), propertyElement));
34 } catch (Exception e) {
35 log.error( "couldn't parse set field '"+propertyName+"' to value '"+propertyElement.asXML()+"'", e );
36 }
37 }
38
39 protected Element parseConfiguration(String configuration) {
40 Element element = null;
41 try {
42 element = DocumentHelper.parseText( "<action>"+configuration+"</action>" ).getRootElement();
43 } catch (DocumentException e) {
44 log.error( "couldn't parse bean configuration : " + configuration, e );
45 throw new RuntimeException (e);
46 }
47 return element;
48 }
49
50 protected Object newInstance(Class clazz) {
51 Object newInstance = null;
52 try {
53 newInstance = clazz.newInstance();
54 } catch (Exception e) {
55 log.error( "couldn't instantiate type '" + clazz.getName() + "' with the default constructor" );
56 throw new RuntimeException (e);
57 }
58 return newInstance;
59 }
60
61 public static Object getValue(Class type, Element propertyElement) {
62 Object value = null;
64 try {
65
66 if ( type == String .class ) {
67 value = propertyElement.getTextTrim();
68 } else if ( (type==Integer .class) || (type==int.class) ) {
69 value = new Integer ( propertyElement.getTextTrim() );
70 } else if ( (type==Long .class) || (type==long.class) ) {
71 value = new Long ( propertyElement.getTextTrim() );
72 } else if ( (type==Float .class ) || (type==float.class) ) {
73 value = new Float ( propertyElement.getTextTrim() );
74 } else if ( (type==Double .class ) || (type==double.class) ) {
75 value = new Double ( propertyElement.getTextTrim() );
76 } else if ( (type==Boolean .class ) || (type==boolean.class) ) {
77 value = Boolean.valueOf( propertyElement.getTextTrim() );
78 } else if ( (type==Character .class ) || (type==char.class) ) {
79 value = new Character ( propertyElement.getTextTrim().charAt(0) );
80 } else if ( (type==Short .class ) || (type==short.class) ) {
81 value = new Short ( propertyElement.getTextTrim() );
82 } else if ( (type==Byte .class ) || (type==byte.class) ) {
83 value = new Byte ( propertyElement.getTextTrim() );
84 } else if (type.isAssignableFrom(List.class)) {
85 value = getCollection(propertyElement, new ArrayList());
86 } else if (type.isAssignableFrom(Set.class)) {
87 value = getCollection(propertyElement, new HashSet());
88 } else if (type.isAssignableFrom(Collection.class)) {
89 value = getCollection(propertyElement, new ArrayList());
90 } else if (type.isAssignableFrom(Map.class)) {
91 value = getMap(propertyElement, new HashMap());
92 } else if ( type==Element.class ) {
93 value = propertyElement;
94 } else {
95 Constructor constructor = type.getConstructor(new Class []{String .class});
96 if ( (propertyElement.isTextOnly())
97 && (constructor!=null) ) {
98 value = constructor.newInstance(new Object []{propertyElement.getTextTrim()});
99 }
100 }
101 } catch (Exception e) {
102 log.error("couldn't parse the bean property value '" + propertyElement.asXML() + "' to a '" + type.getName() + "'" );
103 throw new RuntimeException ( e );
104 }
105 return value;
106 }
107
108 private static Object getMap(Element mapElement, Map map) {
109 Class keyClass = String .class;
110 String keyType = mapElement.attributeValue("key-type");
111 if (keyType!=null) {
112 keyClass = ClassLoaderUtil.loadClass(keyType);
113 }
114
115 Class valueClass = String .class;
116 String valueType = mapElement.attributeValue("value-type");
117 if (keyType!=null) {
118 valueClass = ClassLoaderUtil.loadClass(valueType);
119 }
120
121 Iterator iter = mapElement.elementIterator();
122 while (iter.hasNext()) {
123 Element element = (Element) iter.next();
124 Element keyElement = element.element("key");
125 Element valueElement = element.element("value");
126
127 map.put(getValue(keyClass, keyElement), getValue(valueClass, valueElement));
128 }
129 return map;
130 }
131
132 private static Object getCollection(Element collectionElement, Collection collection) {
133 Class elementClass = String .class;
134 String elementType = collectionElement.attributeValue("element-type");
135 if (elementType!=null) {
136 elementClass = ClassLoaderUtil.loadClass(elementType);
137 }
138 Iterator iter = collectionElement.elementIterator();
139 while (iter.hasNext()) {
140 Element element = (Element) iter.next();
141 collection.add(getValue(elementClass, element));
142 }
143 return collection;
144 }
145
146 private static final Log log = LogFactory.getLog(FieldInstantiator.class);
147 }
148 |
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