View Javadoc
1   /**
2    * Logback: the reliable, generic, fast and flexible logging framework.
3    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4    *
5    * This program and the accompanying materials are dual-licensed under
6    * either the terms of the Eclipse Public License v1.0 as published by
7    * the Eclipse Foundation
8    *
9    *   or (per the licensee's choosing)
10   *
11   * under the terms of the GNU Lesser General Public License version 2.1
12   * as published by the Free Software Foundation.
13   */
14  package ch.qos.logback.core.joran.action;
15  
16  import java.util.Stack;
17  
18  import ch.qos.logback.core.joran.spi.ElementPath;
19  
20  import org.xml.sax.Attributes;
21  
22  import ch.qos.logback.core.joran.spi.InterpretationContext;
23  import ch.qos.logback.core.joran.spi.NoAutoStartUtil;
24  import ch.qos.logback.core.joran.util.PropertySetter;
25  import ch.qos.logback.core.joran.util.beans.BeanDescriptionCache;
26  import ch.qos.logback.core.spi.ContextAware;
27  import ch.qos.logback.core.spi.LifeCycle;
28  import ch.qos.logback.core.util.AggregationType;
29  import ch.qos.logback.core.util.Loader;
30  import ch.qos.logback.core.util.OptionHelper;
31  
32  /**
33   * This action is responsible for tying together a parent object with a child
34   * element for which there is no explicit rule.
35   *
36   * @author Ceki Gülcü
37   */
38  public class NestedComplexPropertyIA extends ImplicitAction {
39  
40      // actionDataStack contains ActionData instances
41      // We use a stack of ActionData objects in order to support nested
42      // elements which are handled by the same NestedComplexPropertyIA instance.
43      // We push a ActionData instance in the isApplicable method (if the
44      // action is applicable) and pop it in the end() method.
45      // The XML well-formedness property will guarantee that a push will eventually
46      // be followed by a corresponding pop.
47      Stack<IADataForComplexProperty> actionDataStack = new Stack<IADataForComplexProperty>();
48  
49      private final BeanDescriptionCache beanDescriptionCache;
50  
51      public NestedComplexPropertyIA(BeanDescriptionCache beanDescriptionCache) {
52          this.beanDescriptionCache = beanDescriptionCache;
53      }
54  
55      public boolean isApplicable(ElementPath elementPath, Attributes attributes, InterpretationContext ic) {
56  
57          String nestedElementTagName = elementPath.peekLast();
58  
59          // calling ic.peekObject with an empty stack will throw an exception
60          if (ic.isEmpty()) {
61              return false;
62          }
63  
64          Object o = ic.peekObject();
65          PropertySetter parentBean = new PropertySetter(beanDescriptionCache, o);
66          parentBean.setContext(context);
67  
68          AggregationType aggregationType = parentBean.computeAggregationType(nestedElementTagName);
69  
70          switch (aggregationType) {
71          case NOT_FOUND:
72          case AS_BASIC_PROPERTY:
73          case AS_BASIC_PROPERTY_COLLECTION:
74              return false;
75  
76              // we only push action data if NestComponentIA is applicable
77          case AS_COMPLEX_PROPERTY_COLLECTION:
78          case AS_COMPLEX_PROPERTY:
79              IADataForComplexProperty ad = new IADataForComplexProperty(parentBean, aggregationType, nestedElementTagName);
80              actionDataStack.push(ad);
81  
82              return true;
83          default:
84              addError("PropertySetter.computeAggregationType returned " + aggregationType);
85              return false;
86          }
87      }
88  
89      public void begin(InterpretationContext ec, String localName, Attributes attributes) {
90          // LogLog.debug("in NestComponentIA begin method");
91          // get the action data object pushed in isApplicable() method call
92          IADataForComplexProperty actionData = (IADataForComplexProperty) actionDataStack.peek();
93  
94          String className = attributes.getValue(CLASS_ATTRIBUTE);
95          // perform variable name substitution
96          className = ec.subst(className);
97  
98          Class<?> componentClass = null;
99          try {
100 
101             if (!OptionHelper.isEmpty(className)) {
102                 componentClass = Loader.loadClass(className, context);
103             } else {
104                 // guess class name via implicit rules
105                 PropertySetter parentBean = actionData.parentBean;
106                 componentClass = parentBean.getClassNameViaImplicitRules(actionData.getComplexPropertyName(), actionData.getAggregationType(),
107                                 ec.getDefaultNestedComponentRegistry());
108             }
109 
110             if (componentClass == null) {
111                 actionData.inError = true;
112                 String errMsg = "Could not find an appropriate class for property [" + localName + "]";
113                 addError(errMsg);
114                 return;
115             }
116 
117             if (OptionHelper.isEmpty(className)) {
118                 addInfo("Assuming default type [" + componentClass.getName() + "] for [" + localName + "] property");
119             }
120 
121             actionData.setNestedComplexProperty(componentClass.getConstructor().newInstance());
122 
123             // pass along the repository
124             if (actionData.getNestedComplexProperty() instanceof ContextAware) {
125                 ((ContextAware) actionData.getNestedComplexProperty()).setContext(this.context);
126             }
127             // addInfo("Pushing component [" + localName
128             // + "] on top of the object stack.");
129             ec.pushObject(actionData.getNestedComplexProperty());
130 
131         } catch (Exception oops) {
132             actionData.inError = true;
133             String msg = "Could not create component [" + localName + "] of type [" + className + "]";
134             addError(msg, oops);
135         }
136 
137     }
138 
139     public void end(InterpretationContext ec, String tagName) {
140 
141         // pop the action data object pushed in isApplicable() method call
142         // we assume that each this begin
143         IADataForComplexProperty actionData = (IADataForComplexProperty) actionDataStack.pop();
144 
145         if (actionData.inError) {
146             return;
147         }
148 
149         PropertySetter nestedBean = new PropertySetter(beanDescriptionCache, actionData.getNestedComplexProperty());
150         nestedBean.setContext(context);
151 
152         // have the nested element point to its parent if possible
153         if (nestedBean.computeAggregationType("parent") == AggregationType.AS_COMPLEX_PROPERTY) {
154             nestedBean.setComplexProperty("parent", actionData.parentBean.getObj());
155         }
156 
157         // start the nested complex property if it implements LifeCycle and is not
158         // marked with a @NoAutoStart annotation
159         Object nestedComplexProperty = actionData.getNestedComplexProperty();
160         if (nestedComplexProperty instanceof LifeCycle && NoAutoStartUtil.notMarkedWithNoAutoStart(nestedComplexProperty)) {
161             ((LifeCycle) nestedComplexProperty).start();
162         }
163 
164         Object o = ec.peekObject();
165 
166         if (o != actionData.getNestedComplexProperty()) {
167             addError("The object on the top the of the stack is not the component pushed earlier.");
168         } else {
169             ec.popObject();
170             // Now let us attach the component
171             switch (actionData.aggregationType) {
172             case AS_COMPLEX_PROPERTY:
173                 actionData.parentBean.setComplexProperty(tagName, actionData.getNestedComplexProperty());
174 
175                 break;
176             case AS_COMPLEX_PROPERTY_COLLECTION:
177                 actionData.parentBean.addComplexProperty(tagName, actionData.getNestedComplexProperty());
178                 break;
179             default:
180                 addError("Unexpected aggregationType " + actionData.aggregationType);
181             }
182         }
183     }
184 
185 }