FilteredPropertiesInjector


1   package jfun.yan;
2   
3   import java.beans.IntrospectionException  ;
4   import java.lang.reflect.Method  ;
5   import java.util.HashSet  ;
6   import java.util.Iterator  ;
7   import java.util.Set  ;
8   
9   import jfun.util.beans.BeanType;
10  import jfun.yan.util.MemberPredicate;
11  import jfun.yan.util.Utils;
12  
13  /**
14   * This implementation only attempts to inject a property when this property
15   * satisfies a MemberPredicate object.
16   * <p>
17   * @author Ben Yu
18   * Dec 31, 2005 12:51:53 PM
19   */
20  public class FilteredPropertiesInjector implements PropertiesInjector {
21    /*The meta information of the bean. null if unknown*/
22    private final BeanType btype;
23    private final MemberPredicate filter;
24    private final Set   propnames;
25    
26    /**
27     * Create an instance of FilteredPropertiesInjector. 
28     * If type is null, dynamic binding will be used.
29     * @param type the bean class.
30     * @param pred the MemberPredicate object.
31     * @return the instance.
32     * @throws IntrospectionException
33     */
34    public static PropertiesInjector instance(Class   type, 
35        MemberPredicate pred)
36    throws IntrospectionException  {
37      final BeanType bt = Utils.toBeanType(type);
38      return new FilteredPropertiesInjector(bt, pred);
39    }
40    /**
41     * Create an instance of FilteredPropertiesInjector.
42     * @param btype the bean type. If null, dynamic binding is used.
43     * @param pred the MemberPredicate object to filter the properties.
44     */
45    public FilteredPropertiesInjector(final BeanType btype,
46        final MemberPredicate pred){
47      this.btype = btype;
48      this.filter = pred;
49      this.propnames = btype==null?null:getPropertyNames(btype, pred);
50    }
51    private BeanType obtainBeanType(Class   type){
52      //dynamically get the bean type.
53      //if the bean type is not early bound, 
54      //use the object type to dynamically create it.
55      if(btype!=null) return btype;
56      else{
57        return jfun.yan.util.Utils.toBeanType(type);
58      }
59    }
60    public void injectProperties(Object   obj, Dependency dep){
61      if(obj==null){
62        throw new NullBeanObjectException("null component");
63      }
64      //dynamically resolve bean type and properties if necessary.
65      final Class   objtype = obj.getClass();
66      final BeanType btype = obtainBeanType(objtype);
67      final Set   props = getPropertyNames(btype);
68      Utils.injectProperties(btype, obj, props, dep);
69     }
70    public void verifyProperties(Class   type, Dependency dep){
71      //dynamically resolve bean type and properties if necessary.
72      //the type cannot be null now.
73      final BeanType btype = obtainBeanType(type);
74      final Set   props = getPropertyNames(btype);
75      Utils.verifyProperties(btype, props, dep);
76    }
77    public String   toString(){
78      return "bean";
79    }
80    private Set   getPropertyNames(BeanType bt){
81      return propnames==null?getPropertyNames(bt, this.filter):propnames;
82    }
83    private static Set   getPropertyNames(BeanType bt, MemberPredicate pred){
84      final HashSet   props = new HashSet  ();
85      for(Iterator   it = bt.getPropertyNames().iterator(); it.hasNext();){
86        final String   name = (String  )it.next();
87        Method   mtd = bt.getWriter(name);
88        if(mtd==null)
89          mtd = bt.getIndexedWriter(name);
90        if(mtd!=null){
91          if(pred.isMember(name, mtd)){
92            props.add(name);
93          }
94        }
95      }
96      return props;
97    }
98  }
99
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags