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1
8 package org.codehaus.loom.components.util.infobuilder;
9
10 import java.lang.reflect.Method  ;
11 import java.util.ArrayList ;
12 import java.util.List ;
13
14 import org.codehaus.loom.components.util.info.ComponentInfo;
15 import org.codehaus.loom.components.util.info.DependencyDescriptor;
16 import org.codehaus.loom.components.util.info.SchemaDescriptor;
17 import org.codehaus.loom.components.util.info.ServiceDescriptor;
18 import org.codehaus.metaclass.Attributes;
19 import org.codehaus.metaclass.model.Attribute;
20
21
28 public final class MetaClassBlockInfoReader implements BlockInfoReader
29 {
30 public ComponentInfo buildComponentInfo( final Class type )
31 throws Exception
32 {
33 final Attribute attribute =
34 Attributes.getAttribute( type, "dna.component" );
35 if( null == attribute )
36 {
37 final String message =
38 "Type " +
39 type.getName() +
40 " does not specify the " +
41 "required MetaClass attributes to be a Component";
42 throw new Exception ( message );
43 }
44 final ServiceDescriptor[] services = buildServices( type );
45
46 final DependencyDescriptor[] dependencies =
47 buildDependencies( type );
48
49 final SchemaDescriptor schema = buildConfigurationSchema( type );
50
51 return new ComponentInfo( type,
52 services,
53 dependencies,
54 schema );
55 }
56
57
64 private SchemaDescriptor buildConfigurationSchema( final Class type )
65 {
66 final Class [] types =
67 new Class []{org.apache.avalon.framework.configuration.Configuration.class};
68 try
69 {
70 final Method method = type.getMethod( "configure", types );
71 final Attribute attribute =
72 Attributes.getAttribute( method, "dna.configuration" );
73 if( null == attribute )
74 {
75 return null;
76 }
77 final String location = attribute.getParameter( "location" );
78 final String schemaType = attribute.getParameter( "type" );
79 return new SchemaDescriptor( location, schemaType );
80 }
81 catch( NoSuchMethodException e )
82 {
83 return null;
84 }
85 }
86
87
96 private DependencyDescriptor[] buildDependencies( final Class type )
97 {
98 final Method method = getDependencyMethod( type );
99 if( null == method )
100 {
101 return DependencyDescriptor.EMPTY_SET;
102 }
103 final List deps = new ArrayList ();
104
105 final Attribute[] attributes =
106 Attributes.getAttributes( method, "dna.dependency" );
107 for( int i = 0; i < attributes.length; i++ )
108 {
109 final Attribute attribute = attributes[i];
110 final String key = attribute.getParameter( "key" );
111 final String depType = attribute.getParameter( "type" );
112 final boolean optional =
113 attribute.getParameter( "optional", "" ).equals( "true" );
114 deps.add( new DependencyDescriptor( key, depType, optional ) );
115 }
116
117 return (DependencyDescriptor[])deps.toArray( DependencyDescriptor.EMPTY_SET );
118 }
119
120
127 private Method getDependencyMethod( final Class type )
128 {
129 try
130 {
131 final Class [] types1 =
132 new Class []{org.apache.avalon.framework.component.ComponentManager.class};
133 return type.getMethod( "compose", types1 );
134 }
135 catch( final NoSuchMethodException nsme )
136 {
137 }
138 try
139 {
140 final Class [] types2 =
141 new Class []{org.apache.avalon.framework.service.ServiceManager.class};
142 return type.getMethod( "service", types2 );
143 }
144 catch( NoSuchMethodException e )
145 {
146 }
147 return null;
148 }
149
150
159 private ServiceDescriptor[] buildServices( final Class type )
160 {
161 final List services = new ArrayList ();
162
163 final Attribute[] attributes =
164 Attributes.getAttributes( type, "dna.service" );
165 for( int i = 0; i < attributes.length; i++ )
166 {
167 final Attribute attribute = attributes[i];
168 final String serviceType = attribute.getParameter( "type" );
169 services.add( new ServiceDescriptor( serviceType ) );
170 }
171
172 return (ServiceDescriptor[])services.toArray( ServiceDescriptor.EMPTY_SET );
173 }
174 }
175 |
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