1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.api.util;
21
22
23 import org.slf4j.Logger;
24 import org.slf4j.LoggerFactory;
25
26 import java.lang.reflect.Method;
27 import java.util.Arrays;
28
29
30 /**
31 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
32 */
33 public final class MethodUtils
34 {
35 /** The logger. */
36 private static final Logger LOG = LoggerFactory.getLogger( MethodUtils.class );
37
38
39 /**
40 * Private constructor.
41 */
42 private MethodUtils()
43 {
44 }
45
46
47 /**
48 * A replacement for {@link java.lang.Class#getMethod} with extended capability.
49 *
50 * <p>
51 * This method returns parameter-list assignment-compatible method as well as
52 * exact-signature matching method.
53 *
54 * @param clazz The class which will be queried for the method.
55 * @param candidateMethodName Name of the method been looked for.
56 * @param candidateParameterTypes Types of the parameters in the signature of the method being loooked for.
57 * @return The Method found.
58 * @throws NoSuchMethodException when the method cannot be found
59 */
60 public static Method getAssignmentCompatibleMethod( Class<?> clazz,
61 String candidateMethodName,
62 Class<?>[] candidateParameterTypes
63 ) throws NoSuchMethodException
64 {
65 if ( LOG.isDebugEnabled() )
66 {
67 StringBuilder buf = new StringBuilder();
68 buf.append( "call to getAssignmentCompatibleMethod(): \n\tclazz = " );
69 buf.append( clazz.getName() );
70 buf.append( "\n\tcandidateMethodName = " );
71 buf.append( candidateMethodName );
72 buf.append( "\n\tcandidateParameterTypes = " );
73
74 for ( Class<?> argClass : candidateParameterTypes )
75 {
76 buf.append( "\n\t\t" );
77 buf.append( argClass.getName() );
78 }
79
80 LOG.debug( buf.toString() );
81 }
82
83 try
84 {
85 // Look for exactly the same signature.
86 Method exactMethod = clazz.getMethod( candidateMethodName, candidateParameterTypes );
87
88 if ( exactMethod != null )
89 {
90 return exactMethod;
91 }
92 }
93 catch ( Exception e )
94 {
95 LOG.info( "Could not find accessible exact match for candidateMethod {}", candidateMethodName, e );
96 }
97
98 /**
99 * Look for the assignment-compatible signature.
100 */
101
102 // Get all methods of the class.
103 Method[] methods = clazz.getMethods();
104
105 // For each method of the class...
106 for ( int mx = 0; mx < methods.length; mx++ )
107 {
108 // If the method name does not match...
109 if ( !candidateMethodName.equals( methods[mx].getName() ) )
110 {
111 // ... Go on with the next method.
112 continue;
113 }
114
115 // ... Get parameter types list.
116 Class<?>[] parameterTypes = methods[mx].getParameterTypes();
117
118 // If parameter types list length mismatch...
119 if ( parameterTypes.length != candidateParameterTypes.length )
120 {
121 // ... Go on with the next method.
122 continue;
123 }
124 // If parameter types list length is OK...
125 // ... For each parameter of the method...
126 for ( int px = 0; px < parameterTypes.length; px++ )
127 {
128 // ... If the parameter is not assignment-compatible with the candidate parameter type...
129 if ( !parameterTypes[px].isAssignableFrom( candidateParameterTypes[px] ) )
130 {
131 // ... Go on with the next method.
132 break;
133 }
134 }
135
136 // Return the only one possible and found method.
137 return methods[mx];
138 }
139
140 throw new NoSuchMethodException( clazz.getName() + "." + candidateMethodName
141 + "(" + Arrays.toString( candidateParameterTypes ) + ")" );
142 }
143 }