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 * https://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.apache.directory.api.i18n.I18n;
24 import org.slf4j.Logger;
25 import org.slf4j.LoggerFactory;
26
27 import java.lang.reflect.Method;
28 import java.util.Arrays;
29
30
31 /**
32 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
33 */
34 public final class MethodUtils
35 {
36 /** The logger. */
37 private static final Logger LOG = LoggerFactory.getLogger( MethodUtils.class );
38
39
40 /**
41 * Private constructor.
42 */
43 private MethodUtils()
44 {
45 }
46
47
48 /**
49 * A replacement for {@link java.lang.Class#getMethod} with extended capability.
50 *
51 * <p>
52 * This method returns parameter-list assignment-compatible method as well as
53 * exact-signature matching method.
54 *
55 * @param clazz The class which will be queried for the method.
56 * @param candidateMethodName Name of the method been looked for.
57 * @param candidateParameterTypes Types of the parameters in the signature of the method being loooked for.
58 * @return The Method found.
59 * @throws NoSuchMethodException when the method cannot be found
60 */
61 public static Method getAssignmentCompatibleMethod( Class<?> clazz,
62 String candidateMethodName,
63 Class<?>[] candidateParameterTypes
64 ) throws NoSuchMethodException
65 {
66 if ( LOG.isDebugEnabled() )
67 {
68 StringBuilder buf = new StringBuilder();
69 buf.append( "call to getAssignmentCompatibleMethod(): \n\tclazz = " );
70 buf.append( clazz.getName() );
71 buf.append( "\n\tcandidateMethodName = " );
72 buf.append( candidateMethodName );
73 buf.append( "\n\tcandidateParameterTypes = " );
74
75 for ( Class<?> argClass : candidateParameterTypes )
76 {
77 buf.append( "\n\t\t" );
78 buf.append( argClass.getName() );
79 }
80
81 if ( LOG.isDebugEnabled() )
82 {
83 LOG.debug( buf.toString() );
84 }
85 }
86
87 try
88 {
89 // Look for exactly the same signature.
90 Method exactMethod = clazz.getMethod( candidateMethodName, candidateParameterTypes );
91
92 if ( exactMethod != null )
93 {
94 return exactMethod;
95 }
96 }
97 catch ( Exception e )
98 {
99 if ( LOG.isInfoEnabled() )
100 {
101 LOG.info( I18n.msg( I18n.MSG_17009_NO_EXACT_MATCH, candidateMethodName, e ) );
102 }
103 }
104
105 /**
106 * Look for the assignment-compatible signature.
107 */
108
109 // Get all methods of the class.
110 Method[] methods = clazz.getMethods();
111
112 // For each method of the class...
113 for ( int mx = 0; mx < methods.length; mx++ )
114 {
115 // If the method name does not match...
116 if ( !candidateMethodName.equals( methods[mx].getName() ) )
117 {
118 // ... Go on with the next method.
119 continue;
120 }
121
122 // ... Get parameter types list.
123 Class<?>[] parameterTypes = methods[mx].getParameterTypes();
124
125 // If parameter types list length mismatch...
126 if ( parameterTypes.length != candidateParameterTypes.length )
127 {
128 // ... Go on with the next method.
129 continue;
130 }
131 // If parameter types list length is OK...
132 // ... For each parameter of the method...
133 for ( int px = 0; px < parameterTypes.length; px++ )
134 {
135 // ... If the parameter is not assignment-compatible with the candidate parameter type...
136 if ( !parameterTypes[px].isAssignableFrom( candidateParameterTypes[px] ) )
137 {
138 // ... Go on with the next method.
139 break;
140 }
141 }
142
143 // Return the only one possible and found method.
144 return methods[mx];
145 }
146
147 throw new NoSuchMethodException( clazz.getName() + "." + candidateMethodName
148 + "(" + Arrays.toString( candidateParameterTypes ) + ")" );
149 }
150 }