1 package org.apache.maven.plugin.coreit;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.apache.maven.plugin.AbstractMojo;
23 import org.apache.maven.plugin.MojoExecutionException;
24
25 import java.io.File;
26 import java.io.IOException;
27 import java.lang.reflect.Method;
28 import java.lang.reflect.Modifier;
29 import java.net.URL;
30 import java.net.URLClassLoader;
31 import java.util.ArrayList;
32 import java.util.Collections;
33 import java.util.List;
34 import java.util.Properties;
35
36 /**
37 * Loads classes and/or resources from a class loader and records the results in a properties file.
38 *
39 * @author Benjamin Bentmann
40 *
41 */
42 public abstract class AbstractLoadMojo
43 extends AbstractMojo
44 {
45
46 /**
47 * The comma separated set of classes to load. For each specified qualified class name <code>QCN</code> that was
48 * successfully loaded, the generated properties files will contain a key named <code>QCN</code>. The value of this
49 * key will be the hash code of the requested class. In addition, a key named <code>QCN.methods</code> holds the
50 * comma separated list of all public methods declared directly in that class, in alphabetic order and possibly with
51 * duplicates to account for overloaded methods.
52 *
53 * @parameter property="clsldr.classNames"
54 */
55 protected String classNames;
56
57 /**
58 * The comma separated set of resources to load. For each specified absolute resource path <code>ARP</code> that was
59 * successfully loaded, the generated properties files will contain a key named <code>ARP</code> whose value gives
60 * the URL to the resource. In addition, the keys <code>ARP.count</code>, <code>ARP.0</code>, <code>ARP.1</code>
61 * etc. will enumerate all URLs matching the resource name.
62 *
63 * @parameter property="clsldr.resourcePaths"
64 */
65 protected String resourcePaths;
66
67 /**
68 * Loads the classes/resources.
69 *
70 * @param outputFile The path to the properties file to generate, must not be <code>null</code>.
71 * @param classLoader The class loader to use, must not be <code>null</code>.
72 * @throws MojoExecutionException If the output file could not be created.
73 */
74 protected void execute( File outputFile, ClassLoader classLoader )
75 throws MojoExecutionException
76 {
77 getLog().info( "[MAVEN-CORE-IT-LOG] Using class loader " + classLoader );
78
79 /*
80 * NOTE: This one is a little subtle. For all properly implemented class loaders, loading a class/resource from
81 * a child class loader (with the usual parent-first delegation and no additional search path) will deliver the
82 * same result as loading directly from the parent class loader. However, Maven or better Plexus Classworlds
83 * employs custom class loaders which - as history has shown (MNG-1898) - might not always be cleanly
84 * implemented. To catch potential class loader defects, we check both the results from the original class
85 * loader and a delegating child class loader for consistency. The key point is that querying the child class
86 * loader will use a slightly different code path in the original class loader during parent delegation, thereby
87 * increasing test coverage for its implementation.
88 */
89 ClassLoader childClassLoader = new URLClassLoader( new URL[0], classLoader );
90
91 Properties loaderProperties = new Properties();
92
93 if ( classNames != null && classNames.length() > 0 )
94 {
95 String[] names = classNames.split( "," );
96 for ( String name : names )
97 {
98 getLog().info( "[MAVEN-CORE-IT-LOG] Loading class " + name );
99
100 // test ClassLoader.loadClass(String) and (indirectly) ClassLoader.loadClass(String, boolean)
101 try
102 {
103 Class type = classLoader.loadClass( name );
104 getLog().info( "[MAVEN-CORE-IT-LOG] Loaded class from " + type.getClassLoader() );
105 try
106 {
107 if ( !type.equals( childClassLoader.loadClass( name ) ) )
108 {
109 throw new ClassNotFoundException( name );
110 }
111 }
112 catch ( ClassNotFoundException cnfe )
113 {
114 getLog().error( "[MAVEN-CORE-IT-LOG] Detected class loader defect while loading " + name );
115 throw cnfe;
116 }
117 loaderProperties.setProperty( name, "" + type.hashCode() );
118
119 Method[] methods = type.getDeclaredMethods();
120 List methodNames = new ArrayList();
121 for ( Method method : methods )
122 {
123 if ( Modifier.isPublic( method.getModifiers() ) )
124 {
125 methodNames.add( method.getName() );
126 }
127 }
128 Collections.sort( methodNames );
129 StringBuilder buffer = new StringBuilder( 1024 );
130 for ( Object methodName : methodNames )
131 {
132 if ( buffer.length() > 0 )
133 {
134 buffer.append( ',' );
135 }
136 buffer.append( methodName );
137 }
138
139 loaderProperties.setProperty( name + ".methods", buffer.toString() );
140 }
141 catch ( ClassNotFoundException e )
142 {
143 // ignore, will be reported by means of missing keys in the properties file
144 getLog().info( "[MAVEN-CORE-IT-LOG] Class not available" );
145 }
146 catch ( LinkageError e )
147 {
148 // ignore, will be reported by means of missing keys in the properties file
149 getLog().info( "[MAVEN-CORE-IT-LOG] Class not linkable", e );
150 }
151 }
152 }
153
154 if ( resourcePaths != null && resourcePaths.length() > 0 )
155 {
156 String[] paths = resourcePaths.split( "," );
157 for ( String path : paths )
158 {
159 getLog().info( "[MAVEN-CORE-IT-LOG] Loading resource " + path );
160
161 // test ClassLoader.getResource()
162 URL url = classLoader.getResource( path );
163 getLog().info( "[MAVEN-CORE-IT-LOG] Loaded resource from " + url );
164 if ( url != null && !url.equals( childClassLoader.getResource( path ) ) )
165 {
166 getLog().error( "[MAVEN-CORE-IT-LOG] Detected class loader defect while getting " + path );
167 url = null;
168 }
169 if ( url != null )
170 {
171 loaderProperties.setProperty( path, url.toString() );
172 }
173
174 // test ClassLoader.getResources()
175 try
176 {
177 List urls = Collections.list( classLoader.getResources( path ) );
178 if ( !urls.equals( Collections.list( childClassLoader.getResources( path ) ) ) )
179 {
180 getLog().error( "[MAVEN-CORE-IT-LOG] Detected class loader defect while getting " + path );
181 urls = Collections.EMPTY_LIST;
182 }
183 loaderProperties.setProperty( path + ".count", "" + urls.size() );
184 for ( int j = 0; j < urls.size(); j++ )
185 {
186 loaderProperties.setProperty( path + "." + j, urls.get( j ).toString() );
187 }
188 }
189 catch ( IOException e )
190 {
191 throw new MojoExecutionException( "Resources could not be enumerated: " + path, e );
192 }
193 }
194 }
195
196 getLog().info( "[MAVEN-CORE-IT-LOG] Creating output file " + outputFile );
197
198 PropertiesUtil.write( outputFile, loaderProperties );
199
200 getLog().info( "[MAVEN-CORE-IT-LOG] Created output file " + outputFile );
201 }
202
203 }