Anonymous avatar Anonymous committed 6e411d0

Fixed misspellings, bad logging, added classloader scanning util from
Stripes

git-svn-id: http://svn.opensymphony.com/svn/xwork/trunk@1181 e221344d-f017-0410-9bd5-d282ab1896d7

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Files changed (3)

src/java/com/opensymphony/xwork2/config/impl/DefaultConfiguration.java

                 } 
             } else {
                 throw new ConfigurationException("The package name '" + name 
-                        + "' at locattion "+packageContext.getLocation()
+                        + "' at location "+packageContext.getLocation()
                         + " is already been used by another package at location " + check.getLocation(),
                         packageContext);
             }

src/java/com/opensymphony/xwork2/config/providers/XmlConfigurationProvider.java

         Location location = DomHelper.getLocationObject(actionElement);
 
         if (location == null) {
-            System.out.println("location null for "+className);
+            LOG.warn("location null for "+className);
         }
         //methodName should be null if it's not set
         methodName = (methodName.trim().length() > 0) ? methodName.trim() : null;

src/java/com/opensymphony/xwork2/util/ResolverUtil.java

+/* Copyright 2005-2006 Tim Fennell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.opensymphony.xwork2.util;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.lang.annotation.Annotation;
+import java.net.URL;
+import java.net.URLDecoder;
+import java.util.Enumeration;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.jar.JarEntry;
+import java.util.jar.JarInputStream;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * <p>ResolverUtil is used to locate classes that are available in the/a class path and meet
+ * arbitrary conditions. The two most common conditions are that a class implements/extends
+ * another class, or that is it annotated with a specific annotation. However, through the use
+ * of the {@link Test} class it is possible to search using arbitrary conditions.</p>
+ *
+ * <p>A ClassLoader is used to locate all locations (directories and jar files) in the class
+ * path that contain classes within certain packages, and then to load those classes and
+ * check them. By default the ClassLoader returned by
+ *  {@code Thread.currentThread().getContextClassLoader()} is used, but this can be overridden
+ * by calling {@link #setClassLoader(ClassLoader)} prior to invoking any of the {@code find()}
+ * methods.</p>
+ *
+ * <p>General searches are initiated by calling the
+ * {@link #find(com.opensymphony.xwork2.util.ResolverUtil.Test, String)} ()} method and supplying
+ * a package name and a Test instance. This will cause the named package <b>and all sub-packages</b>
+ * to be scanned for classes that meet the test. There are also utility methods for the common
+ * use cases of scanning multiple packages for extensions of particular classes, or classes
+ * annotated with a specific annotation.</p>
+ *
+ * <p>The standard usage pattern for the ResolverUtil class is as follows:</p>
+ *
+ *<pre>
+ *ResolverUtil&lt;ActionBean&gt; resolver = new ResolverUtil&lt;ActionBean&gt;();
+ *resolver.findImplementation(ActionBean.class, pkg1, pkg2);
+ *resolver.find(new CustomTest(), pkg1);
+ *resolver.find(new CustomTest(), pkg2);
+ *Collection&lt;ActionBean&gt; beans = resolver.getClasses();
+ *</pre> 
+ *
+ * <p>This class was copied from Stripes - http://stripes.mc4j.org/confluence/display/stripes/Home
+ * </p>
+ * 
+ * @author Tim Fennell
+ */
+public class ResolverUtil<T> {
+    /** An instance of Log to use for logging in this class. */
+    private static final Log log = LogFactory.getLog(ResolverUtil.class);
+
+    /**
+     * A simple interface that specifies how to test classes to determine if they
+     * are to be included in the results produced by the ResolverUtil.
+     */
+    public static interface Test {
+        /**
+         * Will be called repeatedly with candidate classes. Must return True if a class
+         * is to be included in the results, false otherwise.
+         */
+        boolean matches(Class type);
+    }
+
+    /**
+     * A Test that checks to see if each class is assignable to the provided class. Note
+     * that this test will match the parent type itself if it is presented for matching.
+     */
+    public static class IsA implements Test {
+        private Class parent;
+
+        /** Constructs an IsA test using the supplied Class as the parent class/interface. */
+        public IsA(Class parentType) { this.parent = parentType; }
+
+        /** Returns true if type is assignable to the parent type supplied in the constructor. */
+        public boolean matches(Class type) {
+            return type != null && parent.isAssignableFrom(type);
+        }
+
+        @Override public String toString() {
+            return "is assignable to " + parent.getSimpleName();
+        }
+    }
+    
+    /**
+     * A Test that checks to see if each class name ends with the provided suffix.
+     */
+    public static class NameEndsWith implements Test {
+        private String suffix;
+
+        /** Constructs a NameEndsWith test using the supplied suffix. */
+        public NameEndsWith(String suffix) { this.suffix = suffix; }
+
+        /** Returns true if type name ends with the suffix supplied in the constructor. */
+        public boolean matches(Class type) {
+            return type != null && type.getName().endsWith(suffix);
+        }
+
+        @Override public String toString() {
+            return "ends with the suffix " + suffix;
+        }
+    }
+
+    /**
+     * A Test that checks to see if each class is annotated with a specific annotation. If it
+     * is, then the test returns true, otherwise false.
+     */
+    public static class AnnotatedWith implements Test {
+        private Class<? extends Annotation> annotation;
+
+        /** Construts an AnnotatedWith test for the specified annotation type. */
+        public AnnotatedWith(Class<? extends Annotation> annotation) { this.annotation = annotation; }
+
+        /** Returns true if the type is annotated with the class provided to the constructor. */
+        public boolean matches(Class type) {
+            return type != null && type.isAnnotationPresent(annotation);
+        }
+
+        @Override public String toString() {
+            return "annotated with @" + annotation.getSimpleName();
+        }
+    }
+
+    /** The set of matches being accumulated. */
+    private Set<Class<? extends T>> matches = new HashSet<Class<?extends T>>();
+
+    /**
+     * The ClassLoader to use when looking for classes. If null then the ClassLoader returned
+     * by Thread.currentThread().getContextClassLoader() will be used.
+     */
+    private ClassLoader classloader;
+
+    /**
+     * Provides access to the classes discovered so far. If no calls have been made to
+     * any of the {@code find()} methods, this set will be empty.
+     *
+     * @return the set of classes that have been discovered.
+     */
+    public Set<Class<? extends T>> getClasses() {
+        return matches;
+    }
+
+    /**
+     * Returns the classloader that will be used for scanning for classes. If no explicit
+     * ClassLoader has been set by the calling, the context class loader will be used.
+     *
+     * @return the ClassLoader that will be used to scan for classes
+     */
+    public ClassLoader getClassLoader() {
+        return classloader == null ? Thread.currentThread().getContextClassLoader() : classloader;
+    }
+
+    /**
+     * Sets an explicit ClassLoader that should be used when scanning for classes. If none
+     * is set then the context classloader will be used.
+     *
+     * @param classloader a ClassLoader to use when scanning for classes
+     */
+    public void setClassLoader(ClassLoader classloader) { this.classloader = classloader; }
+
+    /**
+     * Attempts to discover classes that are assignable to the type provided. In the case
+     * that an interface is provided this method will collect implementations. In the case
+     * of a non-interface class, subclasses will be collected.  Accumulated classes can be
+     * accessed by calling {@link #getClasses()}.
+     *
+     * @param parent the class of interface to find subclasses or implementations of
+     * @param packageNames one or more package names to scan (including subpackages) for classes
+     */
+    public void findImplementations(Class parent, String... packageNames) {
+        if (packageNames == null) return;
+
+        Test test = new IsA(parent);
+        for (String pkg : packageNames) {
+            find(test, pkg);
+        }
+    }
+    
+    /**
+     * Attempts to discover classes who's name ends with the provided suffix. Accumulated classes can be
+     * accessed by calling {@link #getClasses()}.
+     *
+     * @param suffix The class name suffix to match
+     * @param packageNames one or more package names to scan (including subpackages) for classes
+     */
+    public void findSuffix(String suffix, String... packageNames) {
+        if (packageNames == null) return;
+
+        Test test = new NameEndsWith(suffix);
+        for (String pkg : packageNames) {
+            find(test, pkg);
+        }
+    }
+
+    /**
+     * Attempts to discover classes that are annotated with to the annotation. Accumulated
+     * classes can be accessed by calling {@link #getClasses()}.
+     *
+     * @param annotation the annotation that should be present on matching classes
+     * @param packageNames one or more package names to scan (including subpackages) for classes
+     */
+    public void findAnnotated(Class<? extends Annotation> annotation, String... packageNames) {
+        if (packageNames == null) return;
+
+        Test test = new AnnotatedWith(annotation);
+        for (String pkg : packageNames) {
+            find(test, pkg);
+        }
+    }
+
+    /**
+     * Scans for classes starting at the package provided and descending into subpackages.
+     * Each class is offered up to the Test as it is discovered, and if the Test returns
+     * true the class is retained.  Accumulated classes can be fetched by calling
+     * {@link #getClasses()}.
+     *
+     * @param test an instance of {@link Test} that will be used to filter classes
+     * @param packageName the name of the package from which to start scanning for
+     *        classes, e.g. {@code net.sourceforge.stripes}
+     */
+    public void find(Test test, String packageName) {
+        packageName = packageName.replace('.', '/');
+        ClassLoader loader = getClassLoader();
+        Enumeration<URL> urls;
+
+        try {
+            urls = loader.getResources(packageName);
+        }
+        catch (IOException ioe) {
+            log.warn("Could not read package: " + packageName, ioe);
+            return;
+        }
+
+        while (urls.hasMoreElements()) {
+            try {
+                String urlPath = urls.nextElement().getFile();
+                urlPath = URLDecoder.decode(urlPath, "UTF-8");
+
+                // If it's a file in a directory, trim the stupid file: spec
+                if ( urlPath.startsWith("file:") ) {
+                    urlPath = urlPath.substring(5);
+                }
+
+                // Else it's in a JAR, grab the path to the jar
+                if (urlPath.indexOf('!') > 0) {
+                    urlPath = urlPath.substring(0, urlPath.indexOf('!'));
+                }
+
+                log.info("Scanning for classes in [" + urlPath + "] matching criteria: " + test);
+                File file = new File(urlPath);
+                if ( file.isDirectory() ) {
+                    loadImplementationsInDirectory(test, packageName, file);
+                }
+                else {
+                    loadImplementationsInJar(test, packageName, file);
+                }
+            }
+            catch (IOException ioe) {
+                log.warn("could not read entries", ioe);
+            }
+        }
+    }
+
+
+    /**
+     * Finds matches in a physical directory on a filesystem.  Examines all
+     * files within a directory - if the File object is not a directory, and ends with <i>.class</i>
+     * the file is loaded and tested to see if it is acceptable according to the Test.  Operates
+     * recursively to find classes within a folder structure matching the package structure.
+     *
+     * @param test a Test used to filter the classes that are discovered
+     * @param parent the package name up to this directory in the package hierarchy.  E.g. if
+     *        /classes is in the classpath and we wish to examine files in /classes/org/apache then
+     *        the values of <i>parent</i> would be <i>org/apache</i>
+     * @param location a File object representing a directory
+     */
+    private void loadImplementationsInDirectory(Test test, String parent, File location) {
+        File[] files = location.listFiles();
+        StringBuilder builder = null;
+
+        for (File file : files) {
+            builder = new StringBuilder(100);
+            builder.append(parent).append("/").append(file.getName());
+            String packageOrClass = ( parent == null ? file.getName() : builder.toString() );
+
+            if (file.isDirectory()) {
+                loadImplementationsInDirectory(test, packageOrClass, file);
+            }
+            else if (file.getName().endsWith(".class")) {
+                addIfMatching(test, packageOrClass);
+            }
+        }
+    }
+
+    /**
+     * Finds matching classes within a jar files that contains a folder structure
+     * matching the package structure.  If the File is not a JarFile or does not exist a warning
+     * will be logged, but no error will be raised.
+     *
+     * @param test a Test used to filter the classes that are discovered
+     * @param parent the parent package under which classes must be in order to be considered
+     * @param jarfile the jar file to be examined for classes
+     */
+    private void loadImplementationsInJar(Test test, String parent, File jarfile) {
+
+        try {
+            JarEntry entry;
+            JarInputStream jarStream = new JarInputStream(new FileInputStream(jarfile));
+
+            while ( (entry = jarStream.getNextJarEntry() ) != null) {
+                String name = entry.getName();
+                if (!entry.isDirectory() && name.startsWith(parent) && name.endsWith(".class")) {
+                    addIfMatching(test, name);
+                }
+            }
+        }
+        catch (IOException ioe) {
+            log.error("Could not search jar file '" + jarfile + "' for classes matching criteria: " +
+                      test + " due to an IOException", ioe);
+        }
+    }
+
+    /**
+     * Add the class designated by the fully qualified class name provided to the set of
+     * resolved classes if and only if it is approved by the Test supplied.
+     *
+     * @param test the test used to determine if the class matches
+     * @param fqn the fully qualified name of a class
+     */
+    protected void addIfMatching(Test test, String fqn) {
+        try {
+            String externalName = fqn.substring(0, fqn.indexOf('.')).replace('/', '.');
+            ClassLoader loader = getClassLoader();
+            if (log.isDebugEnabled()) {
+                log.debug("Checking to see if class " + externalName + " matches criteria [" + test + "]");
+            }
+
+            Class type = loader.loadClass(externalName);
+            if (test.matches(type) ) {
+                matches.add( (Class<T>) type);
+            }
+        }
+        catch (Throwable t) {
+            log.warn("Could not examine class '" + fqn + "' due to a " +
+                     t.getClass().getName() + " with message: " + t.getMessage());
+        }
+    }
+}
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