To be registered using a * {@code Loader} tag * in Tomcat's {@code Context} - * definition in the {@code server.xml} file, with the Spring-provided - * "spring-tomcat-weaver.jar" file deployed into Tomcat's "server/lib" (for Tomcat 5.x) or "lib" (for Tomcat 6.x) directory. + * definition in the {@code server.xml} file, with the Spring-provided "spring-instrument-tomcat.jar" + * file deployed into Tomcat's "server/lib" (for Tomcat 5.x) or "lib" (for Tomcat 6.x) directory. * The required configuration tag looks as follows: * *
<Loader loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"/>@@ -58,6 +59,7 @@ import org.springframework.instrument.classloading.WeavingTransformer; public class TomcatInstrumentableClassLoader extends WebappClassLoader { private static final String CLASS_SUFFIX = ".class"; + /** Use an internal WeavingTransformer */ private final WeavingTransformer weavingTransformer; @@ -101,8 +103,7 @@ public class TomcatInstrumentableClassLoader extends WebappClassLoader { */ public ClassLoader getThrowawayClassLoader() { WebappClassLoader tempLoader = new WebappClassLoader(); - // Use reflection to copy all the fields since most of them are private - // on pre-5.5 Tomcat. + // Use reflection to copy all the fields since most of them are private on pre-5.5 Tomcat. shallowCopyFieldState(this, tempLoader); return tempLoader; } @@ -111,12 +112,9 @@ public class TomcatInstrumentableClassLoader extends WebappClassLoader { @Override protected ResourceEntry findResourceInternal(String name, String path) { ResourceEntry entry = super.findResourceInternal(name, path); - // Postpone String parsing as much as possible (it is slow). if (entry != null && entry.binaryContent != null && path.endsWith(CLASS_SUFFIX)) { - String className = (name.endsWith(CLASS_SUFFIX) ? name.substring(0, name.length() - CLASS_SUFFIX.length()) - : name); - byte[] transformed = this.weavingTransformer.transformIfNecessary(className, entry.binaryContent); - entry.binaryContent = transformed; + String className = (name.endsWith(CLASS_SUFFIX) ? name.substring(0, name.length() - CLASS_SUFFIX.length()) : name); + entry.binaryContent = this.weavingTransformer.transformIfNecessary(className, entry.binaryContent); } return entry; } @@ -124,8 +122,7 @@ public class TomcatInstrumentableClassLoader extends WebappClassLoader { @Override public String toString() { StringBuilder sb = new StringBuilder(getClass().getName()); - sb.append("\r\n"); - sb.append(super.toString()); + sb.append("\r\n").append(super.toString()); return sb.toString(); } @@ -133,43 +130,23 @@ public class TomcatInstrumentableClassLoader extends WebappClassLoader { // The code below is originally taken from ReflectionUtils and optimized for // local usage. There is no dependency on ReflectionUtils to keep this class // self-contained (since it gets deployed into Tomcat's server class loader). - - /** - * Given the source object and the destination, which must be the same class - * or a subclass, copy all fields, including inherited fields. Designed to - * work on objects with public no-arg constructors. - * @throws IllegalArgumentException if arguments are incompatible or either - * is {@code null} - */ - private static void shallowCopyFieldState(final Object src, final Object dest) throws IllegalArgumentException { - if (src == null) { - throw new IllegalArgumentException("Source for field copy cannot be null"); - } - if (dest == null) { - throw new IllegalArgumentException("Destination for field copy cannot be null"); - } - Class targetClass = findCommonAncestor(src.getClass(), dest.getClass()); - + private static void shallowCopyFieldState(final WebappClassLoader src, final WebappClassLoader dest) { + Class targetClass = WebappClassLoader.class; // Keep backing up the inheritance hierarchy. do { - // Copy each field declared on this class unless it's static or - // file. Field[] fields = targetClass.getDeclaredFields(); - for (int i = 0; i < fields.length; i++) { - Field field = fields[i]; - // Skip static and final fields (the old FieldFilter) - // do not copy resourceEntries - it's a cache that holds class entries. + for (Field field : fields) { + // Do not copy resourceEntries - it's a cache that holds class entries. if (!(Modifier.isStatic(field.getModifiers()) || Modifier.isFinal(field.getModifiers()) || field.getName().equals("resourceEntries"))) { try { - // copy the field (the old FieldCallback) field.setAccessible(true); Object srcValue = field.get(src); field.set(dest, srcValue); } catch (IllegalAccessException ex) { throw new IllegalStateException( - "Shouldn't be illegal to access field '" + fields[i].getName() + "': " + ex); + "Shouldn't be illegal to access field '" + field.getName() + "': " + ex); } } } @@ -178,23 +155,4 @@ public class TomcatInstrumentableClassLoader extends WebappClassLoader { while (targetClass != null && targetClass != Object.class); } - private static Class findCommonAncestor(Class one, Class two) throws IllegalArgumentException { - Class ancestor = one; - while (ancestor != Object.class || ancestor != null) { - if (ancestor.isAssignableFrom(two)) { - return ancestor; - } - ancestor = ancestor.getSuperclass(); - } - // try the other class hierarchy - ancestor = two; - while (ancestor != Object.class || ancestor != null) { - if (ancestor.isAssignableFrom(one)) { - return ancestor; - } - ancestor = ancestor.getSuperclass(); - } - return null; - } - }