org.jboss.weld.util.ApiAbstraction Maven / Gradle / Ivy
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* JBoss, Home of Professional Open Source
* Copyright 2008, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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 org.jboss.weld.util;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import org.jboss.weld.logging.UtilLogger;
import org.jboss.weld.resources.spi.ResourceLoader;
import org.jboss.weld.resources.spi.ResourceLoadingException;
/**
* A base class for utility classes that represent annotations, classes etc
*
* @author Pete Muir
*/
public class ApiAbstraction {
private static final Class DUMMY_ANNOTATION = DummyAnnotation.class;
private static final Class DUMMY_CLASS = Dummy.class;
private ResourceLoader resourceLoader;
/**
* "Not found" annotation
*/
public @interface DummyAnnotation {
}
/**
* "Not found" class
*/
public interface Dummy {
}
/**
* "Not found" enumeration value.
*/
public static enum DummyEnum {
DUMMY_VALUE
}
/**
* Constructor
*
* @param resourceLoader The root resource loaderS
*/
public ApiAbstraction(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
/**
* Initializes an annotation class
*
* @param name The name of the annotation class
* @return The instance of the annotation. Returns a dummy if the class was
* not found
*/
@SuppressWarnings("unchecked")
protected Class annotationTypeForName(String name) {
try {
return (Class) resourceLoader.classForName(name);
} catch (ResourceLoadingException cnfe) {
return DUMMY_ANNOTATION;
}
}
/**
* Initializes a type
*
* @param name The name of the class
* @return The instance of the class. Returns a dummy if the class was not
* found.
*/
protected Class classForName(String name) {
try {
return resourceLoader.classForName(name);
} catch (ResourceLoadingException cnfe) {
return DUMMY_CLASS;
}
}
protected Object enumValue(Class clazz, String memberName) {
Preconditions.checkArgumentNotNull(memberName, "memberName");
if (!clazz.isEnum()) {
throw UtilLogger.LOG.classNotEnum(clazz);
}
try {
Field field = clazz.getField(memberName);
return field.get(null);
} catch (SecurityException e) {
return null;
} catch (NoSuchFieldException e) {
return null;
} catch (java.lang.IllegalArgumentException e) {
return null;
} catch (IllegalAccessException e) {
return null;
}
}
}