org.apache.bval.jsr.xml.AnnotationProxyBuilder Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of openejb-lite
There is a newer version: 10.0.0-M3
/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.apache.bval.jsr.xml;

import org.apache.bval.cdi.EmptyAnnotationLiteral;
import org.apache.bval.jsr.ConstraintAnnotationAttributes;
import org.apache.bval.util.reflection.Reflection;
import org.apache.commons.weaver.privilizer.Privileged;
import org.apache.commons.weaver.privilizer.Privilizing;
import org.apache.commons.weaver.privilizer.Privilizing.CallTo;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import javax.enterprise.util.AnnotationLiteral;
import javax.validation.Payload;
import javax.validation.Valid;
import javax.validation.ValidationException;
import javax.validation.groups.ConvertGroup;

/**
 * Description: Holds the information and creates an annotation proxy during xml
 * parsing of validation mapping constraints. 

 */
@Privilizing(@CallTo(Reflection.class))
public final class AnnotationProxyBuilder {
    private static final ConcurrentMap, Method[]> METHODS_CACHE = new ConcurrentHashMap, Method[]>();

    private final Class type;
    private final Map elements = new HashMap();
    private final Method[] methods;

    /**
     * Create a new AnnotationProxyBuilder instance.
     *
     * @param annotationType
     */
    public AnnotationProxyBuilder(final Class annotationType) {
        this.type = annotationType;
        this.methods = findMethods(annotationType);
    }

    public static  Method[] findMethods(final Class annotationType) {
        if (annotationType.getName().startsWith("javax.validation.constraints.")) { // cache built-in constraints only to avoid mem leaks
            Method[] mtd = METHODS_CACHE.get(annotationType);
            if (mtd == null) {
                final Method[] value = Reflection.getDeclaredMethods(annotationType);
                mtd = METHODS_CACHE.putIfAbsent(annotationType, value);
                if (mtd == null) {
                    mtd = value;
                }
            }
            return mtd;
        }
        return Reflection.getDeclaredMethods(annotationType);
    }

    /**
     * Create a new AnnotationProxyBuilder instance.
     *
     * @param annotationType
     * @param elements
     */
    public AnnotationProxyBuilder(Class annotationType, Map elements) {
        this(annotationType);
        for (Map.Entry entry : elements.entrySet()) {
            this.elements.put(entry.getKey(), entry.getValue());
        }
    }

    /**
     * Create a builder initially configured to create an annotation equivalent
     * to annot.
     * 
     * @param annot Annotation to be replicated.
     */
    @SuppressWarnings("unchecked")
    public AnnotationProxyBuilder(A annot) {
        this((Class) annot.annotationType());
        // Obtain the "elements" of the annotation
        for (Method m : methods) {
            final boolean mustUnset = Reflection.setAccessible(m, true);
            try {
                Object value = m.invoke(annot);
                this.elements.put(m.getName(), value);
            } catch (Exception e) {
                throw new ValidationException("Cannot access annotation " + annot + " element: " + m.getName(), e);
            } finally {
                if (mustUnset) {
                    Reflection.setAccessible(m, false);
                }
            }
        }
    }

    public Method[] getMethods() {
        return methods;
    }

    /**
     * Add an element to the configuration.
     *
     * @param elementName
     * @param value
     */
    public void putValue(String elementName, Object value) {
        elements.put(elementName, value);
    }

    /**
     * Get the specified element value from the current configuration.
     *
     * @param elementName
     * @return Object value
     */
    public Object getValue(String elementName) {
        return elements.get(elementName);
    }

    /**
     * Learn whether a given element has been configured.
     *
     * @param elementName
     * @return true if an elementName element is found
     *         on this annotation
     */
    public boolean contains(String elementName) {
        return elements.containsKey(elementName);
    }

    /**
     * Get the number of configured elements.
     *
     * @return int
     */
    public int size() {
        return elements.size();
    }

    /**
     * Get the configured Annotation type.
     *
     * @return Class
     */
    public Class getType() {
        return type;
    }

    /**
     * Configure the well-known JSR303 "message" element.
     *
     * @param message
     */
    public void setMessage(String message) {
        ConstraintAnnotationAttributes.MESSAGE.put(elements, message);
    }

    /**
     * Configure the well-known JSR303 "groups" element.
     *
     * @param groups
     */
    public void setGroups(Class[] groups) {
        ConstraintAnnotationAttributes.GROUPS.put(elements, groups);
    }

    /**
     * Configure the well-known JSR303 "payload" element.
     * 
     * @param payload
     */
    public void setPayload(Class[] payload) {
        ConstraintAnnotationAttributes.PAYLOAD.put(elements, payload);
    }

    /**
     * Create the annotation represented by this builder.
     *
     * @return {@link Annotation}
     */
    public A createAnnotation() {
        final ClassLoader classLoader = Reflection.getClassLoader(getType());
        @SuppressWarnings("unchecked")
        final Class proxyClass = (Class) Proxy.getProxyClass(classLoader, getType());
        final InvocationHandler handler = new AnnotationProxy(this);
        return doCreateAnnotation(proxyClass, handler);
    }

    @Privileged
    private A doCreateAnnotation(final Class proxyClass, final InvocationHandler handler) {
        try {
            Constructor constructor = proxyClass.getConstructor(InvocationHandler.class);
            Reflection.setAccessible(constructor, true); // java 8
            return constructor.newInstance(handler);
        } catch (Exception e) {
            throw new ValidationException("Unable to create annotation for configured constraint", e);
        }
    }

    public static final class ValidAnnotation extends EmptyAnnotationLiteral implements Valid {
        private static final long serialVersionUID = 1L;

        public static final ValidAnnotation INSTANCE = new ValidAnnotation();
    }

    public static final class ConvertGroupAnnotation extends AnnotationLiteral implements ConvertGroup {
        private static final long serialVersionUID = 1L;

        private final Class from;
        private final Class to;

        public ConvertGroupAnnotation(final Class from, final Class to) {
            this.from = from;
            this.to = to;
        }

        @Override
        public Class from() {
            return from;
        }

        @Override
        public Class to() {
            return to;
        }
    }
}