org.codehaus.plexus.metadata.ann.AnnInvocationHandler Maven / Gradle / Ivy

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A Maven plugin to generate Plexus Components descriptors from source javadoc tags and Java class annotations.

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/*
 * Copyright (C) 2008 the original author or authors.
 *
 * 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.codehaus.plexus.metadata.ann;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Arrays;
import java.util.Map;

import org.objectweb.asm.Type;

/**
 * @author Eugene Kuleshov
 */
public class AnnInvocationHandler implements InvocationHandler {
    private final Ann ann;
    private final ClassLoader cl;
    private final Class c;

    public AnnInvocationHandler(Ann ann, ClassLoader cl, Class c) {
        this.ann = ann;
        this.cl = cl;
        this.c = c;
    }

    public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {
        String name = m.getName();

        if ("toString".equals(name)) {
            StringBuilder sb = new StringBuilder(ann.getType());
            sb.append("[");
            String sep = "";
            for (Map.Entry e : ann.getParams().entrySet()) {
                // TODO conversion for class, array, enum, and annotation types
                sb.append(sep).append(e.getKey()).append("=").append(e.getValue());
                sep = "; ";
            }
            sb.append("]");
            return sb.toString();
        }

        Object value = ann.getParams().get(name);
        if (value != null) {
            if (value instanceof Type) {
                String className = ((Type) value).getClassName();
                try {
                    return Class.forName(className, false, cl);
                } catch (ClassNotFoundException ex) {
                    if (cl instanceof URLClassLoader) {
                        URL[] urls = ((URLClassLoader) cl).getURLs();
                        throw new RuntimeException(
                                "Unable to load class " + className + " from " + Arrays.toString(urls), ex);
                    }
                    throw new RuntimeException("Unable to load class " + className + " from " + cl, ex);
                }
            }
            // TODO conversion for class, array, enum, and annotation types
            return value;
        } else {
            Method am = c.getDeclaredMethod(m.getName(), m.getParameterTypes());
            return am.getDefaultValue();
        }
    }
}