src/main/java/com/alibaba/com/caucho/hessian/io/AnnotationInvocationHandler.java

/*
 * Copyright (c) 2001-2008 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.alibaba.com.caucho.hessian.io;

import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

/**
 * Proxy for a java annotation for known object types.
 */
public class AnnotationInvocationHandler implements InvocationHandler {
    private Class _annType;
    private HashMap<String, Object> _valueMap;

    public AnnotationInvocationHandler(Class annType,
                                       HashMap<String, Object> valueMap) {
        _annType = annType;
        _valueMap = valueMap;
    }

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

        boolean zeroArgs = args == null || args.length == 0;

        if (name.equals("annotationType") && zeroArgs)
            return _annType;
        else if (name.equals("toString") && zeroArgs)
            return toString();
        else if (name.equals("hashCode") && zeroArgs)
            return doHashCode();
        else if (name.equals("equals") && !zeroArgs && args.length == 1)
            return doEquals(args[0]);
        else if (!zeroArgs)
            return null;


        return _valueMap.get(method.getName());
    }

    public int doHashCode() {
        return 13;
    }

    public boolean doEquals(Object value) {
        if (!(value instanceof Annotation))
            return false;

        Annotation ann = (Annotation) value;

        if (!_annType.equals(ann.annotationType()))
            return false;

        return true;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();

        sb.append("@");
        sb.append(_annType.getName());
        sb.append("[");

        boolean isFirst = true;
        for (Map.Entry entry : _valueMap.entrySet()) {
            if (!isFirst)
                sb.append(", ");
            isFirst = false;

            sb.append(entry.getKey());
            sb.append("=");

            if (entry.getValue() instanceof String)
                sb.append('"').append(entry.getValue()).append('"');
            else
                sb.append(entry.getValue());
        }
        sb.append("]");

        return sb.toString();
    }
}