001/*
002 * JDrupes Builder
003 * Copyright (C) 2025 Michael N. Lipp
004 * 
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
017 */
018
019package org.jdrupes.builder.core;
020
021import java.lang.reflect.InvocationHandler;
022import java.lang.reflect.InvocationTargetException;
023import java.lang.reflect.Method;
024import java.lang.reflect.Proxy;
025import org.jdrupes.builder.api.Proxyable;
026
027/// A [InvocationHandler] that simply forwards all invocations to the
028/// proxied object.
029///
030public class ForwardingHandler implements InvocationHandler {
031
032    private final Object proxied;
033
034    /// Instantiates a new forwarding handler.
035    ///
036    /// @param proxied the proxied object
037    ///
038    public ForwardingHandler(Object proxied) {
039        this.proxied = proxied;
040    }
041
042    @Override
043    public Object invoke(Object proxy, Method method, Object[] args)
044            throws Throwable {
045        if ("equals".equals(method.getName())
046            && Proxy.isProxyClass(args[0].getClass())
047            && args[0] instanceof Proxyable other) {
048            return method.invoke(proxied, other.backing());
049        }
050        try {
051            return method.invoke(proxied, args);
052        } catch (InvocationTargetException e) {
053            throw e.getCause();
054        }
055    }
056
057}