/*
 * 
 * Copyright 2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * The contents of this file are subject to the Sun Community Source
 * License v3.0/Jini Technology Specific Attachment v 1.0 (the
 * "License"). You may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * http://wwws.sun.com/software/jini/licensing/SCSL3_JiniTSA1.html.
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * The Reference Code is Jini Technology Core Platform code, v2.0. The
 * Developer of the Reference Code is Sun Microsystems, Inc.
 * 
 * Contributor(s): Sun Microsystems, Inc.
 * 
 * The contents of this file comply with the Jini Technology Core
 * Platform Compatibility Kit, v2.0A.
 * 
 * Tester(s): Sun Microsystems, Inc.
 * 
 * Test Platform(s):
 * Java 2 SDK, Standard Edition, Version 1.4.2_03 for Solaris(TM)SPARC/x86
 * Java 2 SDK, Standard Edition, Version 1.4.2_03 for Linux (Intel x86)
 * Java 2 SDK, Standard Edition, Version 1.4.2_03 for Windows (Intel Platform)
 * 
 */
package com.sun.jini.mahalo;

import com.sun.jini.landlord.ConstrainableLandlordLease;
import com.sun.jini.landlord.Landlord;
import com.sun.jini.landlord.LandlordProxyVerifier;
import net.jini.core.constraint.MethodConstraints;
import net.jini.core.constraint.RemoteMethodControl;
import net.jini.id.ReferentUuid;
import net.jini.id.Uuid;
import net.jini.security.TrustVerifier;
import net.jini.security.proxytrust.TrustEquivalence;
import java.io.Serializable;
import java.rmi.RemoteException;
import java.util.logging.Level;
import java.util.logging.Logger;

/** Defines a trust verifier for the smart proxies of a Mahalo server. */
final class ProxyVerifier implements TrustVerifier, Serializable {

    private static final long serialVersionUID = 1L;

    /** Logger for logging information about this instance */
    private static final Logger logger = 
	Logger.getLogger("net.jini.security.trust");

    /** The Mahalo server proxy. */
    private final RemoteMethodControl serverProxy;

    /**
     * The unique identifier associated with the backend server referenced
     * by the <code>serverProxy</code>, used for comparison with the IDs
     * extracted from the smart proxies being verified.
     *
     * @serial
     */
    private final Uuid proxyID;

    /**
     * Returns a verifier for the smart proxies of the specified Mahalo server
     * proxy.
     *
     * @param serverProxy the Mahalo server proxy
     * @throws UnsupportedOperationException if <code>serverProxy</code> does
     *	       not implement both {@link RemoteMethodControl} and {@link
     *	       TrustEquivalence}
     */
    ProxyVerifier(TxnManager serverProxy, Uuid proxyID) {
	if (!(serverProxy instanceof RemoteMethodControl)) {
	    throw new UnsupportedOperationException(
		"No verifier available for non-constrainable service");
	} else if (!(serverProxy instanceof TrustEquivalence)) {
	    throw new UnsupportedOperationException(
		"Verifier requires service proxy to implement " +
		"TrustEquivalence");
	} else if (proxyID == null) {
	    throw new IllegalArgumentException(
	        "Proxy id cannot be null");
	}
	this.serverProxy = (RemoteMethodControl) serverProxy;
	this.proxyID = proxyID;
    }

    /**
     * @throws NullPointerException {@inheritDoc}
     */
    public boolean isTrustedObject(Object obj, TrustVerifier.Context ctx)
	throws RemoteException
    {
	if (logger.isLoggable(Level.FINER)) {
	    logger.entering(ProxyVerifier.class.getName(), "isTrustedObject",
	        new Object[] { obj, ctx });
	}
	if (obj == null || ctx == null) {
	    throw new NullPointerException("Arguments must not be null");
	}
	RemoteMethodControl otherServerProxy;
	Uuid inputProxyID = null;
	if (obj instanceof TxnMgrProxy.ConstrainableTxnMgrProxy) {
	    otherServerProxy = (RemoteMethodControl) 
		((TxnMgrProxy)obj).backend;
	    inputProxyID = ((ReferentUuid)obj).getReferentUuid();
	} else if (obj instanceof ConstrainableLandlordLease) {
	    final LandlordProxyVerifier lpv =
		new LandlordProxyVerifier((Landlord)serverProxy, proxyID);
	    return lpv.isTrustedObject(obj, ctx);
	} else if (
	    obj instanceof TxnMgrAdminProxy.ConstrainableTxnMgrAdminProxy) {
	    otherServerProxy = (RemoteMethodControl) 
		((TxnMgrAdminProxy)obj).server;
	    inputProxyID = ((ReferentUuid)obj).getReferentUuid();
	} else if (obj instanceof TxnManager &&
	           obj instanceof RemoteMethodControl) {
	    otherServerProxy = (RemoteMethodControl)obj;
	    inputProxyID = proxyID;
	} else {
	    logger.log(Level.FINEST, "Object {0} is not a supported type",
		obj);
	    return false;
	}

	// For top-level proxies, quickly verify proxy Uuid
	if ((inputProxyID != null) &&
	    !(proxyID.equals(inputProxyID))) {
	    return false;
	}

	MethodConstraints mc = otherServerProxy.getConstraints();
	TrustEquivalence trusted =
	    (TrustEquivalence) serverProxy.setConstraints(mc);
	boolean result = trusted.checkTrustEquivalence(otherServerProxy);
	if (logger.isLoggable(Level.FINER)) {
	    logger.exiting(ProxyVerifier.class.getName(), "isTrustedObject", 
	        new Boolean(result));
	}
	return result;
    }
}
