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.
/**
 *  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 javax.security.auth.message.config;

import java.security.AccessController;
import java.security.Permission;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.security.Security;
import java.security.SecurityPermission;
import java.util.Map;

public abstract class AuthConfigFactory {

    public static final String DEFAULT_FACTORY_SECURITY_PROPERTY =
            "authconfigprovider.factory";
    public static final String GET_FACTORY_PERMISSION_NAME =
            "getProperty.authconfigprovider.factory";
    public static final String SET_FACTORY_PERMISSION_NAME =
            "setProperty.authconfigprovider.factory";
    public static final String PROVIDER_REGISTRATION_PERMISSION_NAME =
            "setProperty.authconfigfactory.provider";

    public static final SecurityPermission getFactorySecurityPermission =
            new SecurityPermission(GET_FACTORY_PERMISSION_NAME);

    public static final SecurityPermission setFactorySecurityPermission =
            new SecurityPermission(SET_FACTORY_PERMISSION_NAME);

    public static final SecurityPermission providerRegistrationSecurityPermission =
            new SecurityPermission(PROVIDER_REGISTRATION_PERMISSION_NAME);

    private static final String DEFAULT_JASPI_AUTHCONFIGFACTORYIMPL =
            "org.apache.catalina.authenticator.jaspic.AuthConfigFactoryImpl";

    private static volatile AuthConfigFactory factory;

    public AuthConfigFactory() {
    }

    public static AuthConfigFactory getFactory() {
        checkPermission(getFactorySecurityPermission);
        if (factory != null) {
            return factory;
        }

        synchronized (AuthConfigFactory.class) {
            if (factory == null) {
                final String className = getFactoryClassName();
                try {
                    factory = AccessController.doPrivileged(
                            new PrivilegedExceptionAction<AuthConfigFactory>() {
                        @Override
                        public AuthConfigFactory run() throws ReflectiveOperationException,
                                IllegalArgumentException, SecurityException {
                            // Load this class with the same class loader as used for
                            // this class. Note that the Thread context class loader
                            // should not be used since that would trigger a memory leak
                            // in container environments.
                            Class<?> clazz = Class.forName(className);
                            return (AuthConfigFactory) clazz.getConstructor().newInstance();
                        }
                    });
                } catch (PrivilegedActionException e) {
                    Exception inner = e.getException();
                    if (inner instanceof InstantiationException) {
                        throw (SecurityException) new SecurityException("AuthConfigFactory error:" +
                                inner.getCause().getMessage()).initCause(inner.getCause());
                    } else {
                        throw (SecurityException) new SecurityException(
                                "AuthConfigFactory error: " + inner).initCause(inner);
                    }
                }
            }
        }

        return factory;
    }

    public static synchronized void setFactory(AuthConfigFactory factory) {
        checkPermission(setFactorySecurityPermission);
        AuthConfigFactory.factory = factory;
    }

    public abstract AuthConfigProvider getConfigProvider(String layer, String appContext,
            RegistrationListener listener);

    @SuppressWarnings("rawtypes") // JASPIC API uses raw types
    public abstract String registerConfigProvider(String className, Map properties, String layer,
            String appContext, String description);

    public abstract String registerConfigProvider(AuthConfigProvider provider, String layer,
            String appContext, String description);

    public abstract boolean removeRegistration(String registrationID);

    public abstract String[] detachListener(RegistrationListener listener, String layer,
            String appContext);

    public abstract String[] getRegistrationIDs(AuthConfigProvider provider);

    public abstract RegistrationContext getRegistrationContext(String registrationID);

    public abstract void refresh();

    private static void checkPermission(Permission permission) {
        SecurityManager securityManager = System.getSecurityManager();
        if (securityManager != null) {
            securityManager.checkPermission(permission);
        }
    }

    private static String getFactoryClassName() {
        String className = AccessController.doPrivileged(new PrivilegedAction<String>() {
            @Override
            public String run() {
                return Security.getProperty(DEFAULT_FACTORY_SECURITY_PROPERTY);
            }
        });

        if (className != null) {
            return className;
        }

        return DEFAULT_JASPI_AUTHCONFIGFACTORYIMPL;
    }

    public static interface RegistrationContext {

        String getMessageLayer();

        String getAppContext();

        String getDescription();

        boolean isPersistent();
    }
}