org.sejda.sambox.pdmodel.encryption.SecurityHandlerFactory Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of sambox Show documentation
An Apache PDFBox fork intended to be used as PDF processor for Sejda and PDFsam related projects
There is a newer version: 3.0.21
/*
 * 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 org.sejda.sambox.pdmodel.encryption;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;

/**
 * Manages security handlers for the application.
 * It follows the singleton pattern.
 * To be usable, security managers must be registered in it.
 * Security managers are retrieved by the application when necessary.
 *
 * @author Benoit Guillon
 * @author John Hewson
 */
public final class SecurityHandlerFactory
{
    /** Singleton instance */
    public static final SecurityHandlerFactory INSTANCE = new SecurityHandlerFactory();

    private final Map> nameToHandler =
            new HashMap<>();

    private final Map,
                      Class> policyToHandler =
            new HashMap<>();

    private SecurityHandlerFactory()
    {
        registerHandler(StandardSecurityHandler.FILTER,
                        StandardSecurityHandler.class,
                        StandardProtectionPolicy.class);

        registerHandler(PublicKeySecurityHandler.FILTER,
                        PublicKeySecurityHandler.class,
                        PublicKeyProtectionPolicy.class);
    }

    /**
     * Registers a security handler.
     *
     * If the security handler was already registered an exception is thrown.
     * If another handler was previously registered for the same filter name or
     * for the same policy name, an exception is thrown
     *
     * @param name the name of the filter
     * @param securityHandler security handler class to register
     * @param protectionPolicy protection policy class to register
     */
    public void registerHandler(String name,
                                Class securityHandler,
                                Class protectionPolicy)
    {
        if (nameToHandler.containsKey(name))
        {
            throw new IllegalStateException("The security handler name is already registered");
        }

        nameToHandler.put(name, securityHandler);
        policyToHandler.put(protectionPolicy, securityHandler);
    }

    /**
     * Returns a new security handler for the given protection policy, or null none is available.
     * @param policy the protection policy for which to create a security handler
     * @return a new SecurityHandler instance, or null if none is available
     */
    public SecurityHandler newSecurityHandlerForPolicy(ProtectionPolicy policy)
    {
        Class handlerClass = policyToHandler.get(policy.getClass());
        if (handlerClass == null)
        {
            return null;
        }

        Class[] argsClasses = { policy.getClass() };
        Object[] args = { policy };
        return newSecurityHandler(handlerClass, argsClasses, args);
    }

    /**
     * Returns a new security handler for the given Filter name, or null none is available.
     * @param name the Filter name from the PDF encryption dictionary
     * @return a new SecurityHandler instance, or null if none is available
     */
    public SecurityHandler newSecurityHandlerForFilter(String name)
    {
        Class handlerClass = nameToHandler.get(name);
        if (handlerClass == null)
        {
            return null;
        }

        Class[] argsClasses = { };
        Object[] args = { };
        return newSecurityHandler(handlerClass, argsClasses, args);
    }

    /* Returns a new security handler for the given parameters, or null none is available.
     *
     * @param handlerClass the handler class.
     * @param argsClasses the parameter array.
     * @param args array of objects to be passed as arguments to the constructor call.
     * @return a new SecurityHandler instance, or null if none is available.
     */
    private SecurityHandler newSecurityHandler(Class handlerClass, 
            Class[] argsClasses, Object[] args)
    {
        try
        {
            Constructor ctor =
                    handlerClass.getDeclaredConstructor(argsClasses);
            return ctor.newInstance(args);
        }
        catch(NoSuchMethodException | InvocationTargetException | InstantiationException |
              IllegalAccessException e)
        {
            // should not happen in normal operation
            throw new RuntimeException(e);
        }
    }
}