1 files changed, 162 insertions, 0 deletions
diff --git a/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/DefaultSecHandlerFactory.java b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/DefaultSecHandlerFactory.java
new file mode 100644
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--- /dev/null
+++ b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/DefaultSecHandlerFactory.java
@@ -0,0 +1,162 @@
+package at.gv.egiz.pdfas.lib.util;/*
+ * 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.
+ */
+
+import org.apache.pdfbox.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 DefaultSecHandlerFactory
+{
+    /** Singleton instance */
+    public static final DefaultSecHandlerFactory INSTANCE = new DefaultSecHandlerFactory();
+
+    static
+    {
+
+        //Security.addProvider(new BouncyCastleProvider());
+    }
+
+    private final Map<String, Class<? extends SecurityHandler>> nameToHandler =
+            new HashMap<String, Class<? extends SecurityHandler>>();
+
+    private final Map<Class<? extends ProtectionPolicy>,
+            Class<? extends SecurityHandler>> policyToHandler =
+            new HashMap<Class<? extends ProtectionPolicy>,
+                    Class<? extends SecurityHandler>>();
+
+    private DefaultSecHandlerFactory()
+    {
+        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<? extends SecurityHandler> securityHandler,
+                                Class<? extends ProtectionPolicy> 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<? extends SecurityHandler> 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<? extends SecurityHandler> 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<? extends SecurityHandler> handlerClass,
+                                               Class<?>[] argsClasses, Object[] args)
+    {
+        try
+        {
+            Constructor<? extends SecurityHandler> ctor =
+                    handlerClass.getDeclaredConstructor(argsClasses);
+            return ctor.newInstance(args);
+        }
+        catch(NoSuchMethodException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+        catch(IllegalAccessException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+        catch(InstantiationException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+        catch(InvocationTargetException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+    }
+}