| /******************************************************************************* |
| * Copyright (c) 2008, 2013 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.equinox.internal.transforms; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.net.URL; |
| |
| /** |
| * A proxy stream transformer is a transformer instance that relies on reflection to obtain the "getInputStream" method from an underlying object. |
| * This class is useful due to the restrictions in the builder that prevent transformer providers from directly implementing {@link StreamTransformer} due to visibility and builder issues related to referring to classes within fragments. |
| */ |
| public class ProxyStreamTransformer extends StreamTransformer { |
| |
| private Method method; |
| private Object object; |
| |
| /** |
| * Create a new proxy transformer based on the given object. |
| * @param object the object to proxy |
| * @throws SecurityException thrown if there is an issue utilizing the reflection methods |
| * @throws NoSuchMethodException thrown if the provided object does not have a "getInputStream" method that takes an {@link InputStream} and an {@link URL} |
| */ |
| public ProxyStreamTransformer(Object object) throws SecurityException, NoSuchMethodException { |
| this.object = object; |
| method = object.getClass().getMethod("getInputStream", new Class[] {InputStream.class, URL.class}); //$NON-NLS-1$ |
| Class<?> returnType = method.getReturnType(); |
| if (!returnType.equals(InputStream.class)) |
| throw new NoSuchMethodException(); |
| |
| } |
| |
| @Override |
| public InputStream getInputStream(InputStream inputStream, URL transformerUrl) throws IOException { |
| try { |
| return (InputStream) method.invoke(object, new Object[] {inputStream, transformerUrl}); |
| } catch (IllegalArgumentException | IllegalAccessException e) { |
| throw new IOException(e.getMessage()); |
| } catch (InvocationTargetException e) { |
| if (e.getCause() instanceof IOException) |
| throw (IOException) e.getCause(); |
| } |
| return null; |
| } |
| |
| /** |
| * Get the object that is being proxied. |
| * @return the object. Never <code>null</code>. |
| */ |
| public Object getTransformer() { |
| return object; |
| } |
| } |