Java tutorial
/* * 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.apache.wicket.resource; import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; import java.nio.file.Path; import java.nio.file.Paths; import java.util.Iterator; import java.util.Map; import java.util.ServiceLoader; import org.apache.wicket.WicketRuntimeException; import org.apache.wicket.request.resource.IResource; import org.apache.wicket.request.resource.ResourceReference; /** * This resource reference is used to provide a reference to a resource based on Java NIO FileSystem * API.<br> * <br> * To implement a mime type detection refer to the documentation of * {@link java.nio.file.Files#probeContentType(Path)} and provide an implementation for * java.nio.file.spi.FileTypeDetector in the META-INF/services folder for jars or in the * /WEB-INF/classes/META-INF/services folder for webapps<br> * <br> * You can optionally override {@link #getFileSystemResource()} to provide an inline mime type * detection, which is preferred to the default detection.<br> * <br> * Example: * * <pre> * <code> * Path path = FileSystemResourceReference.getPath(URI.create("jar:file:///folder/file.zip!/folderInZip/video.mp4")); * add(new Video("video", new FileSystemResourceReference(path))); * </code> * </pre> * * Example 2: * * <pre> * <code> * mountResource("/filecontent/${name}", new FileSystemResourceReference("filesystem") * { * private static final long serialVersionUID = 1L; * * {@literal @}Override * public IResource getResource() * { * return new FileSystemResource() * { * private static final long serialVersionUID = 1L; * * protected ResourceResponse newResourceResponse(Attributes attributes) * { * try * { * String name = attributes.getParameters().get("name").toString(""); * URI uri = URI.create( * "jar:file:////folder/example.zip!/zipfolder/" + name); * return createResourceResponse( * FileSystemResourceReference.getPath(uri)); * } * catch (IOException | URISyntaxException e) * { * throw new WicketRuntimeException("Error while reading the file.", e); * } * }; * }; * } * }); * </code> * </pre> * * @author Tobias Soloschenko */ public class FileSystemResourceReference extends ResourceReference { private static final long serialVersionUID = 1L; private Path path; /** * Creates a file system resource reference based on the given path * * @param name * the name of the resource reference to expose data * @param path * the path to create the resource reference */ public FileSystemResourceReference(String name, Path path) { super(name); this.path = path; } /** * Creates a file system resource reference based on the given name * * @param name * the name of the resource reference * */ public FileSystemResourceReference(String name) { super(name); } /** * Creates a file system resource reference based on the given scope and name * * @param scope * the scope as class * @param name * the name of the resource reference * */ public FileSystemResourceReference(Class<?> scope, String name) { super(scope, name); } /** * Creates a new {@link org.apache.wicket.markup.html.media.FileSystemResource} and applies the * path to it. */ @Override public IResource getResource() { return getFileSystemResource(); } /** * Gets the file system resource to be used for the resource reference * * @return the file system resource to be used for the resource reference */ protected FileSystemResource getFileSystemResource() { if (path == null) { throw new WicketRuntimeException( "Please override #getResource() and provide a path if using a constructor which doesn't take one as argument."); } return new FileSystemResource(path); } /** * Creates a path and a file system (if required) based on the given URI * * @param uri * the URI to create the file system and the path of * @param env * the environment parameter to create the file system with * @return the path of the file in the file system */ public static Path getPath(URI uri, Map<String, String> env) { Iterator<FileSystemPathService> pathServiceIterator = ServiceLoader.load(FileSystemPathService.class) .iterator(); while (pathServiceIterator.hasNext()) { FileSystemPathService pathService = pathServiceIterator.next(); if (pathService.isResponsible(uri)) { Path fileSystemPath = pathService.getPath(uri, env); if (fileSystemPath != null) { return fileSystemPath; } } } // fall back to just get the path from the URI return Paths.get(uri); } /** * Creates a path and a file system (if required) based on the given URI * * @param uri * the URI to create the file system and the path of * @return the path of the file in the file system * @throws IOException * if the file system could'nt be created * @throws URISyntaxException * if the URI has no valid syntax */ public static Path getPath(URI uri) throws IOException, URISyntaxException { return getPath(uri, null); } }