Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2017 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://oss.oracle.com/licenses/CDDL+GPL-1.1 * or LICENSE.txt. See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at LICENSE.txt. * * GPL Classpath Exception: * Oracle designates this particular file as subject to the "Classpath" * exception as provided by Oracle in the GPL Version 2 section of the License * file that accompanied this code. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ package javax.activation; import java.io.InputStream; import java.io.OutputStream; import java.io.File; import java.io.FileDescriptor; import java.io.FileNotFoundException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import com.sun.activation.registries.MimeTypeFile; /** * The FileDataSource class implements a simple DataSource object * that encapsulates a file. It provides data typing services via * a FileTypeMap object. <p> * * <b>FileDataSource Typing Semantics</b><p> * * The FileDataSource class delegates data typing of files * to an object subclassed from the FileTypeMap class. * The <code>setFileTypeMap</code> method can be used to explicitly * set the FileTypeMap for an instance of FileDataSource. If no * FileTypeMap is set, the FileDataSource will call the FileTypeMap's * getDefaultFileTypeMap method to get the System's default FileTypeMap. * * @see javax.activation.DataSource * @see javax.activation.FileTypeMap * @see javax.activation.MimetypesFileTypeMap */ public class FileDataSource implements DataSource { // keep track of original 'ref' passed in, non-null // one indicated which was passed in: private File _file = null; private FileTypeMap typeMap = null; /** * Creates a FileDataSource from a File object. <i>Note: * The file will not actually be opened until a method is * called that requires the file to be opened.</i> * * @param file the file */ public FileDataSource(File file) { _file = file; // save the file Object... } /** * Creates a FileDataSource from * the specified path name. <i>Note: * The file will not actually be opened until a method is * called that requires the file to be opened.</i> * * @param name the system-dependent file name. */ public FileDataSource(String name) { this(new File(name)); // use the file constructor } /** * This method will return an InputStream representing the * the data and will throw an IOException if it can * not do so. This method will return a new * instance of InputStream with each invocation. * * @return an InputStream */ public InputStream getInputStream() throws IOException { return new FileInputStream(_file); } /** * This method will return an OutputStream representing the * the data and will throw an IOException if it can * not do so. This method will return a new instance of * OutputStream with each invocation. * * @return an OutputStream */ public OutputStream getOutputStream() throws IOException { return new FileOutputStream(_file); } /** * This method returns the MIME type of the data in the form of a * string. This method uses the currently installed FileTypeMap. If * there is no FileTypeMap explictly set, the FileDataSource will * call the <code>getDefaultFileTypeMap</code> method on * FileTypeMap to acquire a default FileTypeMap. <i>Note: By * default, the FileTypeMap used will be a MimetypesFileTypeMap.</i> * * @return the MIME Type * @see javax.activation.FileTypeMap#getDefaultFileTypeMap */ public String getContentType() { // check to see if the type map is null? if (typeMap == null) return FileTypeMap.getDefaultFileTypeMap().getContentType(_file); else return typeMap.getContentType(_file); } /** * Return the <i>name</i> of this object. The FileDataSource * will return the file name of the object. * * @return the name of the object. * @see javax.activation.DataSource */ public String getName() { return _file.getName(); } /** * Return the File object that corresponds to this FileDataSource. * @return the File object for the file represented by this object. */ public File getFile() { return _file; } /** * Set the FileTypeMap to use with this FileDataSource * * @param map The FileTypeMap for this object. */ public void setFileTypeMap(FileTypeMap map) { typeMap = map; } }