1 /*

     2  * Copyright (c) 1998, 2009, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.misc;

    27 

    28 import java.io.EOFException;

    29 import java.net.URL;

    30 import java.io.IOException;

    31 import java.io.InterruptedIOException;

    32 import java.io.InputStream;

    33 import java.security.CodeSigner;

    34 import java.util.jar.Manifest;

    35 import java.nio.ByteBuffer;

    36 import java.util.Arrays;

    37 import sun.nio.ByteBuffered;

    38 

    39 /**

    40  * This class is used to represent a Resource that has been loaded

    41  * from the class path.

    42  *

    43  * @author  David Connelly

    44  * @since   1.2

    45  */

    46 public abstract class Resource {

    47     /**

    48      * Returns the name of the Resource.

    49      */

    50     public abstract String getName();

    51 

    52     /**

    53      * Returns the URL of the Resource.

    54      */

    55     public abstract URL getURL();

    56 

    57     /**

    58      * Returns the CodeSource URL for the Resource.

    59      */

    60     public abstract URL getCodeSourceURL();

    61 

    62     /**

    63      * Returns an InputStream for reading the Resource data.

    64      */

    65     public abstract InputStream getInputStream() throws IOException;

    66 

    67     /**

    68      * Returns the length of the Resource data, or -1 if unknown.

    69      */

    70     public abstract int getContentLength() throws IOException;

    71 

    72     private InputStream cis;

    73 

    74     /* Cache result in case getBytes is called after getByteBuffer. */

    75     private synchronized InputStream cachedInputStream() throws IOException {

    76         if (cis == null) {

    77             cis = getInputStream();

    78         }

    79         return cis;

    80     }

    81 

    82     /**

    83      * Returns the Resource data as an array of bytes.

    84      */

    85     public byte[] getBytes() throws IOException {

    86         byte[] b;

    87         // Get stream before content length so that a FileNotFoundException

    88         // can propagate upwards without being caught too early

    89         InputStream in = cachedInputStream();

    90 

    91         // This code has been uglified to protect against interrupts.

    92         // Even if a thread has been interrupted when loading resources,

    93         // the IO should not abort, so must carefully retry, failing only

    94         // if the retry leads to some other IO exception.

    95 

    96         boolean isInterrupted = Thread.interrupted();

    97         int len;

    98         for (;;) {

    99             try {

   100                 len = getContentLength();

   101                 break;

   102             } catch (InterruptedIOException iioe) {

   103                 Thread.interrupted();

   104                 isInterrupted = true;

   105             }

   106         }

   107 

   108         try {

   109             b = new byte[0];

   110             if (len == -1) len = Integer.MAX_VALUE;

   111             int pos = 0;

   112             while (pos < len) {

   113                 int bytesToRead;

   114                 if (pos >= b.length) { // Only expand when there's no room

   115                     bytesToRead = Math.min(len - pos, b.length + 1024);

   116                     if (b.length < pos + bytesToRead) {

   117                         b = Arrays.copyOf(b, pos + bytesToRead);

   118                     }

   119                 } else {

   120                     bytesToRead = b.length - pos;

   121                 }

   122                 int cc = 0;

   123                 try {

   124                     cc = in.read(b, pos, bytesToRead);

   125                 } catch (InterruptedIOException iioe) {

   126                     Thread.interrupted();

   127                     isInterrupted = true;

   128                 }

   129                 if (cc < 0) {

   130                     if (len != Integer.MAX_VALUE) {

   131                         throw new EOFException("Detect premature EOF");

   132                     } else {

   133                         if (b.length != pos) {

   134                             b = Arrays.copyOf(b, pos);

   135                         }

   136                         break;

   137                     }

   138                 }

   139                 pos += cc;

   140             }

   141         } finally {

   142             try {

   143                 in.close();

   144             } catch (InterruptedIOException iioe) {

   145                 isInterrupted = true;

   146             } catch (IOException ignore) {}

   147 

   148             if (isInterrupted) {

   149                 Thread.currentThread().interrupt();

   150             }

   151         }

   152         return b;

   153     }

   154 

   155     /**

   156      * Returns the Resource data as a ByteBuffer, but only if the input stream

   157      * was implemented on top of a ByteBuffer. Return {@code null} otherwise.

   158      * @return Resource data or null.

   159      */

   160     public ByteBuffer getByteBuffer() throws IOException {

   161         InputStream in = cachedInputStream();

   162         if (in instanceof ByteBuffered) {

   163             return ((ByteBuffered)in).getByteBuffer();

   164         }

   165         return null;

   166     }

   167 

   168     /**

   169      * Returns the Manifest for the Resource, or null if none.

   170      */

   171     public Manifest getManifest() throws IOException {

   172         return null;

   173     }

   174 

   175     /**

   176      * Returns theCertificates for the Resource, or null if none.

   177      */

   178     public java.security.cert.Certificate[] getCertificates() {

   179         return null;

   180     }

   181 

   182     /**

   183      * Returns the code signers for the Resource, or null if none.

   184      */

   185     public CodeSigner[] getCodeSigners() {

   186         return null;

   187     }

   188 }