jdk/src/java.base/share/classes/sun/misc/Resource.java
changeset 36920 ce4dac5fe02a
parent 36917 02e8440be4d6
parent 36731 e4ad29a03b76
child 36921 1a3a230a7d64
equal deleted inserted replaced
36917:02e8440be4d6 36920:ce4dac5fe02a
     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 }