aboutsummaryrefslogtreecommitdiffstats
path: root/src/java/com/jogamp/common/util/IOUtil.java
blob: ed74fa2036124746906a3b5557d89b71c2bbe038 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
/**
 * Copyright 2010 JogAmp Community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and should not be interpreted as representing official policies, either expressed
 * or implied, of JogAmp Community.
 */

package com.jogamp.common.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.AccessControlContext;
import java.lang.reflect.Constructor;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.ByteBuffer;

import jogamp.common.Debug;
import jogamp.common.os.AndroidUtils;

import com.jogamp.common.net.AssetURLContext;
import com.jogamp.common.nio.Buffers;
import com.jogamp.common.os.MachineDescription;
import com.jogamp.common.os.Platform;

public class IOUtil {
    public static final boolean DEBUG = Debug.debug("IOUtil");
    
    /** Std. temporary directory property key <code>java.io.tmpdir</code> */
    public static final String java_io_tmpdir_propkey = "java.io.tmpdir";

    private static final Constructor<?> fosCtor;
    
    static {
        Constructor<?> _fosCtor;
        try {
            _fosCtor = ReflectionUtil.getConstructor("java.io.FileOutputStream", new Class<?>[] { File.class }, IOUtil.class.getClassLoader());
        } catch (Throwable t) {
            if(DEBUG) { t.printStackTrace(); }
            _fosCtor = null;
        }
        fosCtor = _fosCtor;
    }
    
    private IOUtil() {}
    
    /***
     * 
     * STREAM COPY STUFF
     *  
     */
    
    /**
     * Copy the specified URL resource to the specified output file. The total
     * number of bytes written is returned. Both streams are closed upon completion.
     * 
     * @param conn the open URLConnection 
     * @param outFile the destination
     * @return
     * @throws IOException
     */
    public static int copyURLConn2File(URLConnection conn, File outFile) throws IOException {
        conn.connect();  // redundant     

        int totalNumBytes = 0;
        InputStream in = new BufferedInputStream(conn.getInputStream());
        try {
            totalNumBytes = copyStream2File(in, outFile, conn.getContentLength());
        } finally {
            in.close();
        }
        return totalNumBytes;
    }

    /**
     * Copy the specified input stream to the specified output file. The total
     * number of bytes written is returned. Both streams are closed upon completion.
     * 
     * @param in the source 
     * @param outFile the destination
     * @param totalNumBytes informal number of expected bytes, maybe used for user feedback while processing. -1 if unknown 
     * @return
     * @throws IOException
     */
    public static int copyStream2File(InputStream in, File outFile, int totalNumBytes) throws IOException {
        OutputStream out = new BufferedOutputStream(new FileOutputStream(outFile));
        try {
            totalNumBytes = copyStream2Stream(in, out, totalNumBytes);
        } finally {
            out.close();
        }
        return totalNumBytes;
    }

    /**
     * Copy the specified input stream to the specified output stream. The total
     * number of bytes written is returned.
     * 
     * @param in the source 
     * @param out the destination
     * @param totalNumBytes informal number of expected bytes, maybe used for user feedback while processing. -1 if unknown 
     * @return
     * @throws IOException
     */
    public static int copyStream2Stream(InputStream in, OutputStream out, int totalNumBytes) throws IOException {
        final byte[] buf = new byte[Platform.getMachineDescription().pageSizeInBytes()];
        int numBytes = 0;
        while (true) {
            int count;
            if ((count = in.read(buf)) == -1) {
                break;
            }
            out.write(buf, 0, count);
            numBytes += count;
        }
        return numBytes;
    }

    /**
     * Copy the specified input stream to a byte array, which is being returned.
     */
    public static byte[] copyStream2ByteArray(InputStream stream) throws IOException {
        // FIXME: Shall enforce a BufferedInputStream ?
        if( !(stream instanceof BufferedInputStream) ) {
            stream = new BufferedInputStream(stream);
        }
        int totalRead = 0;
        int avail = stream.available();
        byte[] data = new byte[avail];
        int numRead = 0;
        do {
            if (totalRead + avail > data.length) {
                final byte[] newData = new byte[totalRead + avail];
                System.arraycopy(data, 0, newData, 0, totalRead);
                data = newData;
            }
            numRead = stream.read(data, totalRead, avail);
            if (numRead >= 0) {
                totalRead += numRead;
            }
            avail = stream.available();
        } while (avail > 0 && numRead >= 0);

        // just in case the announced avail > totalRead
        if (totalRead != data.length) {
            final byte[] newData = new byte[totalRead];
            System.arraycopy(data, 0, newData, 0, totalRead);
            data = newData;
        }
        return data;
    }

    /**
     * Copy the specified input stream to a NIO ByteBuffer w/ native byte order, which is being returned.
     * <p>The implementation creates the ByteBuffer w/ {@link #copyStream2ByteArray(InputStream)}'s returned byte array.</p>
     */
    public static ByteBuffer copyStream2ByteBuffer(InputStream stream) throws IOException {
        // FIXME: Shall enforce a BufferedInputStream ?
        if( !(stream instanceof BufferedInputStream) ) {
            stream = new BufferedInputStream(stream);
        }
        int avail = stream.available();
        final MachineDescription machine = Platform.getMachineDescription(); 
        ByteBuffer data = Buffers.newDirectByteBuffer( machine.pageAlignedSize(avail) );
        byte[] chunk = new byte[machine.pageSizeInBytes()];
        int chunk2Read = Math.min(machine.pageSizeInBytes(), avail);
        int numRead = 0;
        do {
            if (avail > data.remaining()) {
                final ByteBuffer newData = Buffers.newDirectByteBuffer(
                                               machine.pageAlignedSize(data.position() + avail) );
                newData.put(data);
                data = newData;
            }
            
            numRead = stream.read(chunk, 0, chunk2Read);
            if (numRead >= 0) {
                data.put(chunk, 0, numRead);
            }
            avail = stream.available();
            chunk2Read = Math.min(machine.pageSizeInBytes(), avail);
        } while (avail > 0 && numRead >= 0);

        data.flip();
        return data;
    }

    /***
     * 
     * RESOURCE / FILE NAME STUFF
     *  
     */
    
    /**
     * 
     * @param path
     * @param startWithSlash
     * @param endWithSlash
     * @return
     * @throws RuntimeException if final path is empty or has no parent directory available while resolving <code>../</code> 
     */
    public static String slashify(String path, boolean startWithSlash, boolean endWithSlash) throws RuntimeException {
        String p = path.replace('\\', '/'); // unify file seperator     
        if (startWithSlash && !p.startsWith("/")) {
            p = "/" + p;
        }
        if (endWithSlash && !p.endsWith("/")) {
            p = p + "/";
        }
        try {
            return cleanPathString(p);
        } catch (MalformedURLException e) {
            throw new RuntimeException(e);
        }        
    }
    
    /** Using the proper advertised conversion via File -> URI -> URL */
    public static URL toURL(File file) throws MalformedURLException {
        return file.toURI().toURL();
    }
    
    /** Using the simple conversion via File -> URL, assuming proper characters. */
    public static URL toURLSimple(File file) throws MalformedURLException {
        return new URL("file", "", slashify(file.getAbsolutePath(), true, file.isDirectory()));        
    }
    
    public static URL toURLSimple(String protocol, String file, boolean isDirectory) throws MalformedURLException {
        return new URL(protocol, "", slashify(file, true, isDirectory));        
    }
    
    /**
     * Returns the lowercase suffix of the given file name (the text
     * after the last '.' in the file name). Returns null if the file
     * name has no suffix. Only operates on the given file name;
     * performs no I/O operations.
     *
     * @param file name of the file
     * @return lowercase suffix of the file name
     * @throws NullPointerException if file is null
     */

    public static String getFileSuffix(File file) {
        return getFileSuffix(file.getName());
    }

    /**
     * Returns the lowercase suffix of the given file name (the text
     * after the last '.' in the file name). Returns null if the file
     * name has no suffix. Only operates on the given file name;
     * performs no I/O operations.
     *
     * @param filename name of the file
     * @return lowercase suffix of the file name
     * @throws NullPointerException if filename is null
     */
    public static String getFileSuffix(String filename) {
        int lastDot = filename.lastIndexOf('.');
        if (lastDot < 0) {
            return null;
        }
        return toLowerCase(filename.substring(lastDot + 1));
    }

    /***
     * @param file
     * @param allowOverwrite
     * @return outputStream The resulting output stream
     * @throws IOException if the file already exists and <code>allowOverwrite</code> is false, 
     *                     the class <code>java.io.FileOutputStream</code> is not accessible or
     *                     the user does not have sufficient rights to access the local filesystem. 
     */
    public static FileOutputStream getFileOutputStream(File file, boolean allowOverwrite) throws IOException {
        if(null == fosCtor) {
            throw new IOException("Cannot open file (" + file + ") for writing, feature not available.");
        }
        if (file.exists() && !allowOverwrite) {
            throw new IOException("File already exists (" + file + ") and overwrite=false");
        }
        try {
            return (FileOutputStream) fosCtor.newInstance(new Object[] { file });
        } catch (Exception e) {
            throw new IOException("error opening " + file + " for write. ", e);
        }
    }
    
    public static String getClassFileName(String clazzBinName) throws IOException {
        // or return clazzBinName.replace('.', File.pathSeparatorChar) + ".class"; ?            
        return clazzBinName.replace('.', '/') + ".class";            
    }
    
    /**
     * @param clazzBinName com.jogamp.common.util.cache.TempJarCache 
     * @param cl
     * @return jar:file:/usr/local/projects/JOGL/gluegen/build-x86_64/gluegen-rt.jar!/com/jogamp/common/util/cache/TempJarCache.class
     * @throws IOException
     */
    public static URL getClassURL(String clazzBinName, ClassLoader cl) throws IOException {
        return cl.getResource(getClassFileName(clazzBinName));
    }
        
    /**
     * Returns the basename of the given fname w/o directory part
     */
    public static String getBasename(String fname) {
        fname = slashify(fname, false, false);
        int lios = fname.lastIndexOf('/');  // strip off dirname
        if(lios>=0) {
            fname = fname.substring(lios+1);
        }
        return fname;
    }
    
    /**
     * Returns unified '/' dirname including the last '/'
     */
    public static String getDirname(String fname) {
        fname = slashify(fname, false, false);
        int lios = fname.lastIndexOf('/');  // strip off dirname
        if(lios>=0) {
            fname = fname.substring(0, lios+1);
        }
        return fname;
    }
    
    private static String toLowerCase(String arg) {
        if (arg == null) {
            return null;
        }

        return arg.toLowerCase();
    }
    
    /***
     * 
     * RESOURCE LOCATION STUFF
     *  
     */
    
    /**
     * Locating a resource using {@link #getResource(String, ClassLoader)}:
     * <ul>
     *   <li><i>relative</i>: <code>context</code>'s package name-path plus <code>resourcePath</code> via <code>context</code>'s ClassLoader. 
     *       This allows locations relative to JAR- and other URLs. 
     *       The <code>resourcePath</code> may start with <code>../</code> to navigate to parent folder.</li>
     *   <li><i>absolute</i>: <code>context</code>'s ClassLoader and the <code>resourcePath</code> as is (filesystem)</li>
     * </ul>
     *
     * <p>
     * Returns the resolved and open URLConnection or null if not found.
     * </p>
     * 
     * @see #getResource(String, ClassLoader)
     * @see ClassLoader#getResource(String)
     * @see ClassLoader#getSystemResource(String)
     */
    public static URLConnection getResource(Class<?> context, String resourcePath) {
        if(null == resourcePath) {
            return null;
        }        
        ClassLoader contextCL = (null!=context)?context.getClassLoader():IOUtil.class.getClassLoader();
        URLConnection conn = null;
        if(null != context) {
            // scoping the path within the class's package            
            final String className = context.getName().replace('.', '/');
            final int lastSlash = className.lastIndexOf('/');
            if (lastSlash >= 0) {
                conn = getResource(className.substring(0, lastSlash + 1) + resourcePath, contextCL);
            }
            if(DEBUG) {
                System.err.println("IOUtil: found <"+resourcePath+"> within class package: "+(null!=conn));
            }
        } else if(DEBUG) {
            System.err.println("IOUtil: null context");
        }
        if(null == conn) {
            conn = getResource(resourcePath, contextCL);
            if(DEBUG) {
                System.err.println("IOUtil: found <"+resourcePath+"> by classloader: "+(null!=conn));
            }
        }
        return conn;
    }

    /**
     * Locating a resource using the ClassLoader's facilities.
     * <p>
     * Returns the resolved and connected URLConnection or null if not found.
     * </p>
     *
     * @see ClassLoader#getResource(String)
     * @see ClassLoader#getSystemResource(String)
     * @see URL#URL(String)
     * @see File#File(String)
     */
    public static URLConnection getResource(String resourcePath, ClassLoader cl) {
        if(null == resourcePath) {
            return null;
        }
        if(DEBUG) {
            System.err.println("IOUtil: locating <"+resourcePath+">, has cl: "+(null!=cl));
        }
        if(resourcePath.startsWith(AssetURLContext.asset_protocol_prefix)) {
            try {
                return AssetURLContext.createURL(resourcePath, cl).openConnection();
            } catch (IOException ioe) {
                if(DEBUG) {
                    System.err.println("IOUtil: Catched Exception:");
                    ioe.printStackTrace();
                }
                return null;
            }
        } else {
            try {
                return AssetURLContext.resolve(resourcePath, cl);
            } catch (IOException ioe) {
                if(DEBUG) {
                    System.err.println("IOUtil: Catched Exception:");
                    ioe.printStackTrace();
                }
            }
        }
        return null;
    }

    /**
     * Generates a path for the 'relativeFile' relative to the 'baseLocation'.
     * 
     * @param baseLocation denotes a directory
     * @param relativeFile denotes a relative file to the baseLocation
     */
    public static String getRelativeOf(File baseLocation, String relativeFile) {
        if(null == relativeFile) {
            return null;
        }
        
        if (baseLocation != null) {
            final File file = new File(baseLocation, relativeFile);
            // Handle things on Windows
            return slashify(file.getPath(), false, false);
        }
        return null;
    }

    /**
     * @param path assuming a slashified path beginning with "/" as it's root directory, either denotes a file or directory.
     * @return parent of path
     * @throws MalformedURLException if path is empty or has parent no directory available 
     */
    public static String getParentOf(String path) throws MalformedURLException {
        final int pl = null!=path ? path.length() : 0;
        if(pl == 0) {
            throw new MalformedURLException("path is empty <"+path+">");
        }
        
        final int e = path.lastIndexOf("/");
        if( e < 0 ) {
            throw new MalformedURLException("path contains no '/' <"+path+">");
        }
        if( e == 0 ) {
            // path is root directory
            throw new MalformedURLException("path has no parents <"+path+">");
        }
        if( e <  pl - 1 ) {
            // path is file, return it's parent directory
            return path.substring(0, e+1);
        }
        final int j = path.lastIndexOf("!") + 1; // '!' Separates JARFile entry -> local start of path 
        // path is a directory ..
        final int p = path.lastIndexOf("/", e-1);
        if( p >= j) {
            return path.substring(0, p+1);
        }
        throw new MalformedURLException("parent of path contains no '/' <"+path+">");
    }
    
    /**
     * @param path assuming a slashified path beginning with "/" as it's root directory, either denotes a file or directory.
     * @return clean path string where <code>../</code> and <code>./</code> is resolved. 
     * @throws MalformedURLException if path is empty or has no parent directory available while resolving <code>../</code>
     */
    public static String cleanPathString(String path) throws MalformedURLException {
        int idx;
        while ( ( idx = path.indexOf("../") ) >= 0 ) {
            path = getParentOf(path.substring(0, idx)) + path.substring(idx+3);
        }
        while ( ( idx = path.indexOf("./") ) >= 0 ) {
            path = path.substring(0, idx) + path.substring(idx+2);
        }
        return path;
    }
    
    /**
     * Generates a path for the 'relativeFile' relative to the 'baseLocation',
     * hence the result is a absolute location.
     * 
     * @param baseLocation denotes a URL to a directory if ending w/ '/', otherwise we assume a file
     * @param relativeFile denotes a relative file to the baseLocation's parent directory
     * @throws MalformedURLException 
     */
    public static URL getRelativeOf(URL baseLocation, String relativeFile) throws MalformedURLException {    
        final String scheme = baseLocation.getProtocol();
        final String auth = baseLocation.getAuthority();
        String path = baseLocation.getPath();
        String query = baseLocation.getQuery();
        String fragment = baseLocation.getRef();
        
        if(!path.endsWith("/")) {
            path = getParentOf(path);
        }
        return compose(scheme, auth, path, relativeFile, query, fragment);
    }
    
    public static URL compose(String scheme, String auth, String path1, String path2, String query, String fragment) throws MalformedURLException {
        StringBuilder sb = new StringBuilder();
        if(null!=scheme) {
            sb.append(scheme);
            sb.append(":");
        }
        if(null!=auth) {
            sb.append("//");
            sb.append(auth);
        }
        if(null!=path1) {
            sb.append(path1);
        }
        if(null!=path2) {
            sb.append(path2);
        }
        if(null!=query) {
            sb.append("?");
            sb.append(query);
        }
        if(null!=fragment) {
            sb.append("#");
            sb.append(fragment);
        }
        return new URL(cleanPathString(sb.toString()));
    }    
    
    /**
     * Returns the connected URLConnection, or null if not url is not available
     */
    public static URLConnection openURL(URL url) {
        return openURL(url, ".");
    }
    
    /**
     * Returns the connected URLConnection, or null if not url is not available
     */
    public static URLConnection openURL(URL url, String dbgmsg) {
        if(null!=url) {
            try {
                final URLConnection c = url.openConnection();
                c.connect(); // redundant
                if(DEBUG) {
                    System.err.println("IOUtil: urlExists("+url+") ["+dbgmsg+"] - true");
                }
                return c;
            } catch (IOException ioe) { 
                if(DEBUG) {
                    System.err.println("IOUtil: urlExists("+url+") ["+dbgmsg+"] - false - "+ioe.getClass().getSimpleName()+": "+ioe.getMessage());
                    ioe.printStackTrace();
                }                
            }
        } else if(DEBUG) {
            System.err.println("IOUtil: no url - urlExists(null) ["+dbgmsg+"]");
        }                
        
        return null;
    }
    
    /**
     * Utilizing {@link File#createTempFile(String, String, File)} using
     * {@link #getTempRoot(AccessControlContext)} as the directory parameter, ie. location 
     * of the root temp folder.
     * 
     * @see File#createTempFile(String, String)
     * @see File#createTempFile(String, String, File)
     * @see #getTempRoot(AccessControlContext)
     * 
     * @param prefix
     * @param suffix
     * @return
     * @throws IllegalArgumentException
     * @throws IOException
     * @throws SecurityException
     */
    public static File createTempFile(String prefix, String suffix, AccessControlContext acc) 
        throws IllegalArgumentException, IOException, SecurityException 
    {        
        return File.createTempFile( prefix, suffix, getTempRoot(acc) );
    }
    
    /**
     * Returns a platform independent writable directory for temporary files. 
     * <p>
     * On standard Java, the folder specified by <code>java.io.tempdir</code>
     * is returned.
     * </p> 
     * <p>
     * On Android a <code>temp</code> folder relative to the applications local folder 
     * (see {@link Context#getDir(String, int)}) is returned, if
     * the Android application/activity has registered it's Application Context
     * via {@link jogamp.common.os.android.StaticContext.StaticContext#init(Context, ClassLoader) StaticContext.init(..)}.
     * This allows using the temp folder w/o the need for <code>sdcard</code>
     * access, which would be the <code>java.io.tempdir</code> location on Android!
     * </p>
     * @param acc The security {@link AccessControlContext} to access <code>java.io.tmpdir</code> 
     * 
     * @throws SecurityException if access to <code>java.io.tmpdir</code> is not allowed within the current security context
     * @throws RuntimeException is the property <code>java.io.tmpdir</code> or the resulting temp directory is invalid
     *  
     * @see PropertyAccess#getProperty(String, boolean, java.security.AccessControlContext)
     * @see Context#getDir(String, int)
     */
    public static File getTempRoot(AccessControlContext acc)
        throws SecurityException, RuntimeException
    {
        {
            final File tmpRoot = AndroidUtils.getTempRoot(acc); // null if ( !Android || no android-ctx )
            if(null != tmpRoot) {
                return tmpRoot;
            }
        }
        final String tmpRootName = PropertyAccess.getProperty(java_io_tmpdir_propkey, false, acc);
        if(null == tmpRootName || 0 == tmpRootName.length()) {
            throw new RuntimeException("Property '"+java_io_tmpdir_propkey+"' value is empty: <"+tmpRootName+">");
        }
        final File tmpRoot = new File(tmpRootName);
        if(null==tmpRoot || !tmpRoot.isDirectory() || !tmpRoot.canWrite()) {
            throw new RuntimeException("Not a writable directory: '"+tmpRoot+"', retrieved by propery '"+java_io_tmpdir_propkey+"'");
        }
        if(DEBUG) {
            System.err.println("IOUtil.getTempRoot(): temp dir: "+tmpRoot.getAbsolutePath());
        }
        return tmpRoot;
    }
    
    /**
     * This methods finds [and creates] a temporary directory:
     * <pre>
     *    for(tempBaseDir = tempRootDir + tmpDirPrefix + _ + [000000-999999]) {
     *      if(tempBaseDir.isDirectory()) {
     *          if(tempBaseDir.canWrite()) {
     *              return tempBaseDir;
     *          }
     *      } else {
     *          tempBaseDir.mkdir();
     *          return tempBaseDir;
     *      }
     *    }
     * </pre>
     * The <code>tempRootDir</code> is retrieved by {@link #getTempRoot(AccessControlContext)}.
     * <p>
     * The iteration through [000000-999999] ensures that the code is multi-user save.
     * </p>
     * @param tmpDirPrefix
     * @return a temporary directory, writable by this user
     * @throws IOException
     * @throws SecurityException
     */
    public static File getTempDir(String tmpDirPrefix, AccessControlContext acc)
        throws IOException, SecurityException
    {
       final File tempRoot = IOUtil.getTempRoot(acc);
       
       for(int i = 0; i<=999999; i++) {
           final String tmpDirSuffix = String.format("_%06d", i); // 6 digits for iteration
           final File tmpBaseDir = new File(tempRoot, tmpDirPrefix+tmpDirSuffix);
           if (tmpBaseDir.isDirectory()) {
               // existing directory
               if(tmpBaseDir.canWrite()) {
                   // can write - OK
                   return tmpBaseDir; 
               }
               // not writable, hence used by another user - continue
           } else {
               // non existing directory, create and validate it
               tmpBaseDir.mkdir();
               if (!tmpBaseDir.isDirectory()) {
                   throw new IOException("Cannot create temp base directory " + tmpBaseDir);
               }
               if(!tmpBaseDir.canWrite()) {
                   throw new IOException("Cannot write to created temp base directory " + tmpBaseDir);
               }
               return tmpBaseDir; // created and writable - OK
           }
       }
       throw new IOException("Could not create temp directory @ "+tempRoot.getAbsolutePath()+tmpDirPrefix+"_*");        
    }
    
    public static void close(Closeable stream, boolean throwRuntimeException) throws RuntimeException {
        if(null != stream) {
            try {
                stream.close();
            } catch (IOException e) {
                if(throwRuntimeException) {
                    throw new RuntimeException(e);
                } else if(DEBUG) {
                    System.err.println("Catched Exception: ");
                    e.printStackTrace();
                }
            }
        }        
    }
}