public void testWindows() throws Exception {
// ==== Testing Windows filesystem ===
// two options to write - WRITE, WRITE + APPEND. Simple writes just rewrite current values
SeekableByteChannel s =
Files.newByteChannel(
Paths.get("test.txt"),
StandardOpenOption.WRITE,
StandardOpenOption.READ,
StandardOpenOption.CREATE); // , StandardOpenOption.APPEND);
ByteBuffer bb = ByteBuffer.wrap("12345".getBytes());
s.truncate(0); // clear file
s.position(0); // start position
s.write(bb);
bb.position(2);
s.write(bb);
//
s.position(0);
byte[] bbrb = new byte[(int) s.size()];
s.read(ByteBuffer.wrap(bbrb));
System.out.println(new String(bbrb)); // should be 12345345
s.close();
}
private static void testReopenAndSeek() throws IOException {
long position = 0;
long start = System.currentTimeMillis();
while (true) {
try (SeekableByteChannel c = Files.newByteChannel(testFile, READ)) {
b.clear();
c.position(position);
int nbytes = c.read(b);
if (nbytes <= 0) break;
position += nbytes;
}
}
long end = System.currentTimeMillis();
logger.info("testReopenAndSeek {} ms", end - start);
}
public void checkRanges() throws IOException {
if (currentRange != null) {
if (counter >= currentRange[1]) {
counter = -1;
}
}
if (counter == -1) {
if (!ranges.isEmpty()) {
currentRange = ranges.remove(0);
// reset channel
channel.position(currentRange[0]);
counter = 0;
} else {
currentRange = null;
}
}
}
// this method read every char at every 10 length position.
private void executeRead() throws IOException {
System.out.println("executeRead started");
try (SeekableByteChannel channel =
Files.newByteChannel(
Paths.get("c:/temp/channelExample.txt"), EnumSet.of(StandardOpenOption.READ))) {
ByteBuffer buffer = ByteBuffer.allocate(1);
long position = 0;
while (true) {
buffer.clear();
channel.position(position);
if (channel.read(buffer) < 0) break;
buffer.flip();
System.out.println(
"position : "
+ position
+ ", char : "
+ Charset.defaultCharset().decode(buffer)); // print chars from every 10 positions.
position += 10;
}
}
}
private static SeekableByteChannel addHeader(SeekableByteChannel input) {
try {
int total = (int) input.size();
final String comment =
"@HD\tVN:1.0 SO:unsorted\n"
+ "@SQ\tSN:chr1\tLN:101\n"
+ "@SQ\tSN:chr2\tLN:101\n"
+ "@SQ\tSN:chr3\tLN:101\n"
+ "@RG\tID:0\tSM:JP was here\n";
byte[] commentBuf = comment.getBytes();
ByteBuffer buf = ByteBuffer.allocate(total + commentBuf.length);
buf.put(commentBuf);
input.position(0);
while (input.read(buf) > 0) {
// read until EOF
}
buf.flip();
return new SeekableByteChannelFromBuffer(buf);
} catch (IOException x) {
throw new RuntimeException(x);
}
}