Java Reference
In-Depth Information
public class BufferStateTrace {
public static void main(String[] args) {
String phrase = "Garbage in, garbage out.\n";
Path file = Paths.get(System.getProperty("user.home")).
resolve("Beginning Java
Stuff").resolve("charData.txt");
try {
// Make sure we have the directory
Files.createDirectories(file.getParent());
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
System.out.println("New file is: " + file);
try (WritableByteChannel channel = Files.newByteChannel(file,
EnumSet.of(WRITE,
CREATE))) {
ByteBuffer buf = ByteBuffer.allocate(1024);
System.out.printf(
"\nNew buffer:
position = %1*2d
Limit = %2*4d
capacity
= %3*4d",
buf.position(), buf.limit(),
buf.capacity());
// Load the data into the buffer
for(char ch : phrase.toCharArray())
buf.putChar(ch);
System.out.printf(
"\nBuffer after loading: position = %1*2d
Limit = %2*4d
capacity
= %3*4d",
buf.position(), buf.limit(),
buf.capacity());
buf.flip();
// Flip the buffer ready for file
write
System.out.printf(
"\nBuffer after flip:
position = %1*2d
Limit = %2*4d
capacity
= %3*4d",
buf.position(), buf.limit(),
buf.capacity());
channel.write(buf);
// Write the buffer to the file
channel
buf.flip();
channel.write(buf);
// Write the buffer again to the
file channel
System.out.println("\nBuffer contents written to the file -
twice.");
} catch (IOException e) {
e.printStackTrace();
}
}
}
