현재 까지 나온 Java 6.0 까지의 I/O 성능향상을 위한 Sun의 작업내역을 보실수가 있네요.. ^^
제가 보기에 Java 6의 가장 큰 이슈는 SelectorProvider가 Linux epoll 기법(IOCP와 비슷)을 지원한다는 것입니다.. 대충 찾아보니.. 여러개의 버그가 리포팅이 되어 있긴 하지만, 추후 대용량 처리를 위해서는 좋은 모습인거 같습니다. ^^
출처는 http://java.sun.com/javase/6/docs/technotes/guides/io/enhancements.html 입니다…..
One new class is provided:
Console– Contains methods to access a character-based console device. The
readPassword()methods disable echoing thus they are suitable for retrieval of sensitive data such as passwords. The method
System.console()returns the unique console associated with the Java Virtual Machine.
The following new methods were added to
- Methods to retrieve disk usage information:
getTotalSpace()returns the size of the partition in bytes
getFreeSpace()returns the number of unallocated bytes in the partition
getUsableSpace()returns the number of bytes available on the partition and includes checks for write permissions and other operating system restrictions
- Methods to set or query file permissions:
setWritable(boolean writable, boolean ownerOnly)and
setWritable(boolean writable)set the owner’s or everybody’s write permission
setReadable(boolean readable, boolean ownerOnly)and
setReadable(boolean readable)set the owner’s or everybody’s read permission
setExecutable(boolean executable, boolean ownerOnly)and
setExecutable(boolean executable)set the owner’s or everybody’s execute permission
canExecute()tests the value of the execute permission
Constructors were added to the following class:
IOExceptionsupports exception chaining via the addition of the new constructors
The behavior of the following method was modified:
File.isFile()Windows implementation has been modified to always return
falsefor reserved device names such as CON, NUL, AUX, LPT, etc. Previously it returned
true, which customers considered a bug because it was inconsistent with behavior for devices on Unix.
- A new
java.nio.channels.SelectorProviderimplementation that is based on the Linux epoll event notification facility is included. The epoll facility is available in the Linux 2.6, and newer, kernels. The new epoll-based
SelectorProviderimplementation is more scalable than the traditional poll-based
SelectorProviderimplementation when there are thousands of
SelectableChannels registered with a
Selector. The new
SelectorProviderimplementation will be used by default when the 2.6 kernel is detected. The poll-based
SelectorProviderwill be used when a pre-2.6 kernel is detected.
- The system property
java.nio.channels.FileChannel.lock()checks whether regions are locked by other instances of
FileChannel. Unless this system property is set to
FileChannel.lock()will throw an
OverlappingFileLockExceptionif an application attempts to lock a region that overlaps one that is locked by another instance of
FileChannel. The system property exists to provide compatibility with previous releases which do not implement the JVM-wide overlapping file lock check.
javax.net.ssl.SSLEnginewas added. The existing J2SDK 1.4.0 secure communication infrastructure,
javax.net.ssl.SSLSocket, was based on the I/O model of java.net.Socket. The
SSLEngineclass abstracts away the I/O model, and leaves developers free to secure communication pathways using alternate types of I/O.
SSLEnginecan be combined with the New I/O APIs to create implementations such as secure blocking or non-blocking
SocketChannels. For details see the JSSE Reference Guide.
- In the
getChannelmethods have been added to return the underlying
FileChannelobject, and the
closemethods have been revised to close the underlying channel.
- Similarly, in the
getChannelmethod has been added and the
closemethod has been revised to close the underlying channel. The
RandomAccessFileconstructors now support the mode characters “s” and “d” to allow the specification, at file-open time, of synchronous writes or synchronous-data writes.
- In the
OutputStreamWriterclasses, constructors have been added that take a stream and a
Charsetobject, and the
getEncodingmethods have been revised to return the historical name of the encoding being used. Constructors to
OutputStreamWriterhave been added that take existing
- The nio packages were added to supplement the I/O facilities provided the java.io package.
- Three new functions were added to the Java Native Interface (JNI) to support direct buffers. For information, see JNI Enhancements in v 1.4.