oracle.ide.log
Class LogPrintWriter

java.lang.Object
  java.io.Writer
      java.io.PrintWriter
          oracle.ide.log.LogPrintWriter

public class LogPrintWriter

extends java.io.PrintWriter

This class provides a PrintWriter interface to a LogPage.

Field Summary

Fields inherited from class java.io.PrintWriter

out

Fields inherited from class java.io.Writer

lock

Constructor Summary

LogPrintWriter(LogPage logPage)
Constructs a LogPrintWriter that is wired into the specified LogPage.

Method Summary

LogPage	getLogPage() Directly returns the underlying LogPage for this LogPrintWriter.
LogPage	getWrappedLogPage() The need for a wrapped LogPage instance arises from the fact that: A typical LogPage implementation uses a thread to forward messages to the UI components (to avoid deadlocks in the IDE caused by the automatic showing of the log window or changing log pages in the log window), and Each LogPrintWriter uses a thread to forward messages to the underlying LogPage.

Methods inherited from class java.io.PrintWriter

checkError, close, flush, print, print, print, print, print, print, print, print, print, println, println, println, println, println, println, println, println, println, println, setError, write, write, write, write, write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LogPrintWriter

public LogPrintWriter(LogPage logPage)

Constructs a LogPrintWriter that is wired into the specified LogPage.

If the PrintWriter.close() method is called, the thread that is forwarding messages to the LogPage will be terminated. This disconnects the LogPrintWriter from the LogPage.

Note that the close() method will be called automatically when the LogPrintWriter is garbage collected, so an explicit call to close() is not required.

If creation of a pipe to the specified LogPage fails for some reason, the LogPrintWriter will be configured to forward all messages to System.out instead.

Method Detail

getLogPage

public LogPage getLogPage()

Directly returns the underlying LogPage for this LogPrintWriter.

getWrappedLogPage

public LogPage getWrappedLogPage()

The need for a wrapped LogPage instance arises from the fact that:

1. A typical LogPage implementation uses a thread to forward messages to the UI components (to avoid deadlocks in the IDE caused by the automatic showing of the log window or changing log pages in the log window), and
2. Each LogPrintWriter uses a thread to forward messages to the underlying LogPage.

Because thread scheduling in the JVM is nondeterministic, the simultaneous use of a LogPage and a corresponding LogPrintWriter instance can lead to an undesirable reordering of messages. In order to preserve the temporal ordering of messages, all messages must be queued through the same LogPrintWriter instance. The wrapped instance of LogPage returned by this method is there configured to delegate logging to this LogPrintWriter instance.

The main disadvantage of using getWrappedLogPage() is that the returned LogPage cannot be downcast to a specific LogPage implementation to use special implementation-specific APIs.