Java™ Platform
Standard Ed. 6

java.util.logging
Class StreamHandler

java.lang.Object
  extended by java.util.logging.Handler
      extended by java.util.logging.StreamHandler
Direct Known Subclasses:
ConsoleHandler, FileHandler, SocketHandler

public class StreamHandler
extends Handler

Stream based logging Handler.

This is primarily intended as a base class or support class to be used in implementing other logging Handlers.

LogRecords are published to a given java.io.OutputStream.

Configuration: By default each StreamHandler is initialized using the following LogManager configuration properties. If properties are not defined (or have invalid values) then the specified default values are used.

Since:
1.4

Constructor Summary
StreamHandler()
          Create a StreamHandler, with no current output stream.
StreamHandler(OutputStream out, Formatter formatter)
          Create a StreamHandler with a given Formatter and output stream.
 
Method Summary
 void close()
          Close the current output stream.
 void flush()
          Flush any buffered messages.
 boolean isLoggable(LogRecord record)
          Check if this Handler would actually log a given LogRecord.
 void publish(LogRecord record)
          Format and publish a LogRecord.
 void setEncoding(String encoding)
          Set (or change) the character encoding used by this Handler.
protected  void setOutputStream(OutputStream out)
          Change the output stream.
 
Methods inherited from class java.util.logging.Handler
getEncoding, getErrorManager, getFilter, getFormatter, getLevel, reportError, setErrorManager, setFilter, setFormatter, setLevel
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

StreamHandler

public StreamHandler()
Create a StreamHandler, with no current output stream.


StreamHandler

public StreamHandler(OutputStream out,
                     Formatter formatter)
Create a StreamHandler with a given Formatter and output stream.

Parameters:
out - the target output stream
formatter - Formatter to be used to format output
Method Detail

setOutputStream

protected void setOutputStream(OutputStream out)
                        throws SecurityException
Change the output stream.

If there is a current output stream then the Formatter's tail string is written and the stream is flushed and closed. Then the output stream is replaced with the new output stream.

Parameters:
out - New output stream. May not be null.
Throws:
SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").

setEncoding

public void setEncoding(String encoding)
                 throws SecurityException,
                        UnsupportedEncodingException
Set (or change) the character encoding used by this Handler.

The encoding should be set before any LogRecords are written to the Handler.

Overrides:
setEncoding in class Handler
Parameters:
encoding - The name of a supported character encoding. May be null, to indicate the default platform encoding.
Throws:
SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
UnsupportedEncodingException - if the named encoding is not supported.

publish

public void publish(LogRecord record)
Format and publish a LogRecord.

The StreamHandler first checks if there is an OutputStream and if the given LogRecord has at least the required log level. If not it silently returns. If so, it calls any associated Filter to check if the record should be published. If so, it calls its Formatter to format the record and then writes the result to the current output stream.

If this is the first LogRecord to be written to a given OutputStream, the Formatter's "head" string is written to the stream before the LogRecord is written.

Specified by:
publish in class Handler
Parameters:
record - description of the log event. A null record is silently ignored and is not published

isLoggable

public boolean isLoggable(LogRecord record)
Check if this Handler would actually log a given LogRecord.

This method checks if the LogRecord has an appropriate level and whether it satisfies any Filter. It will also return false if no output stream has been assigned yet or the LogRecord is Null.

Overrides:
isLoggable in class Handler
Parameters:
record - a LogRecord
Returns:
true if the LogRecord would be logged.

flush

public void flush()
Flush any buffered messages.

Specified by:
flush in class Handler

close

public void close()
           throws SecurityException
Close the current output stream.

The Formatter's "tail" string is written to the stream before it is closed. In addition, if the Formatter's "head" string has not yet been written to the stream, it will be written before the "tail" string.

Specified by:
close in class Handler
Throws:
SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").

Java™ Platform
Standard Ed. 6

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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