StreamHandler

public class StreamHandler
extends Handler

java.lang.Object
   ↳ java.util.logging.Handler
     ↳ java.util.logging.StreamHandler
ConsoleHandler This Handler publishes log records to System.err
FileHandler Simple file logging Handler
SocketHandler Simple network logging 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 where <handler-name> refers to the fully-qualified class name of the handler. If properties are not defined (or have invalid values) then the specified default values are used.

  • <handler-name>.level specifies the default level for the Handler (defaults to Level.INFO).
  • <handler-name>.filter specifies the name of a Filter class to use (defaults to no Filter).
  • <handler-name>.formatter specifies the name of a Formatter class to use (defaults to java.util.logging.SimpleFormatter).
  • <handler-name>.encoding the name of the character set encoding to use (defaults to the default platform encoding).

For example, the properties for StreamHandler would be:

  • java.util.logging.StreamHandler.level=INFO
  • java.util.logging.StreamHandler.formatter=java.util.logging.SimpleFormatter

For a custom handler, e.g. com.foo.MyHandler, the properties would be:

  • com.foo.MyHandler.level=INFO
  • com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter

Summary

Public constructors

StreamHandler()

Create a StreamHandler, with no current output stream.

StreamHandler(OutputStream out, Formatter formatter)

Create a StreamHandler with a given Formatter and output stream.

Public methods

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 methods

void setOutputStream(OutputStream out)

Change the output stream.

Inherited methods

abstract void close()

Close the Handler and free all associated resources.

abstract void flush()

Flush any buffered output.

String getEncoding()

Return the character encoding for this Handler.

ErrorManager getErrorManager()

Retrieves the ErrorManager for this Handler.

Filter getFilter()

Get the current Filter for this Handler.

Formatter getFormatter()

Return the Formatter for this Handler.

Level getLevel()

Get the log level specifying which messages will be logged by this Handler.

boolean isLoggable(LogRecord record)

Check if this Handler would actually log a given LogRecord.

abstract void publish(LogRecord record)

Publish a LogRecord.

void reportError(String msg, Exception ex, int code)

Protected convenience method to report an error to this Handler's ErrorManager.

void setEncoding(String encoding)

Set the character encoding used by this Handler.

void setErrorManager(ErrorManager em)

Define an ErrorManager for this Handler.

void setFilter(Filter newFilter)

Set a Filter to control output on this Handler.

void setFormatter(Formatter newFormatter)

Set a Formatter.

void setLevel(Level newLevel)

Set the log level specifying which message levels will be logged by this Handler.

Object clone()

Creates and returns a copy of this object.

boolean equals(Object obj)

Indicates whether some other object is "equal to" this one.

void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

final Class<?> getClass()

Returns the runtime class of this Object.

int hashCode()

Returns a hash code value for the object.

final void notify()

Wakes up a single thread that is waiting on this object's monitor.

final void notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String toString()

Returns a string representation of the object.

final void wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

StreamHandler

Added in API level 1
public StreamHandler ()

Create a StreamHandler, with no current output stream.

StreamHandler

Added in API level 1
public StreamHandler (OutputStream out, 
                Formatter formatter)

Create a StreamHandler with a given Formatter and output stream.

Parameters
out OutputStream: the target output stream

formatter Formatter: Formatter to be used to format output

Public methods

close

Added in API level 1
public void close ()

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.

Throws
SecurityException if a security manager exists and if the caller does not have LoggingPermission("control").

flush

Added in API level 1
public void flush ()

Flush any buffered messages.

isLoggable

Added in API level 1
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.

Parameters
record LogRecord: a LogRecord

Returns
boolean true if the LogRecord would be logged.

publish

Added in API level 1
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.

Parameters
record LogRecord: description of the log event. A null record is silently ignored and is not published

setEncoding

Added in API level 1
public void setEncoding (String encoding)

Set (or change) the character encoding used by this Handler.

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

Parameters
encoding String: 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.

Protected methods

setOutputStream

Added in API level 1
protected void setOutputStream (OutputStream out)

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 OutputStream: New output stream. May not be null.

Throws
SecurityException if a security manager exists and if the caller does not have LoggingPermission("control").