Skip to content

Most visited

Recently visited

navigation

Handler

public abstract class Handler
extends Object

java.lang.Object
   ↳ java.util.logging.Handler
Known Direct Subclasses
Known Indirect Subclasses


A Handler object takes log messages from a Logger and exports them. It might for example, write them to a console or write them to a file, or send them to a network logging service, or forward them to an OS log, or whatever.

A Handler can be disabled by doing a setLevel(Level.OFF) and can be re-enabled by doing a setLevel with an appropriate level.

Handler classes typically use LogManager properties to set default values for the Handler's Filter, Formatter, and Level. See the specific documentation for each concrete Handler class.

Summary

Protected constructors

Handler()

Default constructor.

Public 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 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.

Protected methods

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

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

Inherited methods

From class java.lang.Object

Protected constructors

Handler

Added in API level 1
Handler ()

Default constructor. The resulting Handler has a log level of Level.ALL, no Formatter, and no Filter. A default ErrorManager instance is installed as the ErrorManager.

Public methods

close

Added in API level 1
void close ()

Close the Handler and free all associated resources.

The close method will perform a flush and then close the Handler. After close has been called this Handler should no longer be used. Method calls may either be silently ignored or may throw runtime exceptions.

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

flush

Added in API level 1
void flush ()

Flush any buffered output.

getEncoding

Added in API level 1
String getEncoding ()

Return the character encoding for this Handler.

Returns
String The encoding name. May be null, which indicates the default encoding should be used.

getErrorManager

Added in API level 1
ErrorManager getErrorManager ()

Retrieves the ErrorManager for this Handler.

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

getFilter

Added in API level 1
Filter getFilter ()

Get the current Filter for this Handler.

Returns
Filter a Filter object (may be null)

getFormatter

Added in API level 1
Formatter getFormatter ()

Return the Formatter for this Handler.

Returns
Formatter the Formatter (may be null).

getLevel

Added in API level 1
Level getLevel ()

Get the log level specifying which messages will be logged by this Handler. Message levels lower than this level will be discarded.

Returns
Level the level of messages being logged.

isLoggable

Added in API level 1
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 also may make other Handler specific checks that might prevent a handler from logging the LogRecord. It will return false if the LogRecord is null.

Parameters
record LogRecord: a LogRecord
Returns
boolean true if the LogRecord would be logged.

publish

Added in API level 1
void publish (LogRecord record)

Publish a LogRecord.

The logging request was made initially to a Logger object, which initialized the LogRecord and forwarded it here.

The Handler is responsible for formatting the message, when and if necessary. The formatting should include localization.

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

setEncoding

Added in API level 1
void setEncoding (String encoding)

Set 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.

setErrorManager

Added in API level 1
void setErrorManager (ErrorManager em)

Define an ErrorManager for this Handler.

The ErrorManager's "error" method will be invoked if any errors occur while using this Handler.

Parameters
em ErrorManager: the new ErrorManager
Throws
SecurityException if a security manager exists and if the caller does not have LoggingPermission("control").

setFilter

Added in API level 1
void setFilter (Filter newFilter)

Set a Filter to control output on this Handler.

For each call of publish the Handler will call this Filter (if it is non-null) to check if the LogRecord should be published or discarded.

Parameters
newFilter Filter: a Filter object (may be null)
Throws
SecurityException if a security manager exists and if the caller does not have LoggingPermission("control").

setFormatter

Added in API level 1
void setFormatter (Formatter newFormatter)

Set a Formatter. This Formatter will be used to format LogRecords for this Handler.

Some Handlers may not use Formatters, in which case the Formatter will be remembered, but not used.

Parameters
newFormatter Formatter: the Formatter to use (may not be null)
Throws
SecurityException if a security manager exists and if the caller does not have LoggingPermission("control").

setLevel

Added in API level 1
void setLevel (Level newLevel)

Set the log level specifying which message levels will be logged by this Handler. Message levels lower than this value will be discarded.

The intention is to allow developers to turn on voluminous logging, but to limit the messages that are sent to certain Handlers.

Parameters
newLevel Level: the new value for the log level
Throws
SecurityException if a security manager exists and if the caller does not have LoggingPermission("control").

Protected methods

reportError

Added in API level 1
void reportError (String msg, 
                Exception ex, 
                int code)

Protected convenience method to report an error to this Handler's ErrorManager. Note that this method retrieves and uses the ErrorManager without doing a security check. It can therefore be used in environments where the caller may be non-privileged.

Parameters
msg String: a descriptive string (may be null)
ex Exception: an exception (may be null)
code int: an error code defined in ErrorManager
This site uses cookies to store your preferences for site-specific language and display options.

Hooray!

This class requires API level or higher

This doc is hidden because your selected API level for the documentation is . You can change the documentation API level with the selector above the left navigation.

For more information about specifying the API level your app requires, read Supporting Different Platform Versions.