Handler (Java Platform SE 8 )

java.lang.Object
- java.util.logging.Handler

Direct Known Subclasses:

MemoryHandler, StreamHandler
```
public abstract class Handler
extends Object
```
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.

Since:

1.4

Constructor Summary

Constructors
Modifier Constructor and Description

protected Handler()
Default constructor.

Constructors
Modifier	Constructor and Description
`protected`	`Handler()` Default constructor.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`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`.
`protected 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`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Handler
```
protected 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.
- Method Detail
  - publish
```
public abstract 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 - description of the log event. A null record is silently ignored and is not published
  - flush
```
public abstract void flush()
```
    Flush any buffered output.
  - close
```
public abstract void close()
                    throws SecurityException
```
    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").
  - setFormatter
```
public void setFormatter(Formatter newFormatter)
                  throws SecurityException
```
    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 - the Formatter to use (may not be null)
    
    Throws:
    
    SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
  - getFormatter
```
public Formatter getFormatter()
```
    Return the Formatter for this Handler.
    
    Returns:
    
    the Formatter (may be null).
  - setEncoding
```
public void setEncoding(String encoding)
                 throws SecurityException,
                        UnsupportedEncodingException
```
    Set the character encoding used by this Handler.
    The encoding should be set before any LogRecords are written to the 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.
  - getEncoding
```
public String getEncoding()
```
    Return the character encoding for this Handler.
    
    Returns:
    
    The encoding name. May be null, which indicates the default encoding should be used.
  - setFilter
```
public void setFilter(Filter newFilter)
               throws SecurityException
```
    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 - a Filter object (may be null)
    
    Throws:
    
    SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
  - getFilter
```
public Filter getFilter()
```
    Get the current Filter for this Handler.
    
    Returns:
    
    a Filter object (may be null)
  - setErrorManager
```
public 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 - the new ErrorManager
    
    Throws:
    
    SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
  - getErrorManager
```
public ErrorManager getErrorManager()
```
    Retrieves the ErrorManager for this Handler.
    
    Returns:
    
    the ErrorManager for this Handler
    
    Throws:
    
    SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
  - reportError
```
protected 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 - a descriptive string (may be null)
    
    ex - an exception (may be null)
    
    code - an error code defined in ErrorManager
  - setLevel
```
public void setLevel(Level newLevel)
              throws SecurityException
```
    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 - the new value for the log level
    
    Throws:
    
    SecurityException - if a security manager exists and if the caller does not have LoggingPermission("control").
  - getLevel
```
public 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:
    
    the level of messages being logged.
  - 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 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 - a LogRecord
    
    Returns:
    
    true if the LogRecord would be logged.

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Class Handler

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Handler

Method Detail

publish

flush

close

setFormatter

getFormatter

setEncoding

getEncoding

setFilter

getFilter

setErrorManager

getErrorManager

reportError

setLevel

getLevel

isLoggable