org.apache.logging.log4j.core
Interface Layout<T extends Serializable>

Type Parameters:

T - The Serializable type returned by toSerializable(LogEvent)

All Known Implementing Classes:

AbstractLayout, AbstractStringLayout, HTMLLayout, PatternLayout, RFC5424Layout, SerializedLayout, SyslogLayout, XMLLayout

public interface Layout<T extends Serializable>

Lays out a LogEvent in different formats. The formats are:

• byte[]
• an implementer of Serializable, like byte[]
• String
• LogEvent

Troublesome:

There is still a need for a character-based layout for character based event sinks (databases, etc). Would introduce an EventEncoder, EventRenderer or something similar for the logging event to byte encoding. (RG) A layout can be configured with a Charset and then Strings can be converted to byte arrays. OTOH, it isn't possible to write byte arrays as character streams.

Method Summary

Map<String,String>	getContentFormat() Returns a description of the content format.
String	getContentType() Returns the content type output by this layout.
byte[]	getFooter() Returns the format for the layout format.
byte[]	getHeader() Returns the header for the layout format.
byte[]	toByteArray(LogEvent event) Formats the event suitable for display.
T	toSerializable(LogEvent event) Formats the event as an Object that can be serialized.

Method Detail

getFooter

byte[] getFooter()

Returns the format for the layout format.

Returns:

The footer.

Troublesome:

the concept of header and footer is not universal, should not be on the base interface. (RG) I agree with this.

getHeader

byte[] getHeader()

Returns the header for the layout format.

Returns:

The header.

Troublesome:

the concept of header and footer is not universal, should not be on the base interface. (RG) I agree with this.

toByteArray

byte[] toByteArray(LogEvent event)

Formats the event suitable for display.

Parameters:

event - The Logging Event.

Returns:

The formatted event.

Troublesome:

Likely better to write to a OutputStream instead of return a byte[]. (RG) That limits how the Appender can use the Layout. For example, it might concatenate information in front or behind the data and then write it all to the OutputStream in one call.

toSerializable

T toSerializable(LogEvent event)

Formats the event as an Object that can be serialized.

Parameters:

event - The Logging Event.

Returns:

The formatted event.

getContentType

String getContentType()

Returns the content type output by this layout. The base class returns "text/plain".

Returns:

the content type.

getContentFormat

Map<String,String> getContentFormat()

Returns a description of the content format.

Returns:

a Map of key/value pairs describing the Layout-specific content format, or an empty Map if no content format descriptors are specified.