## org.w3c.jigsaw.filters
Class LogFilter

    java.lang.Object
      |
      +--org.w3c.tools.resources.AttributeHolder
            |
            +--org.w3c.tools.resources.Resource
                  |
                  +--org.w3c.tools.resources.FramedResource
                        |
                        +--org.w3c.tools.resources.ResourceFrame
                              |
                              +--org.w3c.tools.resources.ResourceFilter
                                    |
                                    +--org.w3c.jigsaw.filters.LogFilter

public class LogFilter
extends ResourceFilter

This filter provides a very flexible logger. It is not designed as a logger, in order to be plugable only on a sub-tree of the URL space (a logger would log all site accesses). It provides as much details as you want, and uses a very simple format: each log entry (or record is made of several lines having the folowing format:

    variable=value

A record starts with the special `url` variable value which provides the requested URL. The for each header that is to be logged, a variable is added in the record, prefixed by its scope. The scope can be either:

request
  to specify a request header,
reply
  to specify a reply header,
server
  to specify global server samples.

As an example, if you configure that filter to log the request's referer and the reply content length, a sample record will look like:

     url=http://www.w3.org/pub/WWW/Jigsaw/
     request.referer=http://www.w3.org/pub/WWW
     reply.content-length=10

Field Summary
`protected static int` `ATTR_LOGFILE` Attribute index - The log file to use to emit log record.
`protected static int` `ATTR_REPLY_HEADERS` Attribute index - The HTTP reply headers to dump
`protected static int` `ATTR_REQUEST_HEADERS` Attribute index - The HTTP request headers to dump
`static java.lang.String` `DONT_LOG` Name of the state that when set on the request will prevent logging.
`protected java.io.RandomAccessFile` `log` Open log descriptor, to write to the log.
`protected HeaderDescription[]` `repheaders` Compiled index of the reply headers to dump.
`protected HeaderDescription[]` `reqheaders` Compiled index of the request headers to dump.

Fields inherited from class org.w3c.tools.resources.ResourceFrame
`filterClass, frameListener, resource`

Fields inherited from class org.w3c.tools.resources.FramedResource
`ATTR_OID, attrListener, debugEvent, event_disabled, framesRef, structListener`

Fields inherited from class org.w3c.tools.resources.Resource
`ATTR_CONTEXT, ATTR_HELP_URL, ATTR_IDENTIFIER, ATTR_LAST_MODIFIED, ATTR_PARENT, ATTR_RESOURCE_FRAMES, ATTR_STORE_ENTRY, ATTR_URL, co, id`

Fields inherited from class org.w3c.tools.resources.AttributeHolder
`attributes, values`

Constructor Summary
`LogFilter()`

Method Summary
`protected HeaderDescription[]` `compileHeaders(HttpMessage kind, java.lang.String[] headers)` Compile the given set of header names into header indexes.
`java.io.File` `getLogfile()` Get the log file.
`java.lang.String[]` `getReplyHeaders()` Get the list of reply headers to dump.
`java.lang.String[]` `getRequestHeaders()` Get the list of request headers to dump.
`void` `initialize(java.lang.Object[] values)` Initialize the filter.
`protected void` `log(Request request, Reply reply)` Log the given request/reply transaction.
`protected void` `openLog()` Open the log stream, and make it available through `log`.
`ReplyInterface` `outgoingFilter(RequestInterface req, ReplyInterface rep)` Log the request.
`void` `setValue(int idx, java.lang.Object value)` Traop setValue calls.
`protected void` `writelog(java.lang.String record)` Write the given string to the log file.

Methods inherited from class org.w3c.tools.resources.ResourceFilter
`exceptionFilter, getTargetResource, ingoingFilter, ingoingFilter, initialize, lookup, outgoingFilter, outputFilter, pickleValues`

Methods inherited from class org.w3c.tools.resources.ResourceFrame
`addFrameEventListener, attributeChanged, checkRequest, eventDisabled, fireFrameEvent, frameModified, getFilters, getFilters, getFrameReference, getResource, getResourceReference, getSpaceEntry, getURLPath, lookupFilters, lookupFrames, perform, postFrameEvent, processEvent, registerResource, removeFrameEventListener, unregisterResource, updateDefaultChildAttributes`

Methods inherited from class org.w3c.tools.resources.FramedResource

`addAttributeChangedListener, addStructureChangedListener, collectFramesReference, delete, disableEvent, displayEvent, enableEvent, fireAttributeChangeEvent, fireStructureChangedEvent, fireStructureChangedEvent, frameAdded, frameRemoved, getClone, getFrame, getFrame, getFrameReference, getFrameReference, getFramesReference, getOid, markModified, notifyUnload, performFrames, postAttributeChangeEvent, postEvent, postStructureChangedEvent, postStructureChangedEvent, registerFrame, registerFrameIfNone, removeAttributeChangedListener, removeStructureChangedListener, setSilentValue, setSilentValue, unregisterFrame`

Methods inherited from class org.w3c.tools.resources.Resource
`acceptUnload, checkMultipleLock, collectFrames, getContext, getFrame, getFrames, getHelpURL, getHelpURL, getIdentifier, getLastModified, getParent, getServer, getSpace, getStoreEntry, getValue, getValue, isInitialized, isUnloaded, setContext, setContext, setValue, unsafeGetContext, unsafeGetIdentifier, unsafeGetValue, updateAttributes`

Methods inherited from class org.w3c.tools.resources.AttributeHolder
`definesAttribute, definesAttribute, getAttributes, getBoolean, getChar, getClone, getClone, getDouble, getFloat, getInt, getLong, getString, getValue, lookupAttribute, print, setBoolean, setChar, setDouble, setFloat, setInt, setLong, setString, setValue, unsafeGetString`

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

Field Detail

### DONT_LOG

    public static final java.lang.String DONT_LOG

  Name of the state that when set on the request will prevent logging.

### ATTR_REQUEST_HEADERS

    protected static int ATTR_REQUEST_HEADERS

  Attribute index - The HTTP request headers to dump

### ATTR_REPLY_HEADERS

    protected static int ATTR_REPLY_HEADERS

  Attribute index - The HTTP reply headers to dump

### ATTR_LOGFILE

    protected static int ATTR_LOGFILE

  Attribute index - The log file to use to emit log record.

### reqheaders

    protected HeaderDescription[] reqheaders

  Compiled index of the request headers to dump.

### repheaders

    protected HeaderDescription[] repheaders

  Compiled index of the reply headers to dump.

### log

    protected java.io.RandomAccessFile log

  Open log descriptor, to write to the log.

Constructor Detail

### LogFilter

    public LogFilter()

Method Detail

### compileHeaders

    protected HeaderDescription[] compileHeaders(HttpMessage kind,
                                                 java.lang.String[] headers)

  Compile the given set of header names into header indexes.
  Parameters:
    `kind` - An instance of the class whose headers are to be dumped.
    `headers` - The name of headers to compile.
  Returns:
    An array of header description, which will allow fast fetch of header values.

### writelog

    protected void writelog(java.lang.String record)

  Write the given string to the log file.
  Parameters:
    `record` - The string to write.

### openLog

    protected void openLog()

  Open the log stream, and make it available through `log`. If opening the stream failed, an appropriate error message is emitted and `log` remains set to null. If a log stream was already opened, it is first closed.

### getLogfile

    public java.io.File getLogfile()

  Get the log file.
  Returns:
    A File instance, or null if not set.

### getRequestHeaders

    public java.lang.String[] getRequestHeaders()

  Get the list of request headers to dump.
  Returns:
    An array of String containing the name of headers to dump, or null if undefined.

### getReplyHeaders

    public java.lang.String[] getReplyHeaders()

  Get the list of reply headers to dump.
  Returns:
    An array of String containing the name of headers to dump, or null if undefined.

### setValue

    public void setValue(int idx,
                         java.lang.Object value)

  Traop setValue calls. We maintain a compiled version of both the `request-headers` and the `reply-headers` attributes, make sure they stay in sync even when modified.
  Overrides:
    setValue in class ResourceFrame
  Tags copied from class: ResourceFrame
  Parameters:
    `idx` - The index of the attribute to modify.
    `value` - The new attribute value.

### log

    protected void log(Request request,
                       Reply reply)

  Log the given request/reply transaction. Dump a record for the given transaction.
  Parameters:
    `request` - The request to log.
    `reply` - It's associated reply.

### outgoingFilter

    public ReplyInterface outgoingFilter(RequestInterface req,
                                         ReplyInterface rep)
                                  throws ProtocolException

  Log the request.
  Overrides:
    outgoingFilter in class ResourceFilter
  Parameters:
    `request` - The request that has been handled.
    `reply` - It's associated reply.
  Throws:
    ProtocolException - If processing should be interrupted, because an abnormal situation occured.

### initialize

    public void initialize(java.lang.Object[] values)

  Initialize the filter.
  Overrides:
    initialize in class FramedResource
  Tags copied from class: FramedResource
  Parameters:
    `values` - Default attribute values.