#region Apache License
|
//
|
// Licensed to the Apache Software Foundation (ASF) under one or more
|
// contributor license agreements. See the NOTICE file distributed with
|
// this work for additional information regarding copyright ownership.
|
// The ASF licenses this file to you under the Apache License, Version 2.0
|
// (the "License"); you may not use this file except in compliance with
|
// the License. You may obtain a copy of the License at
|
//
|
// http://www.apache.org/licenses/LICENSE-2.0
|
//
|
// Unless required by applicable law or agreed to in writing, software
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
// See the License for the specific language governing permissions and
|
// limitations under the License.
|
//
|
#endregion
|
|
using System;
|
using log4net.Core;
|
|
namespace log4net.Filter
|
{
|
/// <summary>
|
/// Subclass this type to implement customized logging event filtering
|
/// </summary>
|
/// <remarks>
|
/// <para>
|
/// Users should extend this class to implement customized logging
|
/// event filtering. Note that <see cref="log4net.Repository.Hierarchy.Logger"/> and
|
/// <see cref="log4net.Appender.AppenderSkeleton"/>, the parent class of all standard
|
/// appenders, have built-in filtering rules. It is suggested that you
|
/// first use and understand the built-in rules before rushing to write
|
/// your own custom filters.
|
/// </para>
|
/// <para>
|
/// This abstract class assumes and also imposes that filters be
|
/// organized in a linear chain. The <see cref="Decide"/>
|
/// method of each filter is called sequentially, in the order of their
|
/// addition to the chain.
|
/// </para>
|
/// <para>
|
/// The <see cref="Decide"/> method must return one
|
/// of the integer constants <see cref="FilterDecision.Deny"/>,
|
/// <see cref="FilterDecision.Neutral"/> or <see cref="FilterDecision.Accept"/>.
|
/// </para>
|
/// <para>
|
/// If the value <see cref="FilterDecision.Deny"/> is returned, then the log event is dropped
|
/// immediately without consulting with the remaining filters.
|
/// </para>
|
/// <para>
|
/// If the value <see cref="FilterDecision.Neutral"/> is returned, then the next filter
|
/// in the chain is consulted. If there are no more filters in the
|
/// chain, then the log event is logged. Thus, in the presence of no
|
/// filters, the default behavior is to log all logging events.
|
/// </para>
|
/// <para>
|
/// If the value <see cref="FilterDecision.Accept"/> is returned, then the log
|
/// event is logged without consulting the remaining filters.
|
/// </para>
|
/// <para>
|
/// The philosophy of log4net filters is largely inspired from the
|
/// Linux ipchains.
|
/// </para>
|
/// </remarks>
|
/// <author>Nicko Cadell</author>
|
/// <author>Gert Driesen</author>
|
public abstract class FilterSkeleton : IFilter
|
{
|
#region Member Variables
|
|
/// <summary>
|
/// Points to the next filter in the filter chain.
|
/// </summary>
|
/// <remarks>
|
/// <para>
|
/// See <see cref="Next"/> for more information.
|
/// </para>
|
/// </remarks>
|
private IFilter m_next;
|
|
#endregion
|
|
#region Implementation of IOptionHandler
|
|
/// <summary>
|
/// Initialize the filter with the options set
|
/// </summary>
|
/// <remarks>
|
/// <para>
|
/// This is part of the <see cref="IOptionHandler"/> delayed object
|
/// activation scheme. The <see cref="ActivateOptions"/> method must
|
/// be called on this object after the configuration properties have
|
/// been set. Until <see cref="ActivateOptions"/> is called this
|
/// object is in an undefined state and must not be used.
|
/// </para>
|
/// <para>
|
/// If any of the configuration properties are modified then
|
/// <see cref="ActivateOptions"/> must be called again.
|
/// </para>
|
/// <para>
|
/// Typically filter's options become active immediately on set,
|
/// however this method must still be called.
|
/// </para>
|
/// </remarks>
|
virtual public void ActivateOptions()
|
{
|
}
|
|
#endregion
|
|
#region Implementation of IFilter
|
|
/// <summary>
|
/// Decide if the <see cref="LoggingEvent"/> should be logged through an appender.
|
/// </summary>
|
/// <param name="loggingEvent">The <see cref="LoggingEvent"/> to decide upon</param>
|
/// <returns>The decision of the filter</returns>
|
/// <remarks>
|
/// <para>
|
/// If the decision is <see cref="FilterDecision.Deny"/>, then the event will be
|
/// dropped. If the decision is <see cref="FilterDecision.Neutral"/>, then the next
|
/// filter, if any, will be invoked. If the decision is <see cref="FilterDecision.Accept"/> then
|
/// the event will be logged without consulting with other filters in
|
/// the chain.
|
/// </para>
|
/// <para>
|
/// This method is marked <c>abstract</c> and must be implemented
|
/// in a subclass.
|
/// </para>
|
/// </remarks>
|
abstract public FilterDecision Decide(LoggingEvent loggingEvent);
|
|
/// <summary>
|
/// Property to get and set the next filter
|
/// </summary>
|
/// <value>
|
/// The next filter in the chain
|
/// </value>
|
/// <remarks>
|
/// <para>
|
/// Filters are typically composed into chains. This property allows the next filter in
|
/// the chain to be accessed.
|
/// </para>
|
/// </remarks>
|
public IFilter Next
|
{
|
get { return m_next; }
|
set { m_next = value; }
|
}
|
|
#endregion
|
}
|
}
|
