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/*
* 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.
*/
package javax.servlet;
import java.io.Serializable;
import java.util.Enumeration;
/**
* Provides a base class that implements the Filter and FilterConfig interfaces
* to reduce boilerplate when writing new filters.
*
* @see javax.servlet.Filter
* @see javax.servlet.FilterConfig
*
* @since Servlet 4.0
*/
public abstract class GenericFilter implements Filter, FilterConfig, Serializable {
private static final long serialVersionUID = 1L;
/**
* The filter configuration.
*/
private volatile FilterConfig filterConfig;
@Override
public String getInitParameter(String name) {
return getFilterConfig().getInitParameter(name);
}
@Override
public Enumeration<String> getInitParameterNames() {
return getFilterConfig().getInitParameterNames();
}
/**
* Obtain the FilterConfig used to initialise this Filter instance.
*
* @return The config previously passed to the {@link #init(FilterConfig)}
* method
*/
public FilterConfig getFilterConfig() {
return filterConfig;
}
@Override
public ServletContext getServletContext() {
return getFilterConfig().getServletContext();
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
this.filterConfig = filterConfig;
init();
}
/**
* Convenience method for sub-classes to save them having to call
* <code>super.init(config)</code>. This is a NO-OP by default.
*
* @throws ServletException If an exception occurs that interrupts the
* Filter's normal operation
*/
public void init() throws ServletException {
// NO-OP
}
@Override
public String getFilterName() {
return getFilterConfig().getFilterName();
}
}
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