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| Intercepting Filter Design Pattern - Implementation |
Filter.Java
public interface Filter
{
public void processRequest(String request);
}
AuthenticationFilter.java
public class AuthenticationFilter implements Filter
{
@Override
public void processRequest( String request )
{
System.out.println("Authenticating the request by AuthenticationFilter : " + request);
}
}
LoggingFilter.java
public class LoggingFilter implements Filter
{
@Override
public void processRequest( String request )
{
System.out.println("Request Tracking is done by LoggingFilter : " + request);
}
}
Target.java
public class Target
{
public void processRequest( String request )
{
System.out.println("Process the Request by Target Class: " + request);
}
}
FilterChain.java
import java.util.ArrayList;
import java.util.List;
public class FilterChain
{
private List<Filter> filters = new ArrayList<Filter>();
private Target target;
public void addFilter( Filter filter )
{
filters.add(filter);
}
public void execute( String request )
{
for( Filter filter : filters )
{
filter.processRequest(request);
}
target.processRequest(request);
}
public void setTarget( Target target )
{
this.target = target;
}
}
FilterManager.java
public class FilterManager
{
FilterChain filterChain;
public FilterManager( Target target )
{
filterChain = new FilterChain();
filterChain.setTarget(target);
}
public void setFilter( Filter filter )
{
filterChain.addFilter(filter);
}
public void filterRequest( String request )
{
filterChain.execute(request);
}
}
Client.java
public class Client
{
FilterManager filterManager;
public void setFilterManager( FilterManager filterManager )
{
this.filterManager = filterManager;
}
public void sendRequest( String request )
{
filterManager.filterRequest(request);
}
public static void main( String[] args )
{
FilterManager filterManager = new FilterManager(new Target());
filterManager.setFilter(new AuthenticationFilter());
filterManager.setFilter(new LoggingFilter());
Client client = new Client();
client.setFilterManager(filterManager);
client.sendRequest("HOME");
}
}
Output
Authenticating the request by AuthenticationFilter : HOME
Request Tracking is done by LoggingFilter : HOME
Process the Request by Target Class: HOME
See also:
Intercepting Filter Design Pattern - Introduction
Intercepting Filter Design Pattern - Class and Sequence Diagram
Intercepting Filter Design Pattern - KeyPoints
All Design Patterns Links
See also:
Why don't you create a login/authentication app and show the real implementation of Filters?
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