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package org.apache.tomcat.util.handler;
import java.io.*;
import java.util.*;
import java.security.*;
/**
* The lowest level component of Jk ( and hopefully Coyote ).
*
* Try to keep it minimal and flexible - add only if you _have_ to add.
*
* It is similar in concept and can implement/wrap tomcat3.3 Interceptor, tomcat4.0 Valve,
* axis Handler, tomcat3.3 Handler, apache2 Hooks etc.
*
* Both iterative (Interceptor, Hook ) and recursive ( Valve ) behavior are supported.
* Named TcHandler because Handler name is too overloaded.
*
* The interface allows both stateless and statefull implementations ( like Servlet ).
*
* @author Costin Manolache
*/
public abstract class TcHandler {
public static final int OK=0;
public static final int LAST=1;
public static final int ERROR=2;
protected Hashtable attributes=new Hashtable();
protected TcHandler next;
protected String name;
protected int id;
// -------------------- Configuration --------------------
/** Set the name of the handler. Will allways be called by
* worker env after creating the worker.
*/
public void setName(String s ) {
name=s;
}
public String getName() {
return name;
}
/** Set the id of the worker. It can be used for faster dispatch.
* Must be unique, managed by whoever creates the handlers.
*/
public void setId( int id ) {
this.id=id;
}
public int getId() {
return id;
}
/** Catalina-style "recursive" invocation. A handler is required to call
* the next handler if set.
*/
public void setNext( TcHandler h ) {
next=h;
}
/** Base implementation will just save all attributes.
* It is higly desirable to override this and allow runtime reconfiguration.
* XXX Should I make it abstract and force everyone to override ?
*/
public void setAttribute( String name, Object value ) {
attributes.put( name, value );
}
/** Get an attribute. Override to allow runtime query ( attribute can be
* anything, including statistics, etc )
*/
public Object getAttribute( String name ) {
return attributes.get(name) ;
}
//-------------------- Lifecycle --------------------
/** Should register the request types it can handle,
* same style as apache2.
*/
public void init() throws IOException {
}
/** Clean up and stop the handler. Override if needed.
*/
public void destroy() throws IOException {
}
public void start() throws IOException {
}
public void stop() throws IOException {
}
// -------------------- Action --------------------
/** The 'hook' method. If a 'next' was set, invoke should call it ( recursive behavior,
* similar with valve ).
*
* The application using the handler can also iterate, using the same semantics with
* Interceptor or APR hooks.
*
* @returns OK, LAST, ERROR Status of the execution, semantic similar with apache
*/
public abstract int invoke(TcHandlerCtx tcCtx) throws IOException;
}