/* -*- C++ -*- */
// URL_Visitor.h,v 1.10 2003/11/09 04:12:09 dhinton Exp
// ============================================================================
//
// = LIBRARY
// examples/Web_Crawler
//
// = FILENAME
// URL_Visitor.h
//
// = AUTHOR
// Douglas C.Schmidt <schmidt@cs.wustl.edu>
// Kirthika Parameswaran <kirthika@cs.wustl.edu>
// ============================================================================
#ifndef _URL_VISITOR_H
#define _URL_VISITOR_H
#include /**/ "ace/pre.h"
#include "ace/Strategies_T.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
#pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#include "HTTP_URL.h"
#include "Iterators.h"
#include "ace/Hash_Map_Manager_T.h"
#include "ace/Caching_Strategies_T.h"
#include "ace/Cached_Connect_Strategy_T.h"
#include "Options.h"
#include "ace/Pair_T.h"
// Forward declarations.
class URL_Validation_Visitor;
class URL_Processing_Strategy
{
// = TITLE
// Abstract base class for the URL processing strategy.
//
// = DESCRIPTION
public:
URL_Processing_Strategy (URL &,
URL_Iterator &);
// Constructor.
virtual int execute (void) = 0;
// Perform the strategy.
virtual int destroy (void);
// Close down the resources.
protected:
URL &url_;
// A reference to the URL "context" that we're processing.
URL_Iterator &iterator_;
// Iterator for the URL that we're processing.
};
class HTTP_Header_Processing_Strategy : public URL_Processing_Strategy
{
// = TITLE
// Defines the HTTP header processing strategy.
//
// = DESCRIPTION
public:
HTTP_Header_Processing_Strategy (URL &,
URL_Iterator &);
// Constructor.
virtual int execute (void);
// Perform the strategy for processing an HTTP header.
};
class HTML_Body_Validation_Strategy : public URL_Processing_Strategy
{
// = TITLE
// Defines the HTML body processing strategy.
//
// = DESCRIPTION
// This class iterates through the body of an HTML file and
// recursively visits embedded links.
public:
HTML_Body_Validation_Strategy (URL &,
URL_Iterator &,
URL_Validation_Visitor &);
// Constructor.
virtual int execute (void);
// Perform the strategy for processing an HTML file. This strategy
// iterates over the HTML file and recursively visits embedded links
// to process them, as well.
private:
URL_Validation_Visitor &visitor_context_;
// This is the context of the visit.
};
class URL_Download_Strategy : public URL_Processing_Strategy
{
// = TITLE
// Defines a URL downloading strategy.
//
// = DESCRIPTION
// This class downloads a URL's contents into a temporary file.
public:
URL_Download_Strategy (URL &,
URL_Iterator &);
// Constructor.
virtual int execute (void);
// Perform the strategy for downloading a URL to a temporary file.
};
class URL_Visitation_Strategy_Factory
{
// = TITLE
// Abstract Factory for the URL visitation strategy.
//
// = DESCRIPTION
public:
URL_Visitation_Strategy_Factory (URL *);
// = Factory Methods.
virtual URL_Iterator *make_header_iterator (void) = 0;
// Factory Method that makes the header iterator.
virtual URL_Iterator *make_body_iterator (void) = 0;
// Factory Method that makes the body iterator.
virtual URL_Processing_Strategy *make_header_strategy (URL_Iterator &) = 0;
// Factory Method that makes the header processing strategy.
virtual URL_Processing_Strategy *make_body_strategy (URL_Iterator &) = 0;
// Factory Method that makes the body processing strategy .
virtual int destroy (void) = 0;
// Close down the resources.
protected:
URL *url_;
// Stash the URL so we don't have to pass it around.
};
class URL_Download_Visitation_Strategy_Factory : public URL_Visitation_Strategy_Factory
{
// = TITLE
// Concrete Factory for the URL validation visitation strategy.
//
// = DESCRIPTION
public:
URL_Download_Visitation_Strategy_Factory (URL *);
// Constructor.
// = Factory Methods.
virtual URL_Iterator *make_header_iterator (void);
// Factory Method that makes an <HTTP_Header_Iterator>.
virtual URL_Iterator *make_body_iterator (void);
// Factory Method that makes an <HTML_Body_Iterator>.
virtual URL_Processing_Strategy *make_header_strategy (URL_Iterator &);
// Factory Method that makes the header processing strategy.
virtual URL_Processing_Strategy *make_body_strategy (URL_Iterator &);
// Factory Method that makes the body processing strategy .
virtual int destroy (void);
// Close down the resources.
};
class URL_Validation_Visitation_Strategy_Factory : public URL_Visitation_Strategy_Factory
{
// = TITLE
// Concrete Factory for the URL validation visitation strategy.
//
// = DESCRIPTION
public:
URL_Validation_Visitation_Strategy_Factory (URL *,
URL_Validation_Visitor &);
// Constructor.
// = Factory Methods.
virtual URL_Iterator *make_header_iterator (void);
// Factory Method that makes an <HTTP_Header_Iterator>.
virtual URL_Iterator *make_body_iterator (void);
// Factory Method that makes an <HTML_Body_Iterator>.
virtual URL_Processing_Strategy *make_header_strategy (URL_Iterator &);
// Factory Method that makes the header processing strategy.
virtual URL_Processing_Strategy *make_body_strategy (URL_Iterator &);
// Factory Method that makes the body processing strategy .
virtual int destroy (void);
// Close down the resources.
private:
URL_Validation_Visitor &visitor_context_;
// Context of the visitor.
};
class URL_Visitor
{
// = TITLE
// Base class for the URL Visitor.
//
// = DESCRIPTION
// This class plays the "visitor" role in the Visitor pattern.
public:
virtual int visit (HTTP_URL &http_url) = 0;
// Visit an <HTTP_URL>.
// @@
// virtual int visit (FTP_URL &http_url) = 0;
virtual int destroy (void) = 0;
// Cleanup the resources.
protected:
virtual URL_Visitation_Strategy_Factory *make_visitation_strategy_factory (URL &) = 0;
// Make the appropriate <URL_Visitation_Strategy_Factory>.
};
typedef int ATTRIBUTES;
typedef ACE_Svc_Handler <ACE_SOCK_STREAM, ACE_NULL_SYNCH>
Client_Svc_Handler;
typedef ACE_Pair<Client_Svc_Handler *, ATTRIBUTES>
CACHED_HANDLER;
typedef ACE_Refcounted_Hash_Recyclable<ACE_INET_Addr>
ACE_ADDR;
typedef ACE_Hash<ACE_ADDR> H_KEY;
typedef ACE_Equal_To<ACE_ADDR> C_KEYS;
typedef ACE_Hash_Map_Manager_Ex<ACE_ADDR, CACHED_HANDLER, H_KEY, C_KEYS, ACE_Null_Mutex>
HASH_MAP;
typedef ACE_Hash_Map_Iterator_Ex<ACE_ADDR, CACHED_HANDLER, H_KEY, C_KEYS, ACE_Null_Mutex>
HASH_MAP_ITERATOR;
typedef ACE_Hash_Map_Reverse_Iterator_Ex<ACE_ADDR, CACHED_HANDLER, H_KEY, C_KEYS, ACE_Null_Mutex>
HASH_MAP_REVERSE_ITERATOR;
typedef ACE_Recyclable_Handler_Cleanup_Strategy<ACE_ADDR, CACHED_HANDLER, HASH_MAP>
CLEANUP_STRATEGY;
typedef ACE_Recyclable_Handler_Caching_Utility<ACE_ADDR, CACHED_HANDLER, HASH_MAP, HASH_MAP_ITERATOR, ATTRIBUTES>
CACHING_UTILITY;
typedef ACE_LRU_Caching_Strategy<ATTRIBUTES, CACHING_UTILITY>
LRU_CACHING_STRATEGY;
//#if defined (ACE_HAS_BROKEN_EXTENDED_TEMPLATES)
typedef LRU_CACHING_STRATEGY
CACHING_STRATEGY;
//#else
//typedef ACE_Caching_Strategy_Adapter<ATTRIBUTES, CACHING_UTILITY, LRU_CACHING_STRATEGY>
// LRU_CACHING_STRATEGY_ADAPTER;
//typedef ACE_Caching_Strategy<ATTRIBUTES, CACHING_UTILITY>
// CACHING_STRATEGY;
//#endif /* ACE_HAS_BROKEN_EXTENDED_TEMPLATES */
typedef ACE_Strategy_Connector<Client_Svc_Handler, ACE_SOCK_CONNECTOR>
STRATEGY_CONNECTOR;
typedef ACE_NOOP_Creation_Strategy<Client_Svc_Handler>
NULL_CREATION_STRATEGY;
typedef ACE_NOOP_Concurrency_Strategy<Client_Svc_Handler>
NULL_ACTIVATION_STRATEGY;
typedef ACE_Cached_Connect_Strategy_Ex<Client_Svc_Handler, ACE_SOCK_CONNECTOR, CACHING_STRATEGY, ATTRIBUTES, ACE_SYNCH_NULL_MUTEX>
CACHED_CONNECT_STRATEGY;
class URL_Validation_Visitor : public URL_Visitor
{
// = TITLE
// Subclass that defines the URL validation visitor.
//
// = DESCRIPTION
// This class checks to make sure that the <HTTP_URL> is valid.
// If the <HTTP_URL> is an <HTML> file, it can also be used to
// recursively check that all embedded links in this file are
// valid.
public:
typedef ACE_Hash_Map_Manager <ACE_URL_Addr, URL_Status, ACE_Null_Mutex>
URL_CACHE;
virtual int visit (HTTP_URL &http_url);
// Visit an <HTTP_URL> to make sure that it's valid. If the content
// type of the <HTTP_URL> is "text/html" and the <recursion> option
// is enabled then <visit> recursively checks each link embedded in
// the HTML page.
// @@
// virtual int visit (FTP_URL &http_url);
URL_Validation_Visitor (void);
virtual int destroy (void);
// Cleanup the resources.
URL_CACHE &url_cache (void);
// Returns a reference to the URL cache.
/*
typedef ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_NULL_SYNCH>
Svc_Handler;
typedef ACE_Strategy_Connector<Svc_Handler, ACE_SOCK_CONNECTOR>
STRAT_CONNECTOR;
typedef ACE_Refcounted_Hash_Recyclable<ACE_INET_Addr>
REFCOUNTED_HASH_RECYCLABLE_ADDRESS;
typedef ACE_NOOP_Creation_Strategy<Svc_Handler>
NULL_CREATION_STRATEGY;
typedef ACE_NOOP_Concurrency_Strategy<Svc_Handler>
NULL_ACTIVATION_STRATEGY;
typedef ACE_Hash_Map_Manager_Ex<REFCOUNTED_HASH_RECYCLABLE_ADDRESS,\
ACE_Pair<Svc_Handler *, int>,\
ACE_Hash<REFCOUNTED_HASH_RECYCLABLE_ADDRESS>, \
ACE_Equal_To<REFCOUNTED_HASH_RECYCLABLE_ADDRESS>,\
ACE_Null_Mutex>
CONNECTION_HASH_MAP;
typedef ACE_Hash_Map_Iterator_Ex<REFCOUNTED_HASH_RECYCLABLE_ADDRESS,\
ACE_Pair<Svc_Handler *, int>,\
ACE_Hash<REFCOUNTED_HASH_RECYCLABLE_ADDRESS>, \
ACE_Equal_To<REFCOUNTED_HASH_RECYCLABLE_ADDRESS>,\
ACE_Null_Mutex>
CONNECTION_HASH_MAP_ITERATOR;
typedef ACE_Hash_Map_Reverse_Iterator_Ex<REFCOUNTED_HASH_RECYCLABLE_ADDRESS,\
ACE_Pair<Svc_Handler *, int>,\
ACE_Hash<REFCOUNTED_HASH_RECYCLABLE_ADDRESS>, \
ACE_Equal_To<REFCOUNTED_HASH_RECYCLABLE_ADDRESS>,\
ACE_Null_Mutex>
CONNECTION_HASH_MAP_REVERSE_ITERATOR;
typedef ACE_Pair_Caching_Utility <REFCOUNTED_HASH_RECYCLABLE_ADDRESS, \
ACE_Pair<Svc_Handler *, int>, \
CONNECTION_HASH_MAP, CONNECTION_HASH_MAP_ITERATOR, int >
CACHING_STRATEGY_UTILITY;
typedef ACE_LRU_Caching_Strategy<REFCOUNTED_HASH_RECYCLABLE_ADDRESS,\
ACE_Pair<Svc_Handler *, int>,\
CONNECTION_HASH_MAP, int,\
CACHING_STRATEGY_UTILITY >
LRU;
typedef ACE_Cached_Connect_Strategy_Ex<Svc_Handler,ACE_SOCK_CONNECTOR, LRU,int, ACE_SYNCH_NULL_MUTEX>
CACHED_CONNECT_STRATEGY;
*/
protected:
virtual ~URL_Validation_Visitor (void);
virtual URL_Visitation_Strategy_Factory *make_visitation_strategy_factory (URL &);
// Factory Method that makes a
// <URL_Validation_Visitation_Strategy_Factory>.
URL_CACHE url_cache_;
// Cache the status of URLs we've already validated.
int in_cache (const ACE_URL_Addr &url_addr);
// Check to see if the reply status of this <url_addr> is in the
// cache. Returns 1 if so, 0 if not.
NULL_CREATION_STRATEGY creation_strategy_;
NULL_ACTIVATION_STRATEGY activation_strategy_;
// Configure the Strategy Connector with a strategy that caches
// connection.
CACHED_CONNECT_STRATEGY *caching_connect_strategy_;
STRATEGY_CONNECTOR *strat_connector_;
CACHING_STRATEGY caching_strategy_;
};
class URL_Download_Visitor : public URL_Visitor
{
// = TITLE
// Subclass for the URL validtion visitor.
//
// = DESCRIPTION
// This class checks to make sure that the <HTTP_URL> is valid.
public:
virtual int visit (HTTP_URL &http_url);
// Visit an <HTTP_URL> to make sure that it's valid. If the content
// type of the <HTTP_URL> is "text/html" and the <recursion> option
// is enabled then <visit> recursively checks each link embedded in
// the HTML page.
// @@
// virtual int visit (FTP_URL &http_url);
virtual int destroy (void);
// Cleanup the resources.
protected:
URL_Visitation_Strategy_Factory *make_visitation_strategy_factory (URL &);
// Factory Method that makes a <URL_Download_Visitation_Strategy_Factory>.
};
template <class T>
class Auto_Destroyer
{
// = TITLE
// Simple class that ensures the <destroy> method is called on our
// <URL_*> objects when they go out of scope.
//
// = DESCRIPTION
// This class is similar to an auto_ptr<> and should be used to
// simplify blocks of code that must create/destroy pointers to
// various <URL_*> related strategies and iterators.
public:
Auto_Destroyer (T *t): t_ (t) {}
T *operator-> (void) { return this->t_; }
T *operator *(void) { return this->t_; }
void operator= (T *t)
{
if (this->t_ != 0)
this->t_->destroy ();
this->t_ = t;
}
~Auto_Destroyer (void)
{
if (this->t_ != 0)
t_->destroy ();
}
private:
T *t_;
};
#include /**/ "ace/post.h"
#endif /* _URL_VISITOR_H */
