Prototype

Prototype Design Pattern

Definition:
Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype. -- "Design Patterns" Gamma et al., Addison-Wesley, ISBN:0-201-63361-2" 

Friendly Definition:
Prototype pattern is a creational pattern. Meaning it deals with the most efficient ways to create object in a given situation. when you do not want to directly call an objects' constructor , you can use this pattern to clone an existing object of that class thus reducing the number of classes. The basic principle behind this pattern is to determine the type of objects to be created by using a prototypical reference.

Pattern diagram

Sample code

Java Sample: Prototype pattern in java is implemented using the Clonable interface which provides the clone() method. Cloneable is an empty interface. It simply acts as a tag to indicate that the implementing classes need their instances to support clonning. Subclasses must implement the Clonable interface and then override the clone() method and call the super classes clone method in the implementation of overridden clone method using super.clone() statement.If you don't implement Cloneable, the super.clone() implementation will throw a CloneNotSupportedException.

The following is the implementation of Cookie class in apache tomcat server. This class makes use of prototype pattern and Clonable interface to create clones of cookie object.

apache-tomcat-6.0.10 - Cookie.java

/*
* 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.http;

import java.text.MessageFormat;
import java.util.ResourceBundle;

/**
 *
 * Creates a cookie, a small amount of information sent by a servlet to
 * a Web browser, saved by the browser, and later sent back to the server.
 * A cookie's value can uniquely
 * identify a client, so cookies are commonly used for session management.
 *
 * <p>A cookie has a name, a single value, and optional attributes
 * such as a comment, path and domain qualifiers, a maximum age, and a
 * version number. Some Web browsers have bugs in how they handle the
 * optional attributes, so use them sparingly to improve the interoperability
 * of your servlets.
 *
 * <p>The servlet sends cookies to the browser by using the
 * {@link HttpServletResponse#addCookie} method, which adds
 * fields to HTTP response headers to send cookies to the
 * browser, one at a time. The browser is expected to
 * support 20 cookies for each Web server, 300 cookies total, and
 * may limit cookie size to 4 KB each.
 *
 * <p>The browser returns cookies to the servlet by adding
 * fields to HTTP request headers. Cookies can be retrieved
 * from a request by using the {@link HttpServletRequest#getCookies} method.
 * Several cookies might have the same name but different path attributes.
 *
 * <p>Cookies affect the caching of the Web pages that use them.
 * HTTP 1.0 does not cache pages that use cookies created with
 * this class. This class does not support the cache control
 * defined with HTTP 1.1.
 *
 * <p>This class supports both the Version 0 (by Netscape) and Version 1
 * (by RFC 2109) cookie specifications. By default, cookies are
 * created using Version 0 to ensure the best interoperability.
 *
 *
 * @author	Various
 * @version	$Version$
 *
 */

// XXX would implement java.io.Serializable too, but can't do that
// so long as sun.servlet.* must run on older JDK 1.02 JVMs which
// don't include that support.

public class Cookie implements Cloneable {

    private static final String LSTRING_FILE =
	"javax.servlet.http.LocalStrings";
    private static ResourceBundle lStrings =
	ResourceBundle.getBundle(LSTRING_FILE);

    //
    // The value of the cookie itself.
    //

    private String name;	// NAME= ... "$Name" style is reserved
    private String value;	// value of NAME

    //
    // Attributes encoded in the header's cookie fields.
    //

    private String comment;	// ;Comment=VALUE ... describes cookie's use
				// ;Discard ... implied by maxAge < 0
    private String domain;	// ;Domain=VALUE ... domain that sees cookie
    private int maxAge = -1;	// ;Max-Age=VALUE ... cookies auto-expire
    private String path;	// ;Path=VALUE ... URLs that see the cookie
    private boolean secure;	// ;Secure ... e.g. use SSL
    private int version = 0;	// ;Version=1 ... means RFC 2109++ style



    /**
     * Constructs a cookie with a specified name and value.
     *
     * <p>The name must conform to RFC 2109. That means it can contain
     * only ASCII alphanumeric characters and cannot contain commas,
     * semicolons, or white space or begin with a $ character. The cookie's
     * name cannot be changed after creation.
     *
     * <p>The value can be anything the server chooses to send. Its
     * value is probably of interest only to the server. The cookie's
     * value can be changed after creation with the
     * <code>setValue</code> method.
     *
     * <p>By default, cookies are created according to the Netscape
     * cookie specification. The version can be changed with the
     * <code>setVersion</code> method.
     *
     *
     * @param name 			a <code>String</code> specifying the name of the cookie
     *
     * @param value			a <code>String</code> specifying the value of the cookie
     *
     * @throws IllegalArgumentException	if the cookie name contains illegal characters
     *					(for example, a comma, space, or semicolon)
     *					or it is one of the tokens reserved for use
     *					by the cookie protocol
     * @see #setValue
     * @see #setVersion
     *
     */

    public Cookie(String name, String value) {
	if (!isToken(name)
		|| name.equalsIgnoreCase("Comment")	// rfc2019
		|| name.equalsIgnoreCase("Discard")	// 2019++
		|| name.equalsIgnoreCase("Domain")
		|| name.equalsIgnoreCase("Expires")	// (old cookies)
		|| name.equalsIgnoreCase("Max-Age")	// rfc2019
		|| name.equalsIgnoreCase("Path")
		|| name.equalsIgnoreCase("Secure")
		|| name.equalsIgnoreCase("Version")
		|| name.startsWith("$")
	    ) {
	    String errMsg = lStrings.getString("err.cookie_name_is_token");
	    Object[] errArgs = new Object[1];
	    errArgs[0] = name;
	    errMsg = MessageFormat.format(errMsg, errArgs);
	    throw new IllegalArgumentException(errMsg);
	}

	this.name = name;
	this.value = value;
    }

    /**
     *
     * Specifies a comment that describes a cookie's purpose.
     * The comment is useful if the browser presents the cookie
     * to the user. Comments
     * are not supported by Netscape Version 0 cookies.
     *
     * @param purpose		a <code>String</code> specifying the comment
     *				to display to the user
     *
     * @see #getComment
     *
     */

    public void setComment(String purpose) {
	comment = purpose;
    }


    /**
     * Returns the comment describing the purpose of this cookie, or
     * <code>null</code> if the cookie has no comment.
     *
     * @return			a <code>String</code> containing the comment,
     *				or <code>null</code> if none
     *
     * @see #setComment
     *
     */

    public String getComment() {
	return comment;
    }


    /**
     *
     * Specifies the domain within which this cookie should be presented.
     *
     * <p>The form of the domain name is specified by RFC 2109. A domain
     * name begins with a dot (<code>.foo.com</code>) and means that
     * the cookie is visible to servers in a specified Domain Name System
     * (DNS) zone (for example, <code>www.foo.com</code>, but not
     * <code>a.b.foo.com</code>). By default, cookies are only returned
     * to the server that sent them.
     *
     *
     * @param pattern		a <code>String</code> containing the domain name
     *				within which this cookie is visible;
     *				form is according to RFC 2109
     *
     * @see #getDomain
     *
     */

    public void setDomain(String pattern) {
	domain = pattern.toLowerCase();	// IE allegedly needs this
    }

    /**
     * Returns the domain name set for this cookie. The form of
     * the domain name is set by RFC 2109.
     *
     * @return			a <code>String</code> containing the domain name
     *
     * @see #setDomain
     *
     */

    public String getDomain() {
	return domain;
    }

    /**
     * Sets the maximum age of the cookie in seconds.
     *
     * <p>A positive value indicates that the cookie will expire
     * after that many seconds have passed. Note that the value is
     * the <i>maximum</i> age when the cookie will expire, not the cookie's
     * current age.
     *
     * <p>A negative value means
     * that the cookie is not stored persistently and will be deleted
     * when the Web browser exits. A zero value causes the cookie
     * to be deleted.
     *
     * @param expiry		an integer specifying the maximum age of the
     * 				cookie in seconds; if negative, means
     *				the cookie is not stored; if zero, deletes
     *				the cookie
     *
     *
     * @see #getMaxAge
     *
     */

    public void setMaxAge(int expiry) {
	maxAge = expiry;
    }

    /**
     * Returns the maximum age of the cookie, specified in seconds,
     * By default, <code>-1</code> indicating the cookie will persist
     * until browser shutdown.
     *
     *
     * @return			an integer specifying the maximum age of the
     *				cookie in seconds; if negative, means
     *				the cookie persists until browser shutdown
     *
     *
     * @see #setMaxAge
     *
     */

    public int getMaxAge() {
	return maxAge;
    }

    /**
     * Specifies a path for the cookie
     * to which the client should return the cookie.
     *
     * <p>The cookie is visible to all the pages in the directory
     * you specify, and all the pages in that directory's subdirectories.
     * A cookie's path must include the servlet that set the cookie,
     * for example, <i>/catalog</i>, which makes the cookie
     * visible to all directories on the server under <i>/catalog</i>.
     *
     * <p>Consult RFC 2109 (available on the Internet) for more
     * information on setting path names for cookies.
     *
     *
     * @param uri		a <code>String</code> specifying a path
     *
     *
     * @see #getPath
     *
     */

    public void setPath(String uri) {
	path = uri;
    }

    /**
     * Returns the path on the server
     * to which the browser returns this cookie. The
     * cookie is visible to all subpaths on the server.
     *
     *
     * @return		a <code>String</code> specifying a path that contains
     *			a servlet name, for example, <i>/catalog</i>
     *
     * @see #setPath
     *
     */

    public String getPath() {
	return path;
    }

    /**
     * Indicates to the browser whether the cookie should only be sent
     * using a secure protocol, such as HTTPS or SSL.
     *
     * <p>The default value is <code>false</code>.
     *
     * @param flag	if <code>true</code>, sends the cookie from the browser
     *			to the server only when using a secure protocol;
     *			if <code>false</code>, sent on any protocol
     *
     * @see #getSecure
     *
     */

    public void setSecure(boolean flag) {
	secure = flag;
    }

    /**
     * Returns <code>true</code> if the browser is sending cookies
     * only over a secure protocol, or <code>false</code> if the
     * browser can send cookies using any protocol.
     *
     * @return		<code>true</code> if the browser uses a secure protocol;
     * 			 otherwise, <code>true</code>
     *
     * @see #setSecure
     *
     */

    public boolean getSecure() {
	return secure;
    }

    /**
     * Returns the name of the cookie. The name cannot be changed after
     * creation.
     *
     * @return		a <code>String</code> specifying the cookie's name
     *
     */

    public String getName() {
	return name;
    }

    /**
     *
     * Assigns a new value to a cookie after the cookie is created.
     * If you use a binary value, you may want to use BASE64 encoding.
     *
     * <p>With Version 0 cookies, values should not contain white
     * space, brackets, parentheses, equals signs, commas,
     * double quotes, slashes, question marks, at signs, colons,
     * and semicolons. Empty values may not behave the same way
     * on all browsers.
     *
     * @param newValue		a <code>String</code> specifying the new value
     *
     *
     * @see #getValue
     * @see Cookie
     *
     */

    public void setValue(String newValue) {
	value = newValue;
    }

    /**
     * Returns the value of the cookie.
     *
     * @return			a <code>String</code> containing the cookie's
     *				present value
     *
     * @see #setValue
     * @see Cookie
     *
     */

    public String getValue() {
	return value;
    }

    /**
     * Returns the version of the protocol this cookie complies
     * with. Version 1 complies with RFC 2109,
     * and version 0 complies with the original
     * cookie specification drafted by Netscape. Cookies provided
     * by a browser use and identify the browser's cookie version.
     *
     *
     * @return			0 if the cookie complies with the
     *				original Netscape specification; 1
     *				if the cookie complies with RFC 2109
     *
     * @see #setVersion
     *
     */

    public int getVersion() {
	return version;
    }

    /**
     * Sets the version of the cookie protocol this cookie complies
     * with. Version 0 complies with the original Netscape cookie
     * specification. Version 1 complies with RFC 2109.
     *
     * <p>Since RFC 2109 is still somewhat new, consider
     * version 1 as experimental; do not use it yet on production sites.
     *
     *
     * @param v			0 if the cookie should comply with
     *				the original Netscape specification;
     *				1 if the cookie should comply with RFC 2109
     *
     * @see #getVersion
     *
     */

    public void setVersion(int v) {
	version = v;
    }

    // Note -- disabled for now to allow full Netscape compatibility
    // from RFC 2068, token special case characters
    //
    // private static final String tspecials = "()<>@,;:\\\"/[]?={} \t";

    private static final String tspecials = ",; ";

    /*
     * Tests a string and returns true if the string counts as a
     * reserved token in the Java language.
     *
     * @param value		the <code>String</code> to be tested
     *
     * @return			<code>true</code> if the <code>String</code> is
     *				a reserved token; <code>false</code>
     *				if it is not
     */

    private boolean isToken(String value) {
	int len = value.length();

	for (int i = 0; i < len; i++) {
	    char c = value.charAt(i);

	    if (c < 0x20 || c >= 0x7f || tspecials.indexOf(c) != -1)
		return false;
	}
	return true;
    }

    /**
     *
     * Overrides the standard <code>java.lang.Object.clone</code>
     * method to return a copy of this cookie.
     *
     *
     */

    public Object clone() {
	try {
	    return super.clone();
	} catch (CloneNotSupportedException e) {
	    throw new RuntimeException(e.getMessage());
	}
    }
}

---

C++ Sample: The following classes are a sample of prototype pattern implementation from gimp-2.3.15 open source graphice application. the prototypical class is imap_object.c that defines the object_clone method.

imap_object.h

/*
 * This is a plug-in for the GIMP.
 *
 * Generates clickable image maps.
 *
 * Copyright (C) 1998-2005 Maurits Rijk  m.rijk@chello.nl
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#ifndef _IMAP_OBJECT_H
#define _IMAP_OBJECT_H

typedef struct Object_t Object_t;
typedef struct ObjectClass_t ObjectClass_t;
typedef struct ObjectList_t ObjectList_t;

#include "imap_edit_area_info.h"
#include "imap_menu_funcs.h"

struct Object_t {
   ObjectClass_t 	*class;
   ObjectList_t		*list;
   gint			 refcount;
   gboolean 		 selected;
   gboolean		 locked;
   gchar		*url;
   gchar 		*target;
   gchar 		*comment;
   gchar 		*mouse_over;
   gchar 		*mouse_out;
   gchar		*focus;
   gchar		*blur;
};

typedef void (*MoveSashFunc_t)(Object_t*, gint, gint);
typedef void (*OutputFunc_t)(gpointer, const char*, ...);

struct AreaInfoDialog_t;

struct ObjectClass_t {
   gchar		*name;
   AreaInfoDialog_t 	*info_dialog;
   GdkPixmap 		*icon;
   GdkBitmap 		*mask;

   gboolean (*is_valid)(Object_t *obj);
   void (*destruct)(Object_t *obj);
   Object_t* (*clone)(Object_t *obj);
   void (*assign)(Object_t *obj, Object_t *des);
   void (*normalize)(Object_t *obj);
   void (*draw)(Object_t *obj, GdkWindow *window, GdkGC* gc);
   void (*draw_sashes)(Object_t *obj, GdkWindow *window, GdkGC* gc);
   MoveSashFunc_t (*near_sash)(Object_t *obj, gint x, gint y);
   gboolean (*point_is_on)(Object_t *obj, gint x, gint y);
   void (*get_dimensions)(Object_t *obj, gint *x, gint *y, gint *width,
			  gint *height);
   void (*resize)(Object_t *obj, gint percentage_x, gint percentage_y);
   void (*move)(Object_t *obj, gint dx, gint dy);
   gpointer (*create_info_widget)(GtkWidget *frame);
   void (*update_info_widget)(Object_t *obj, gpointer data);
   void (*fill_info_tab)(Object_t *obj, gpointer data);
   void (*set_initial_focus)(Object_t *obj, gpointer data);
   void (*update)(Object_t *obj, gpointer data);
   void (*write_csim)(Object_t *obj, gpointer param, OutputFunc_t output);
   void (*write_cern)(Object_t *obj, gpointer param, OutputFunc_t output);
   void (*write_ncsa)(Object_t *obj, gpointer param, OutputFunc_t output);
   void (*do_popup)(Object_t *obj, GdkEventButton *event);

   const gchar* (*get_stock_icon_name)(void);
};

Object_t *object_ref(Object_t *obj);
void object_unref(Object_t *obj);
Object_t* object_init(Object_t *obj, ObjectClass_t *class);
Object_t* object_clone(Object_t *obj);
Object_t* object_assign(Object_t *src, Object_t *des);
void object_draw(Object_t *obj, GdkWindow *window);
void object_edit(Object_t *obj, gboolean add);
void object_select(Object_t *obj);
void object_unselect(Object_t *obj);
void object_move(Object_t *obj, gint dx, gint dy);
void object_remove(Object_t *obj);
void object_lock(Object_t *obj);
void object_unlock(Object_t *obj);
void object_set_url(Object_t *obj, const gchar *url);
void object_set_target(Object_t *obj, const gchar *target);
void object_set_comment(Object_t *obj, const gchar *comment);
void object_set_mouse_over(Object_t *obj, const gchar *mouse_over);
void object_set_mouse_out(Object_t *obj, const gchar *mouse_out);
void object_set_focus(Object_t *obj, const gchar *focus);
void object_set_blur(Object_t *obj, const gchar *blur);
gint object_get_position_in_list(Object_t *obj);

void object_emit_changed_signal(Object_t *obj);
void object_emit_geometry_signal(Object_t *obj);
void object_emit_update_signal(Object_t *obj);

#define object_is_valid(obj) \
	((obj)->class->is_valid(obj))

#define object_get_dimensions(obj, x, y, width, height) \
   	((obj)->class->get_dimensions((obj), (x), (y), (width), (height)))

#define object_normalize(obj) \
  	((obj)->class->normalize(obj))

#define object_resize(obj, per_x, per_y) \
	((obj)->class->resize((obj), (per_x), (per_y)))

#define object_update(obj, data) \
	((obj)->class->update((obj), (data)))

#define object_update_info_widget(obj, data) \
	((obj)->class->update_info_widget((obj), (data)))

#define object_fill_info_tab(obj, data) \
	((obj)->class->fill_info_tab((obj), (data)))

#define object_get_stock_icon_name(obj) \
	((obj)->class->get_stock_icon_name())

typedef struct {
   Object_t *obj;
   gboolean (*finish)(Object_t *obj, gint x, gint y);
   gboolean (*cancel)(GdkEventButton *event, Object_t *obj);
   Object_t* (*create_object)(gint x, gint y);
   void (*set_xy)(Object_t *obj, guint state, gint x, gint y);
} ObjectFactory_t;

gboolean object_on_button_press(GtkWidget *widget, GdkEventButton *event,
				gpointer data);

typedef struct {
   GList *list;
} ObjectListCallback_t;

struct ObjectList_t {
   GList *list;
   gboolean changed;
   ObjectListCallback_t changed_cb;
   ObjectListCallback_t update_cb;
   ObjectListCallback_t add_cb;
   ObjectListCallback_t remove_cb;
   ObjectListCallback_t select_cb;
   ObjectListCallback_t move_cb;
   ObjectListCallback_t geometry_cb;
};

ObjectList_t *make_object_list (void);
void object_list_destruct(ObjectList_t *list);
ObjectList_t *object_list_copy(ObjectList_t *des, ObjectList_t *src);
ObjectList_t *object_list_append_list(ObjectList_t *des, ObjectList_t *src);

void object_list_append(ObjectList_t *list, Object_t *object);
void object_list_prepend(ObjectList_t *list, Object_t *object);
void object_list_insert(ObjectList_t *list, gint position, Object_t *object);
void object_list_remove(ObjectList_t *list, Object_t *object);
void object_list_remove_link(ObjectList_t *list, GList *link);
void object_list_update(ObjectList_t *list, Object_t *object);
void object_list_draw(ObjectList_t *list, GdkWindow *window);
void object_list_draw_selected(ObjectList_t *list, GdkWindow *window);
Object_t *object_list_find(ObjectList_t *list, gint x, gint y);
Object_t *object_list_near_sash(ObjectList_t *list, gint x, gint y,
				MoveSashFunc_t *sash_func);

gint object_list_cut(ObjectList_t *list);
void object_list_copy_to_paste_buffer(ObjectList_t *list);
void object_list_paste(ObjectList_t *list);

void object_list_remove_all(ObjectList_t *list);
void object_list_delete_selected(ObjectList_t *list);
void object_list_edit_selected(ObjectList_t *list);
gint object_list_select_all(ObjectList_t *list);
void object_list_select_next(ObjectList_t *list);
void object_list_select_prev(ObjectList_t *list);
gint object_list_select_region(ObjectList_t *list, gint x, gint y, gint width,
			       gint height);
gint object_list_deselect_all(ObjectList_t *list, Object_t *exception);
gint object_list_nr_selected(ObjectList_t *list);
void object_list_resize(ObjectList_t *list, gint percentage_x,
			gint percentage_y);
void object_list_move_selected(ObjectList_t *list, gint dx, gint dy);
void object_list_move_up(ObjectList_t *list, Object_t *obj);
void object_list_move_down(ObjectList_t *list, Object_t *obj);
void object_list_move_selected_up(ObjectList_t *list);
void object_list_move_selected_down(ObjectList_t *list);
void object_list_move_to_front(ObjectList_t *list);
void object_list_send_to_back(ObjectList_t *list);

void object_list_write_csim(ObjectList_t *list, gpointer param,
			    OutputFunc_t output);
void object_list_write_cern(ObjectList_t *list, gpointer param,
			    OutputFunc_t output);
void object_list_write_ncsa(ObjectList_t *list, gpointer param,
			    OutputFunc_t output);

typedef void (*ObjectListCallbackFunc_t)(Object_t*, gpointer);

gpointer object_list_add_changed_cb(ObjectList_t *list,
				    ObjectListCallbackFunc_t func,
				    gpointer data);
gpointer object_list_add_update_cb(ObjectList_t *list,
				   ObjectListCallbackFunc_t func,
				   gpointer data);
gpointer object_list_add_add_cb(ObjectList_t *list,
				ObjectListCallbackFunc_t func, gpointer data);
gpointer object_list_add_remove_cb(ObjectList_t *list,
				   ObjectListCallbackFunc_t func,
				   gpointer data);
gpointer object_list_add_select_cb(ObjectList_t *list,
				   ObjectListCallbackFunc_t func,
				   gpointer data);
gpointer object_list_add_move_cb(ObjectList_t *list,
				 ObjectListCallbackFunc_t func, gpointer data);
gpointer object_list_add_geometry_cb(ObjectList_t *list,
				     ObjectListCallbackFunc_t func,
				     gpointer data);

void object_list_remove_add_cb(ObjectList_t *list, gpointer id);
void object_list_remove_select_cb(ObjectList_t *list, gpointer id);
void object_list_remove_remove_cb(ObjectList_t *list, gpointer id);
void object_list_remove_move_cb(ObjectList_t *list, gpointer id);
void object_list_remove_geometry_cb(ObjectList_t *list, gpointer id);

#define object_list_clear_changed(list) ((list)->changed = FALSE)
#define object_list_set_changed(list, ischanged) \
	((list)->changed = (ischanged))
#define object_list_get_changed(list) ((list)->changed)

void clear_paste_buffer(void);
gpointer paste_buffer_add_add_cb(ObjectListCallbackFunc_t func, gpointer data);
gpointer paste_buffer_add_remove_cb(ObjectListCallbackFunc_t func,
				    gpointer data);
ObjectList_t *get_paste_buffer(void);

void do_object_locked_dialog(void);

#endif /* _IMAP_OBJECT_H */

imap_object.c

/*
 * This is a plug-in for the GIMP.
 *
 * Generates clickable image maps.
 *
 * Copyright (C) 1998-2005 Maurits Rijk  m.rijk@chello.nl
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include "config.h"

#include <gtk/gtk.h>

#include "imap_commands.h"
#include "imap_default_dialog.h"
#include "imap_grid.h"
#include "imap_main.h"
#include "imap_object.h"
#include "imap_string.h"

static Object_t* object_factory_create_object (ObjectFactory_t *factory,
                                                gint x, gint y);


typedef struct {
   ObjectListCallbackFunc_t func;
   gpointer data;
} ObjectListCB_t;

static ObjectList_t *_paste_buffer;

static gpointer
object_list_callback_add(ObjectListCallback_t *list,
			 ObjectListCallbackFunc_t func, gpointer data)
{
   ObjectListCB_t *cb = g_new(ObjectListCB_t, 1);
   cb->func = func;
   cb->data = data;
   list->list = g_list_append(list->list, cb);
   return cb;
}

static void
object_list_callback_remove(ObjectListCallback_t *list, gpointer id)
{
   list->list = g_list_remove(list->list, id);
}

static void
object_list_callback_call(ObjectListCallback_t *list, Object_t *obj)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      ObjectListCB_t *cb = (ObjectListCB_t*) p->data;
      cb->func(obj, cb->data);
   }
}

gpointer
object_list_add_changed_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
			   gpointer data)
{
   return object_list_callback_add(&list->changed_cb, func, data);
}

gpointer
object_list_add_update_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
			  gpointer data)
{
   return object_list_callback_add(&list->update_cb, func, data);
}

gpointer
object_list_add_add_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
		       gpointer data)
{
   return object_list_callback_add(&list->add_cb, func, data);
}

gpointer
object_list_add_remove_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
			  gpointer data)
{
   return object_list_callback_add(&list->remove_cb, func, data);
}

gpointer
object_list_add_select_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
			  gpointer data)
{
   return object_list_callback_add(&list->select_cb, func, data);
}

gpointer
object_list_add_move_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
			gpointer data)
{
   return object_list_callback_add(&list->move_cb, func, data);
}

gpointer
object_list_add_geometry_cb(ObjectList_t *list, ObjectListCallbackFunc_t func,
			    gpointer data)
{
   return object_list_callback_add(&list->geometry_cb, func, data);
}

gpointer
paste_buffer_add_add_cb(ObjectListCallbackFunc_t func, gpointer data)
{
   if (!_paste_buffer)
      _paste_buffer = make_object_list();
   return object_list_callback_add(&_paste_buffer->add_cb, func, data);
}

gpointer
paste_buffer_add_remove_cb(ObjectListCallbackFunc_t func, gpointer data)
{
   if (!_paste_buffer)
      _paste_buffer = make_object_list();
   return object_list_callback_add(&_paste_buffer->remove_cb, func, data);
}

void
object_list_remove_add_cb(ObjectList_t *list, gpointer id)
{
   object_list_callback_remove(&list->add_cb, id);
}

void
object_list_remove_select_cb(ObjectList_t *list, gpointer id)
{
   object_list_callback_remove(&list->select_cb, id);
}

void
object_list_remove_remove_cb(ObjectList_t *list, gpointer id)
{
   object_list_callback_remove(&list->remove_cb, id);
}

void
object_list_remove_move_cb(ObjectList_t *list, gpointer id)
{
   object_list_callback_remove(&list->move_cb, id);
}

void
object_list_remove_geometry_cb(ObjectList_t *list, gpointer id)
{
   object_list_callback_remove(&list->geometry_cb, id);
}

Object_t*
object_init(Object_t *obj, ObjectClass_t *class)
{
   obj->class = class;
   obj->refcount = 1;
   obj->selected = FALSE;
   obj->locked = FALSE;
   obj->url = g_strdup("");
   obj->target = g_strdup("");
   obj->comment = g_strdup("");
   obj->mouse_over = g_strdup("");
   obj->mouse_out = g_strdup("");
   obj->focus = g_strdup("");
   obj->blur = g_strdup("");
   return obj;
}

static void
object_destruct(Object_t *obj)
{
   if (obj->class->destruct)
      obj->class->destruct(obj);
   g_free(obj->url);
   g_free(obj->target);
   g_free(obj->comment);
   g_free(obj->mouse_over);
   g_free(obj->mouse_out);
   g_free(obj->focus);
   g_free(obj->blur);
   g_free(obj);
}

Object_t*
object_ref(Object_t *obj)
{
   obj->refcount++;
   return obj;
}

void
object_unref(Object_t *obj)
{
   if (!--obj->refcount)
      object_destruct(obj);
}

Object_t*
object_clone(Object_t *obj)
{
   Object_t *clone = obj->class->clone(obj);
   clone->class = obj->class;
   clone->refcount = 1;
   clone->selected = obj->selected;
   clone->locked = FALSE;
   clone->url = g_strdup(obj->url);
   clone->target = g_strdup(obj->target);
   clone->comment = g_strdup(obj->comment);
   clone->mouse_over = g_strdup(obj->mouse_over);
   clone->mouse_out = g_strdup(obj->mouse_out);
   clone->focus = g_strdup(obj->focus);
   clone->blur = g_strdup(obj->blur);
   return clone;
}

static Object_t*
object_copy(Object_t *src, Object_t *des)
{
   des->class = src->class;
   des->selected = src->selected;
   des->locked = FALSE;
   g_strreplace(&des->url, src->url);
   g_strreplace(&des->target, src->target);
   g_strreplace(&des->comment, src->comment);
   g_strreplace(&des->mouse_over, src->mouse_over);
   g_strreplace(&des->mouse_out, src->mouse_out);
   g_strreplace(&des->focus, src->focus);
   g_strreplace(&des->blur, src->blur);
   return des;
}

Object_t*
object_assign(Object_t *obj, Object_t *des)
{
   obj->class->assign(obj, des);
   return object_copy(obj, des);
}

void
object_draw(Object_t *obj, GdkWindow *window)
{
   PreferencesData_t *preferences = get_preferences();
   GdkGC *gc = (obj->selected) ? preferences->selected_gc
      : preferences->normal_gc;
   obj->class->draw(obj, window, gc);
   if (obj->selected && preferences->show_area_handle)
      obj->class->draw_sashes(obj, window, gc);
}

void
object_edit(Object_t *obj, gboolean add)
{
   if (!obj->class->info_dialog)
      obj->class->info_dialog = create_edit_area_info_dialog(obj);
   edit_area_info_dialog_show(obj->class->info_dialog, obj, add);
}

void
object_select(Object_t *obj)
{
   obj->selected = TRUE;
   object_list_callback_call(&obj->list->select_cb, obj);
   object_emit_geometry_signal(obj);
}

void
object_unselect(Object_t *obj)
{
   obj->selected = FALSE;
   object_list_callback_call(&obj->list->select_cb, obj);
   object_emit_geometry_signal(obj);
}

void
object_move(Object_t *obj, gint dx, gint dy)
{
   obj->class->move(obj, dx, dy);
   object_emit_geometry_signal(obj);
}

void
object_remove(Object_t *obj)
{
   object_list_remove(obj->list, obj);
   object_emit_geometry_signal(obj);
}

void
object_lock(Object_t *obj)
{
   obj->locked = TRUE;
}

void
object_unlock(Object_t *obj)
{
   obj->locked = FALSE;
}

void
object_set_url(Object_t *obj, const gchar *url)
{
   g_strreplace(&obj->url, url);
}

void
object_set_target(Object_t *obj, const gchar *target)
{
   g_strreplace(&obj->target, target);
}

void
object_set_comment(Object_t *obj, const gchar *comment)
{
   g_strreplace(&obj->comment, comment);
}

void
object_set_mouse_over(Object_t *obj, const gchar *mouse_over)
{
   g_strreplace(&obj->mouse_over, mouse_over);
}

void
object_set_mouse_out(Object_t *obj, const gchar *mouse_out)
{
   g_strreplace(&obj->mouse_out, mouse_out);
}

void
object_set_focus(Object_t *obj, const gchar *focus)
{
   g_strreplace(&obj->focus, focus);
}

void
object_set_blur(Object_t *obj, const gchar *blur)
{
   g_strreplace(&obj->blur, blur);
}

gint
object_get_position_in_list(Object_t *obj)
{
   return g_list_index(obj->list->list, (gpointer) obj);
}

void
object_emit_changed_signal(Object_t *obj)
{
   object_list_callback_call(&obj->list->changed_cb, obj);
}

void
object_emit_geometry_signal(Object_t *obj)
{
   object_list_callback_call(&obj->list->geometry_cb, obj);
}

void
object_emit_update_signal(Object_t *obj)
{
   object_list_callback_call(&obj->list->update_cb, obj);
}

void
do_object_locked_dialog(void)
{
   static DefaultDialog_t *dialog;
   if (!dialog) {
      dialog = make_default_dialog("Object locked");
      default_dialog_hide_cancel_button(dialog);
      default_dialog_hide_apply_button(dialog);
      default_dialog_set_label(
	 dialog,
	 "\n  You cannot delete the selected object  \n"
	 "since it is currently being edited.\n");
   }
   default_dialog_show(dialog);
}

Object_t*
object_factory_create_object(ObjectFactory_t *factory, gint x, gint y)
{
   return factory->obj = factory->create_object(x, y);
}

static gboolean
button_motion(GtkWidget *widget, GdkEventMotion *event,
	      ObjectFactory_t *factory)
{
   gint x = get_real_coord((gint) event->x);
   gint y = get_real_coord((gint) event->y);

   round_to_grid(&x, &y);

   object_draw(factory->obj, widget->window);
   factory->set_xy(factory->obj, event->state, x, y);
   object_draw(factory->obj, widget->window);

   return FALSE;
}

gboolean
object_on_button_press(GtkWidget *widget, GdkEventButton *event, gpointer data)
{
   static ObjectFactory_t *factory;
   PreferencesData_t *preferences = get_preferences();
   gint x = get_real_coord((gint) event->x);
   gint y = get_real_coord((gint) event->y);
   static Object_t *obj;

   if (event->type == GDK_2BUTTON_PRESS)
      return FALSE;
   round_to_grid(&x, &y);

   if (obj) {
      if (event->button == 1) {
	 if (!factory->finish || factory->finish(obj, x, y)) {
	    g_signal_handlers_disconnect_by_func(widget,
                                                 button_motion,
                                                 factory);
	    if (object_is_valid(obj)) {
	       Command_t *command = create_command_new(get_shapes(), obj);
	       command_execute(command);
	       if (preferences->prompt_for_area_info)
		  object_edit(obj, FALSE);
	    } else {
	       object_draw(obj, widget->window);
	       object_unref(obj);
	    }
	    gdk_gc_set_function(preferences->normal_gc, GDK_COPY);
	    obj = NULL;
	    main_clear_dimension();
	 }
      } else if (event->button == 3) {
	 object_draw(obj, widget->window);
	 if (!factory->cancel || factory->cancel(event, obj)) {
	    g_signal_handlers_disconnect_by_func(widget,
                                                 button_motion,
                                                 factory);
	    object_unref(obj);
	    gdk_gc_set_function(preferences->normal_gc, GDK_COPY);
	    obj = NULL;
	    main_clear_dimension();
	 } else {
	    object_draw(obj, widget->window);
	 }
      }
   } else {
      if (event->button == 1) {
	 factory = ((ObjectFactory_t*(*)(guint)) data)(event->state);
	 obj = object_factory_create_object(factory, x, y);
	
	 gdk_gc_set_function(preferences->normal_gc, GDK_XOR);

	 g_signal_connect(widget, "motion-notify-event",
                          G_CALLBACK(button_motion), factory);
      }
   }
   return FALSE;
}

ObjectList_t*
make_object_list(void)
{
  return g_new0 (ObjectList_t, 1);
}

void
object_list_destruct(ObjectList_t *list)
{
   object_list_remove_all(list);
   g_free(list->list);
}

ObjectList_t*
object_list_append_list(ObjectList_t *des, ObjectList_t *src)
{
   GList *p;
   for (p = src->list; p; p = p->next)
      object_list_append(des, object_clone((Object_t*) p->data));
   object_list_set_changed(des, (src) ? TRUE : FALSE);
   return des;
}

ObjectList_t*
object_list_copy(ObjectList_t *des, ObjectList_t *src)
{
   if (des)
      object_list_remove_all(des);
   else
      des = make_object_list();

   return object_list_append_list(des, src);
}

void
object_list_append(ObjectList_t *list, Object_t *object)
{
   object->list = list;
   list->list = g_list_append(list->list, (gpointer) object);
   object_list_set_changed(list, TRUE);
   object_list_callback_call(&list->add_cb, object);
}

void
object_list_prepend(ObjectList_t *list, Object_t *object)
{
   object->list = list;
   list->list = g_list_prepend(list->list, (gpointer) object);
   object_list_set_changed(list, TRUE);
   object_list_callback_call(&list->add_cb, object);
}

void
object_list_insert(ObjectList_t *list, gint position, Object_t *object)
{
   object->list = list;
   list->list = g_list_insert(list->list, (gpointer) object, position);
   object_list_set_changed(list, TRUE);
   object_list_callback_call(&list->add_cb, object);
}

void
object_list_remove(ObjectList_t *list, Object_t *object)
{
   list->list = g_list_remove(list->list, (gpointer) object);
   object_list_set_changed(list, TRUE);
   object_list_callback_call(&list->remove_cb, object);
   object_unref(object);
}

void
object_list_remove_link(ObjectList_t *list, GList *link)
{
   list->list = g_list_remove_link(list->list, link);
   object_list_set_changed(list, TRUE);
   object_list_callback_call(&list->remove_cb, (Object_t*) link->data);
}

void
object_list_update(ObjectList_t *list, Object_t *object)
{
   object_list_callback_call(&list->update_cb, object);
}

void
object_list_draw(ObjectList_t *list, GdkWindow *window)
{
   GList *p;
   for (p = list->list; p; p = p->next)
      object_draw((Object_t*) p->data, window);
}

void
object_list_draw_selected(ObjectList_t *list, GdkWindow *window)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected)
	 object_draw(obj, window);
   }
}

Object_t*
object_list_find(ObjectList_t *list, gint x, gint y)
{
   Object_t *found = NULL;
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->class->point_is_on(obj, x, y))
	 found = obj;
   }
   return found;
}

Object_t*
object_list_near_sash(ObjectList_t *list, gint x, gint y,
		      MoveSashFunc_t *sash_func)
{
   Object_t *found = NULL;
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected) {
	 MoveSashFunc_t func = obj->class->near_sash(obj, x, y);
	 if (func) {
	    found = obj;
	    *sash_func = func;
	 }
      }
   }
   return found;
}

void
object_list_remove_all(ObjectList_t *list)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      object_list_callback_call(&list->remove_cb, obj);
      object_unref(obj);
   }
   g_list_free(list->list);
   list->list = NULL;
   object_list_set_changed(list, TRUE);
}

void
clear_paste_buffer(void)
{
   if (_paste_buffer)
      object_list_remove_all(_paste_buffer);
   else
      _paste_buffer = make_object_list();
}

ObjectList_t*
get_paste_buffer(void)
{
   return _paste_buffer;
}

gint
object_list_cut(ObjectList_t *list)
{
   GList *p, *q;
   gint count = 0;

   clear_paste_buffer();
   for (p = list->list; p; p = q) {
      Object_t *obj = (Object_t*) p->data;
      q = p->next;
      if (obj->selected) {
	 if (obj->locked) {
	    do_object_locked_dialog();
	 } else {
	    object_list_append(_paste_buffer, obj);
	    object_list_remove_link(list, p);
	    count++;
	 }
      }
   }
   object_list_set_changed(list, (count) ? TRUE : FALSE);
   return count;
}

void
object_list_copy_to_paste_buffer(ObjectList_t *list)
{
   GList *p;

   clear_paste_buffer();
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected)
	 object_list_append(_paste_buffer, object_clone(obj));
   }
}

void
object_list_paste(ObjectList_t *list)
{
   object_list_append_list(list, _paste_buffer);
}

void
object_list_delete_selected(ObjectList_t *list)
{
   GList *p, *q;
   for (p = list->list; p; p = q) {
      Object_t *obj = (Object_t*) p->data;
      q = p->next;
      if (obj->selected) {
	 if (obj->locked) {
	    do_object_locked_dialog();
	 } else {
	    object_list_remove_link(list, p);
	    object_unref(obj);
	 }
      }
   }
}

void
object_list_edit_selected(ObjectList_t *list)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected) {
	 object_edit(obj, TRUE);
	 break;
      }
   }
}

gint
object_list_select_all(ObjectList_t *list)
{
   GList *p;
   gint count = 0;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (!obj->selected) {
	 object_select(obj);
	 count++;
      }
   }
   return count;
}

void
object_list_select_next(ObjectList_t *list)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected) {
	 object_unselect(obj);
	 p = (p->next) ? p->next : list->list;
	 object_select((Object_t*) p->data);
	 for (p = p->next; p; p = p->next) {
	    obj = (Object_t*) p->data;
	    if (obj->selected)
	       object_unselect(obj);
	 }
	 break;
      }
   }
}

void object_list_select_prev(ObjectList_t *list)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected) {
	 GList *q = (p->prev) ? p->prev : g_list_last(list->list);
	 for (; p; p = p->next) {
	    obj = (Object_t*) p->data;
	    if (obj->selected)
	       object_unselect(obj);
	 }
	 object_select((Object_t*) q->data);
	 break;
      }
   }
}

gint
object_list_select_region(ObjectList_t *list, gint x, gint y, gint width,
			  gint height)
{
   GList *p;
   gint count = 0;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      gint obj_x, obj_y, obj_width, obj_height;

      object_get_dimensions(obj, &obj_x, &obj_y, &obj_width, &obj_height);
      if (obj_x >= x && obj_x + obj_width <= x + width &&
	  obj_y >= y && obj_y + obj_height <= y + height) {
	 object_select(obj);
	 count++;
      }
   }
   return count;
}

gint
object_list_deselect_all(ObjectList_t *list, Object_t *exception)
{
   GList *p;
   gint count = 0;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected && obj != exception) {
	 object_unselect(obj);
	 count++;
      }
   }
   return count;
}

gint
object_list_nr_selected(ObjectList_t *list)
{
   GList *p;
   gint count = 0;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected)
	 count++;
   }
   return count;
}

void
object_list_resize(ObjectList_t *list, gint percentage_x, gint percentage_y)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      object_resize(obj, percentage_x, percentage_y);
   }
}

static void
object_list_swap_prev(ObjectList_t *list, GList *p)
{
   gpointer swap = p->data;
   p->data = p->prev->data;
   p->prev->data = swap;
   object_list_callback_call(&list->move_cb, (Object_t*) p->data);
   object_list_callback_call(&list->move_cb, (Object_t*) p->prev->data);
}

static void
object_list_swap_next(ObjectList_t *list, GList *p)
{
   gpointer swap = p->data;
   p->data = p->next->data;
   p->next->data = swap;
   object_list_callback_call(&list->move_cb, (Object_t*) p->data);
   object_list_callback_call(&list->move_cb, (Object_t*) p->next->data);
}

void
object_list_move_selected(ObjectList_t *list, gint dx, gint dy)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected)
	 object_move(obj, dx, dy);
   }
}

void
object_list_move_up(ObjectList_t *list, Object_t *obj)
{
   GList *p = g_list_find(list->list, (gpointer) obj);
   object_list_swap_prev(list, p);
}

void
object_list_move_down(ObjectList_t *list, Object_t *obj)
{
   GList *p = g_list_find(list->list, (gpointer) obj);
   object_list_swap_next(list, p);
}

void
object_list_move_selected_up(ObjectList_t *list)
{
   GList *p;

   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected && p->prev)
	 object_list_swap_prev(list, p);
   }
}

void
object_list_move_selected_down(ObjectList_t *list)
{
   GList *p;

   for (p = g_list_last(list->list); p; p = p->prev) {
      Object_t *obj = (Object_t*) p->data;
      if (obj->selected && p->next)
	 object_list_swap_next(list, p);
   }
}

void
object_list_move_to_front(ObjectList_t *list)
{
   GList *p, *q;
   guint length = g_list_length(list->list);

   for (p = list->list; length; p = q, length--) {
      Object_t *obj = (Object_t*) p->data;
      q = p->next;
      if (obj->selected) {
	 object_list_remove_link(list, p);
	 object_list_append(list, obj);
      }
   }
}

void
object_list_send_to_back(ObjectList_t *list)
{
   GList *p, *q;
   guint length = g_list_length(list->list);

   for (p = list->list; length; p = q, length--) {
      Object_t *obj = (Object_t*) p->data;
      q = p->next;
      if (obj->selected) {
	 object_list_remove_link(list, p);
	 object_list_prepend(list, obj);
      }
   }
}

static void
write_xml_attrib(const gchar *attrib, const gchar *value,
		 const gchar *default_text, gpointer param,
		 OutputFunc_t output)
{
   if (*value) {
      gchar *escaped_value = g_markup_escape_text(value, -1);
      output(param, " %s=\"%s\"", attrib, escaped_value);
      g_free(escaped_value);
   } else if (*default_text) {
      output(param, " %s", default_text);
   }
}

void
object_list_write_csim(ObjectList_t *list, gpointer param, OutputFunc_t output)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;

      output(param, "<area shape=");
      obj->class->write_csim(obj, param, output);

      write_xml_attrib("alt", obj->comment, "", param, output);
      write_xml_attrib("target", obj->target, "", param, output);
      write_xml_attrib("onmouseover", obj->mouse_over, "", param, output);
      write_xml_attrib("onmouseout", obj->mouse_out, "", param, output);
      write_xml_attrib("onfocus", obj->focus, "", param, output);
      write_xml_attrib("onblur", obj->blur, "", param, output);
      write_xml_attrib("href", obj->url, " nohref=\"nohref\"", param, output);
      output(param," />\n");
   }
}

void
object_list_write_cern(ObjectList_t *list, gpointer param, OutputFunc_t output)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;
      obj->class->write_cern(obj, param, output);
      output(param, " %s\n", obj->url);
   }
}

void
object_list_write_ncsa(ObjectList_t *list, gpointer param, OutputFunc_t output)
{
   GList *p;
   for (p = list->list; p; p = p->next) {
      Object_t *obj = (Object_t*) p->data;

      if (*obj->comment)
	 output(param, "# %s\n", obj->comment);
      obj->class->write_ncsa(obj, param, output);
      output(param, "\n");
   }
}

Related Patterns

• a


• b


• c