/* * Copyright (C) 2001-2004 Red Hat Inc. All Rights Reserved. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ package com.arsdigita.kernel; import com.arsdigita.persistence.OID; import com.arsdigita.persistence.metadata.ObjectType; import com.arsdigita.persistence.metadata.MetadataRoot; import com.arsdigita.persistence.SessionManager; import java.util.Map; import java.util.HashMap; import javax.servlet.http.HttpServletRequest; /** * Supports generically locating a domain object on the site. * The URLService can produce the path (relative to the root URL) to a page * that displays the domain object identified by a given OID. *

* The service works by delegating to a URLFinder based on the object * type of the given OID. * A URLFinder must be registered with the URLService for the object type * in question or one of its supertypes. That URLFinder dynamically produces a * URL path by a process that potentially involves a few database queries.

* *

* The URLService is only intended for single-object lookups. On pages that * display many objects (for example, a search results page), the URLs displayed * for each object should not be obtained from the URLService (for * performance reasons). Instead, a single "redirector page" should be the target * of all those links. The user clicks on a link, which then uses the * URLService to find the object's URL and redirect the user to the resulting * URL. An example of this process is:

*
    *
  1. User searches for objects based on keywords.
    2. *
  2. Search page displays matching objects, with a link for each * object. The targets of these links are all the same: * .../display-result?id=:id&object_type=:object_type
    3. *
  3. User clicks on one of those links.
    4. *
  4. Display-result page uses the URLService to find the specified * object's URL and redirect the user there.
    5. *
* * The GenericURLFinder class provides a simple URLFinder that can be * registered for many object types. * * @see GenericURLFinder * * @author Oumi Mehrotra * @version $Id: URLService.java 287 2005-02-22 00:29:02Z sskracic $ **/ public class URLService { private static Map s_finders = new HashMap(); /** * Returns a URL path to a page that displays the object identified by * the given oid. The URL path is relative to the server root. * The URL is obtained by delgating to the registered or * inherited URLFinder for the given oid's object type. * * @throws URLFinderNotFoundException when there is no URLFinder * registered for the given oid's object type nor any of its * supertypes. * * @throws NoValidURLException when the * URLFinder registered for the given oid's object type is unable * to produce a valid non-null URL. **/ public static String locate(OID oid) throws URLFinderNotFoundException, NoValidURLException { return locate(oid,null); } /** * Returns a URL path to a page that displays the object identified by * the given oid. The URL path is relative to the server root. * The URL is obtained by delgating to the registered or * inherited URLFinder for the given oid's object type. * * @throws URLFinderNotFoundException when there is no URLFinder * registered for the given oid's object type nor any of its * supertypes. * * @throws NoValidURLException when the * URLFinder registered for the given oid's object type is unable * to produce a valid non-null URL. **/ public static String locate(OID oid, String context) throws URLFinderNotFoundException, NoValidURLException { URLFinder f = getFinder(oid.getObjectType()); if (f==null) { throw new URLFinderNotFoundException("There is no URLFinder " + "registered for " + "data object type " + oid.getObjectType().getQualifiedName()); } String url = (context == null) ? f.find(oid) : f.find(oid,context); if (url == null) { throw new NoValidURLException("The URLFinder for " + oid.getObjectType().getQualifiedName() + "produced a null URL for " + oid); } return url; } /** * Registers a URLFinder for the specified data object type. * The registered finder will be * used by the locate method for OIDs whose type is equal to * the specified type. That is, * when locate(x) is executed, the specified * finder will be used if the specified * dataObjectType is equal to x.getObjectType(). * *

* Any object type that does not have a finder registered * with this service is not supported by this service. * *

* If another finder was already registered for the specified * object type, the previous finder is replaced and returned. * * @param objectType the data object type for which to register * the specified finder * * @param finder the URLFinder that will handle data objects * of the specified data object type when the * locate method is called * * @return the previous finder that was * registered with this service for this object type. **/ public synchronized static URLFinder registerFinder(ObjectType objectType, URLFinder finder) { return (URLFinder) s_finders.put(objectType, finder); } /** * Wrapper around registerFinder(ObjectType, URLFinder). * * @see #registerFinder(ObjectType, URLFinder) **/ public synchronized static URLFinder registerFinder(String objectType, URLFinder finder) { MetadataRoot meta = SessionManager.getMetadataRoot(); return (URLFinder) s_finders.put(meta.getObjectType(objectType), finder); } /** * Returns the URLFinder registered for the given object type. **/ public synchronized static URLFinder getRegisteredFinder(ObjectType objectType) { return (URLFinder) s_finders.get(objectType); } /** * * Returns the URLFinder registered for the given object type. * **/ public synchronized static URLFinder getRegisteredFinder(String objectType) { MetadataRoot meta = SessionManager.getMetadataRoot(); return (URLFinder) s_finders.get(meta.getObjectType(objectType)); } /** * Gets the registered or inherited URLFinder for the specified object type. * This is the URLFinder that is registered * for the specified object type or its closest supertype that has * a registered URLFinder. Returns null if there is no supertype that * has a registered URLFinder. * * @param objectType the object type whose registered or inherited * URLFinder is to be returned * * @return the registered or inherited URLFinder for the given object type. * Returns null if no finder is registered for the * given type or any of its supertypes. **/ public synchronized static URLFinder getFinder(ObjectType objectType) { ObjectType type = objectType; while (type!=null && !s_finders.containsKey(type)) { type = type.getSupertype(); } return (URLFinder) s_finders.get(type); } /** * * @see #getFinder(ObjectType) **/ public synchronized static URLFinder getFinder(String objectType) { MetadataRoot meta = SessionManager.getMetadataRoot(); return (URLFinder) s_finders.get(meta.getObjectType(objectType)); } public static OID getNonencodedOID(HttpServletRequest sreq) { if (sreq == null) { return null; } String query = sreq.getQueryString(); if (query == null) { return null; } int start = query.indexOf(OID_START); if (start == -1) { return null; } start = start+OID_START.length(); int end = query.indexOf(OID_END); if (end == -1) { end = query.length(); } return OID.valueOf(query.substring(start, end)); } public static final String OID_START = "oid="; public static final String OID_END = "&"; }