001: package org.apache.turbine.modules.pages;
002:
003: /*
004: * Licensed to the Apache Software Foundation (ASF) under one
005: * or more contributor license agreements. See the NOTICE file
006: * distributed with this work for additional information
007: * regarding copyright ownership. The ASF licenses this file
008: * to you under the Apache License, Version 2.0 (the
009: * "License"); you may not use this file except in compliance
010: * with the License. You may obtain a copy of the License at
011: *
012: * http://www.apache.org/licenses/LICENSE-2.0
013: *
014: * Unless required by applicable law or agreed to in writing,
015: * software distributed under the License is distributed on an
016: * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017: * KIND, either express or implied. See the License for the
018: * specific language governing permissions and limitations
019: * under the License.
020: */
021:
022: import org.apache.turbine.services.template.TurbineTemplate;
023: import org.apache.turbine.util.RunData;
024: import org.apache.turbine.util.TurbineException;
025:
026: /**
027: * When building sites using templates, Screens need only be defined
028: * for templates which require dynamic (database or object) data.
029: *
030: * <p>
031: *
032: * This page can be used on sites where the number of Screens can be
033: * much less than the number of templates. The templates can be
034: * grouped in directories with common layouts. Screen modules are
035: * then expected to be placed in packages corresponding with the
036: * templates' directories and follow a specific naming scheme.
037: *
038: * <p>
039: *
040: * The template parameter is parsed and and a Screen whose package
041: * matches the templates path and shares the same name minus any
042: * extension and beginning with a capital letter is searched for. If
043: * not found, a Screen in a package matching the template's path with
044: * name Default is searched for. If still not found, a Screen with
045: * name Default is looked for in packages corresponding to parent
046: * directories in the template's path until a match is found.
047: *
048: * <p>
049: *
050: * For example if data.getParameters().getString("template") returns
051: * /about_us/directions/driving.wm, the search follows
052: * about_us.directions.Driving, about_us.directions.Default,
053: * about_us.Default, Default, WebMacroSiteScreen (i.e. the default
054: * screen set in TurbineResources).
055: *
056: * <p>
057: *
058: * Only one Layout module is used, since it is expected that any
059: * dynamic content will be placed in navigations and screens. The
060: * layout template to be used is found in a similar way to the Screen.
061: * For example the following paths will be searched in the layouts
062: * subdirectory: /about_us/directions/driving.wm,
063: * /about_us/directions/default.wm, /about_us/default.wm, /default.wm,
064: * where wm is the value of the template.default.extension property.
065: *
066: * <p>
067: *
068: * This approach allows a site with largely static content to be
069: * updated and added to regularly by those with little Java
070: * experience.
071: *
072: * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
073: * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
074: * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
075: * @version $Id: TemplatePage.java 534527 2007-05-02 16:10:59Z tv $
076: */
077: public class TemplatePage extends DefaultPage {
078: /**
079: * Works with TemplateService to set up default templates and
080: * corresponding class modules.
081: *
082: * @param data Turbine information.
083: * @exception Exception, a generic exception.
084: */
085: protected void doBuildAfterAction(RunData data) throws Exception {
086: // The Template Service at this point must fetch the Screen class
087: // to match a given template. If the Screen class has already been
088: // set by an action, skip this, because the user has the already
089: // specified the Screen class he wants to use.
090: if (!data.hasScreen()) {
091: // This is effectively getting the "template" parameter
092: // from the parameter parser in rundata. This is coming
093: // from the request for a template.
094: String template = data.getTemplateInfo()
095: .getScreenTemplate();
096:
097: // Get the layout template and the correct Screen.
098: String layoutTemplate = TurbineTemplate
099: .getLayoutTemplateName(template);
100: data.getTemplateInfo().setLayoutTemplate(layoutTemplate);
101:
102: String screen = TurbineTemplate.getScreenName(template);
103:
104: if (screen == null) {
105: String errMsg = "Couldn't map Template " + template
106: + " to any Screen class!";
107: log.error(errMsg);
108: throw new TurbineException(errMsg);
109: }
110: data.setScreen(screen);
111: }
112: }
113: }
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