001// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.model;
016
017import org.apache.tapestry5.annotations.MixinAfter;
018import org.apache.tapestry5.annotations.Persist;
019import org.apache.tapestry5.annotations.SupportsInformalParameters;
020import org.apache.tapestry5.ioc.Resource;
021import org.slf4j.Logger;
022
023import java.util.List;
024import java.util.Set;
025
026/**
027 * Defines a component in terms of its capabilities, parameters, sub-components, etc. During <em>runtime</em>, the
028 * component model is immutable. During <em>construction</em> time, when the class is being transformed and loaded, the
029 * model is mutable.
030 *
031 * @see org.apache.tapestry5.model.MutableComponentModel
032 */
033public interface ComponentModel
034{
035    /**
036     * Returns the name of the library that defines this component; this may be the empty string for
037     * an application page or component, or will be a name of a library (possibly including "core" for built-in
038     * components).
039     * Library names are defined by the {@link org.apache.tapestry5.services.LibraryMapping} contributions
040     * to the {@link org.apache.tapestry5.services.ComponentClassResolver} service.
041     *
042     * @return library name containing the component, or empty string for application components
043     * @since 5.4
044     */
045    String getLibraryName();
046
047    /**
048     * Is this a model of a page (rather than a component, mixin, or base-class)?
049     *
050     * @return true if a page
051     * @since 5.3
052     */
053    boolean isPage();
054
055    /**
056     * Returns the resource corresponding to the class file for this component. This is used to find related resources,
057     * such as the component's template and message catalog.
058     */
059    Resource getBaseResource();
060
061    /**
062     * The fully qualified class name of the component.
063     */
064    String getComponentClassName();
065
066    /**
067     * Returns the ids of all embedded components defined within the component class (via the {@link
068     * org.apache.tapestry5.annotations.Component} annotation), including those defined by any super-class.
069     */
070    List<String> getEmbeddedComponentIds();
071
072    /**
073     * Returns an embedded component defined by this component or by a super-class.
074     *
075     * @param componentId
076     *         the id of the embedded component
077     * @return the embedded component model, or null if no component exists with that id
078     */
079    EmbeddedComponentModel getEmbeddedComponentModel(String componentId);
080
081    /**
082     * Returns the persistent strategy associated with the field.
083     *
084     * @param fieldName
085     * @return the corresponding strategy, or the empty string
086     * @throws IllegalArgumentException
087     *         if the named field is not marked as persistent
088     */
089    String getFieldPersistenceStrategy(String fieldName);
090
091    /**
092     * Returns object that will be used to log warnings and errors related to this component.
093     *
094     * @see org.apache.tapestry5.annotations.Log
095     */
096    Logger getLogger();
097
098    /**
099     * Returns a list of the class names of mixins that are part of the component's implementation.
100     */
101    List<String> getMixinClassNames();
102
103    /**
104     * Return a single parameter model by parameter name, or null if the parameter is not defined (is not
105     * a formal parameter). This may be a parameter defined by this component, or from a base class.
106     *
107     * @param parameterName
108     *         the name of the parameter (case is ignored)
109     * @return the parameter model if found in this model or a parent model, or null if not found
110     */
111    ParameterModel getParameterModel(String parameterName);
112
113    /**
114     * Returns true if the named parameter is formally defined (there's a ParameterModel).
115     *
116     * @param parameterName
117     *         name of the parameter (case is ignored)
118     * @since 5.2.0
119     */
120    boolean isFormalParameter(String parameterName);
121
122    /**
123     * Returns an alphabetically sorted list of the names of all formal parameters. This includes parameters defined by
124     * a base class.
125     */
126
127    List<String> getParameterNames();
128
129    /**
130     * Returns an alphabetically sorted list of the names of all formal parameters defined by this specific class
131     * (parameters inherited from base classes are not identified).
132     */
133    List<String> getDeclaredParameterNames();
134
135    /**
136     * Returns a list of the names of all persistent fields (within this class, or any super-class). The names are
137     * sorted alphabetically.
138     *
139     * @see Persist
140     */
141    List<String> getPersistentFieldNames();
142
143    /**
144     * Returns true if the modeled component is a root class, a component class whose parent class is not a component
145     * class.  We may in the future require that components only extend from Object.
146     *
147     * @return true if a root class, false if a subclass
148     */
149    boolean isRootClass();
150
151    /**
152     * Returns true if the model indicates that informal parameters, additional parameters beyond the formal parameter
153     * defined for the component, are supported. This is false in most cases, but may be set to true for specific
154     * classes (when the {@link SupportsInformalParameters} annotation is present, or inherited from a super-class).
155     *
156     * @return true if this component model supports informal parameters
157     */
158    boolean getSupportsInformalParameters();
159
160    /**
161     * Returns the component model for this component's super-class, if it exists. Remember that only classes in the
162     * correct packages, are considered component classes.
163     *
164     * @return the parent class model, or null if this component's super class is not itself a component class
165     */
166    ComponentModel getParentModel();
167
168    /**
169     * Relevant for component mixins only. Indicates that the mixin behavior should occur <em>after</em> (not before)
170     * the component. Normally, this flag is set by the presence of the {@link MixinAfter} annotation.
171     *
172     * @return true if the mixin should operate after, not before, the component
173     */
174    boolean isMixinAfter();
175
176    /**
177     * Gets a meta value identified by the given key. If the current model does not provide a value for the key, then
178     * the parent component model (if any) is searched.
179     *
180     * @param key
181     *         identifies the value to be accessed
182     * @return the value for the key (possibly inherited from a parent model), or null
183     */
184    String getMeta(String key);
185
186    /**
187     * Returns a set of all the render phases that this model (including parent models) that are handled. Render phases
188     * are represented by the corresponding annotation ({@link org.apache.tapestry5.annotations.BeginRender}, {@link
189     * org.apache.tapestry5.annotations.AfterRender}, etc.).
190     *
191     * @return set of classes
192     * @since 5.0.19, 5.1.0.0
193     */
194    Set<Class> getHandledRenderPhases();
195
196    /**
197     * Determines if the component has an event handler for the indicated event name (case insensitive). This includes
198     * handlers in the component class itself, or its super-classes, but does not include event handlers supplied by
199     * implementation or instance mixins.
200     *
201     * @param eventType
202     *         name of event to check (case insensitive)
203     * @return true if event handler present
204     */
205    boolean handlesEvent(String eventType);
206
207    /**
208     * @param mixinClassName
209     *         class name of the mixin for which the ordering is desired
210     * @return the ordering constraint(s) for the mixin, potentially null.
211     * @since 5.2.0
212     */
213    String[] getOrderForMixin(String mixinClassName);
214
215    /**
216     * Relevant for pages only, indicates that the component handle the {@link org.apache.tapestry5.EventConstants.ACTIVATE}
217     * events with a catch all rules
218     *
219     * @since 5.4
220     * @see {@link MutableComponentModel.doHandleActivationEventContext()}
221     * @return <code>true</code> in case the page implement a catch all rules for the activate event context,
222     * <code>false</code> otherwise
223     */
224    boolean handleActivationEventContext();
225}