    001// Licensed under the Apache License, Version 2.0 (the "License");
    002// you may not use this file except in compliance with the License.
    003// You may obtain a copy of the License at
    004//
    005// http://www.apache.org/licenses/LICENSE-2.0
    006//
    007// Unless required by applicable law or agreed to in writing, software
    008// distributed under the License is distributed on an "AS IS" BASIS,
    009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    010// See the License for the specific language governing permissions and
    011// limitations under the License.
    012
    013package org.apache.tapestry5;
    014
    015import org.apache.tapestry5.ioc.Locatable;
    016import org.apache.tapestry5.services.pageload.ComponentResourceSelector;
    017import org.slf4j.Logger;
    018
    019import java.util.Locale;
    020
    021/**
    022 * Operations shared by the public {@link org.apache.tapestry5.ComponentResources} interface and
    023 * {@link org.apache.tapestry5.internal.structure.ComponentPageElement} interface (on the internal side).
    024 */
    025@SuppressWarnings(
    026{ "JavaDoc" })
    027public interface ComponentResourcesCommon extends Locatable
    028{
    029    /**
    030     * Returns the simple (or local) id of the component. The id will be unique within the component's immediate
    031     * container. For a page's root component, the value null is returned.
    032     */
    033    String getId();
    034
    035    /**
    036     * Return a string consisting the concatenated ids of all containing components, separated by periods. In addition,
    037     * nested ids are always all lower case. I.e., "foo.bar.baz". Returns null for the root component of a page.
    038     */
    039    String getNestedId();
    040
    041    /**
    042     * Returns a string consisting of the logical name of the containing page, and the {@link #getNestedId() nested id}
    043     * of this component, separated by a colon. I.e., "MyPage:foo.bar.baz". For a page, returns just the page's name.
    044     *
    045     * This value is often used to obtain an equivalent component instance in a later request.
    046     *
    047     * @see org.apache.tapestry5.services.ComponentSource#getComponent(String)
    048     */
    049    String getCompleteId();
    050
    051    /**
    052     * A convenience method for invoking {@link #triggerContextEvent(String, EventContext , ComponentEventCallback)}. Wraps
    053     * the context values into an {@link org.apache.tapestry5.EventContext}.
    054     *
    055     * @param eventType
    056     *            event type (as determined from the request, or otherwise by design)
    057     * @param contextValues
    058     *            Values that may be provided to the event handler method as method parameters, or null if no
    059     *            context values are available
    060     * @param callback
    061     *            the handler to be informed of the result, or null if the event is a notification that does
    062     *            not support return values from event handler methods (the value true is allowed even if the
    063     *            handler is null).
    064     * @return true if any event handler was invoked (even if no event handler method returns a non-null value)
    065     * @throws org.apache.tapestry5.runtime.ComponentEventException
    066     *             if an event handler method throws a checked or unchecked exception
    067     * @see org.apache.tapestry5.internal.transform.OnEventWorker
    068     * @see org.apache.tapestry5.annotations.OnEvent
    069     */
    070    boolean triggerEvent(String eventType, Object[] contextValues, ComponentEventCallback callback);
    071
    072    /**
    073     * Triggers a component event. A search for an event handling method will occur, first in the component, then its
    074     * container, and so on. When a matching event handler method is located, it is invoked. If the method returns a
    075     * value, the value is passed to the callback (if callback is null, then it is an error for a method to return a
    076     * non-null value).
    077     *
    078     * Resolution of event type to event handler methods is case insensitive.
    079     *
    080     * @param eventType
    081     *            event type (as determined from the request, or otherwise by design)
    082     * @param context
    083     *            the context (as extracted from the request, or provided by the triggering component); these
    084     *            values may be provided to event handler methods via their parameters (may not be null)
    085     * @param callback
    086     *            the handler to be informed of the result, or null if the event is a notification that does not
    087     *            support return values from event handler methods (the value true is allowed even if the handler
    088     *            is null).
    089     * @return true if any event handler was invoked (even if no event handler method returns a non-null value)
    090     * @throws org.apache.tapestry5.runtime.ComponentEventException
    091     *             if an event handler method throws a checked or unchecked exception
    092     * @see org.apache.tapestry5.internal.transform.OnEventWorker
    093     * @see org.apache.tapestry5.annotations.OnEvent
    094     */
    095    boolean triggerContextEvent(String eventType, EventContext context, ComponentEventCallback callback);
    096
    097    /**
    098     * Returns true if the component is currently rendering, false otherwise. This is most often used to determine if
    099     * parameter values should be cached.
    100     */
    101    boolean isRendering();
    102
    103    /**
    104     * Returns the log instance associated with the component (which is based on the component or mixin's class name).
    105     *
    106     * @see org.apache.tapestry5.model.ComponentModel#getLogger()
    107     */
    108    Logger getLogger();
    109
    110    /**
    111     * Returns the locale for the page containing this component.
    112     *
    113     * @see #getResourceSelector()
    114     */
    115    Locale getLocale();
    116
    117    /**
    118     * Returns the selector used when constructing the component and its containing page.
    119     *
    120     * @since 5.3
    121     */
    122    ComponentResourceSelector getResourceSelector();
    123
    124    /**
    125     * Returns the name of element that represents the component in its template, or the provided default element name
    126     * if the element was a component type (in the Tapestry namespace).
    127     *
    128     * @param defaultElementName
    129     *            element name to return if the element name is not known (may be null)
    130     * @return the element name
    131     */
    132    String getElementName(String defaultElementName);
    133
    134    /**
    135     * Returns a block from the component's template, referenced by its id.
    136     *
    137     * @param blockId
    138     *            the id of the block (case insensitive)
    139     * @return the identified Block
    140     * @throws BlockNotFoundException
    141     *             if no block with the given id exists
    142     * @see #findBlock(String)
    143     */
    144    Block getBlock(String blockId);
    145
    146    /**
    147     * As with {@link #getBlock(String)}, but returns null if the block is not found.
    148     *
    149     * @param blockId
    150     *            the id of the block (case insensitive)
    151     * @return the block, or null
    152     */
    153    Block findBlock(String blockId);
    154
    155    /**
    156     * Returns the <em>logical</em> name of the page containing this component. This is the short name (it often appears
    157     * in URLs)
    158     *
    159     * @return the logical name of the page which contains this component
    160     */
    161    String getPageName();
    162
    163    /**
    164     * Returns true if the element has a body and false otherwise. Only components may have a body; pages and mixins
    165     * will return false.
    166     */
    167    boolean hasBody();
    168
    169    /**
    170     * Returns the body of this component as a (possibly empty) block. When invoked on a mixin, returns the containing
    171     * component's body.
    172     */
    173    Block getBody();
    174
    175    /**
    176     * Creates a component event request link as a callback for this component. The event type and context (as well as
    177     * the page name and nested component id) will be encoded into a URL. A request for the URL will
    178     * {@linkplain #triggerEvent(String, Object[], org.apache.tapestry5.ComponentEventCallback)} trigger} the named
    179     * event on the
    180     * component.
    181     *
    182     * @param eventType
    183     *            the type of event to be triggered. Event types should be Java identifiers (contain only
    184     *            letters, numbers and the underscore).
    185     * @param context
    186     *            additional objects to be encoded into the path portion of the link; each is converted to a
    187     *            string and URI encoded
    188     * @return link object for the callback
    189     */
    190    Link createEventLink(String eventType, Object... context);
    191
    192    /**
    193     * Creates a component event request link as a callback for this component. The event type and context (as well as
    194     * the page name and nested component id) will be encoded into a URL. A request for the URL will
    195     * {@linkplain #triggerEvent(String, Object[], org.apache.tapestry5.ComponentEventCallback)} trigger} the named
    196     * event on the
    197     * component. This is only used for form submission events, as extra data may be encoded in the form as hidden
    198     * fields.
    199     *
    200     * @param eventType
    201     *            the type of event to be triggered. Event types should be Java identifiers (contain only
    202     *            letters, numbers and the underscore).
    203     * @param context
    204     *            additional objects to be encoded into the path portion of the link; each is converted to a
    205     *            string and URI encoded
    206     * @return link object for the callback
    207     */
    208    Link createFormEventLink(String eventType, Object... context);
    209}