001    // Copyright 2004, 2005 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    
015    package org.apache.tapestry.components;
016    
017    import org.apache.tapestry.IComponent;
018    import org.apache.tapestry.IMarkupWriter;
019    import org.apache.tapestry.IRequestCycle;
020    import org.apache.tapestry.engine.ILink;
021    
022    /**
023     * A component that renders an HTML <a> element. It exposes some properties to the components
024     * it wraps. This is basically to facilitate the {@link org.apache.tapestry.html.Rollover}
025     * component.
026     * 
027     * @author Howard Lewis Ship
028     */
029    
030    public interface ILinkComponent extends IComponent
031    {
032    
033        /**
034         * Returns the desired scheme (i.e., "http" or "https") for the link, or null to not output a
035         * specific scheme (in which case the URL will fall under the incoming request's scheme).
036         * 
037         * @since 4.0
038         */
039    
040        public String getScheme();
041    
042        /**
043         * Returns whether this service link component is enabled or disabled.
044         * 
045         * @since 0.2.9
046         */
047    
048        public boolean isDisabled();
049    
050        /**
051         * Returns the anchor defined for this link, or null for no anchor.
052         * 
053         * @since 3.0
054         */
055    
056        public String getAnchor();
057    
058        /**
059         * Returns the name of the target window or frame for this link, or null if current window or
060         * frame is to be used.
061         * 
062         * @since 4.0
063         */
064        public String getTarget();
065    
066        /**
067         * Adds a new event handler. When the event occurs, the JavaScript function specified is
068         * executed. Multiple functions can be specified, in which case all of them are executed.
069         * <p>
070         * This was created for use by {@link org.apache.tapestry.html.Rollover} to set mouse over and
071         * mouse out handlers on the {@link ILinkComponent} that wraps it, but can be used for many
072         * other things as well.
073         * 
074         * @since 0.2.9
075         */
076    
077        public void addEventHandler(LinkEventType type, String functionName);
078    
079        /**
080         * Invoked by the {@link org.apache.tapestry.link.ILinkRenderer} (if the link is not disabled)
081         * to provide a {@link org.apache.tapestry.engine.EngineServiceLink} that the renderer can
082         * convert into a URL.
083         */
084    
085        public ILink getLink(IRequestCycle cycle);
086    
087        /**
088         * Invoked (by the {@link org.apache.tapestry.link.ILinkRenderer}) to make the link render any
089         * additional attributes. These are informal parameters, plus any attributes related to events.
090         * This is only invoked for non-disabled links.
091         * 
092         * @since 3.0
093         */
094    
095        public void renderAdditionalAttributes(IMarkupWriter writer, IRequestCycle cycle);
096    }