tapestry-framework/src/java/org/apache/tapestry/internal/Component.java

package org.apache.tapestry.internal;

import org.apache.tapestry.IRender;

/**
 * Represents the <em>internal</em> component api exposed for use by core framework code only.
 *
 * <p>
 * Use at your own risk as everything in this API is subject to change without notice from release to
 * release.
 * </p>
 */
public interface Component {

    /**
     * Returns the list of of {@link IRender} elements contained by this component. Ie whatever
     * has been added via {@link org.apache.tapestry.IComponent#addBody(IRender)}.
     *
     * @return The values, if any. Null otherwise.
     */
    IRender[] getContainedRenderers();

    /**
     * In some rare cases a component has both outer and inner renderers - such as with {@link org.apache.tapestry.BaseComponent}. This
     * value should return the normal inner renderers most components do in those instances while the other
     * {@link #getContainedRenderers()} should return the outer renderers.
     * 
     * @return The inner renderers if this component supports more than one type, null otherwise.
     */
    IRender[] getInnerRenderers();

    /**
     * Checks if this component has been targeted / connected to for client side
     * event listening via @EventListener.
     *
     * @return True if anything has targeted this component, false otherwise.
     */
    boolean hasEvents();

    /**
     * Sets whether or not this component has events.
     *
     * @param hasEvents Whether or not this component has connected events.
     */
    void setHasEvents(boolean hasEvents);
}