org.apache.wicket.protocol.http.AjaxEnclosureListener.java Source code

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Here is the source code for org.apache.wicket.protocol.http.AjaxEnclosureListener.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.wicket.protocol.http;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.markup.html.internal.Enclosure;
import org.apache.wicket.markup.html.internal.InlineEnclosure;
import org.apache.wicket.markup.parser.filter.InlineEnclosureHandler;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;

/**
 * This listener adds Enclosures to AjaxTarget, where the child controller of the said Enclosure is
 * already added. This is a part of the fix to the problem:
 * 
 * "Changing the visibility of a child component in Ajax callback method will not affect the entire
 * enclosure but just the child component itself. This is because only the child component is added
 * to the AjaxRequestTarget"
 * 
 * When used with an "Inline" Enclosure, this problem is fixed.
 * 
 * Syntax for inline enclosure:
 * 
 * <tr wicket:enclosure="controllingChildId">
 * 
 * In this example the tag used is tr, but any other tag could be used as well. The attribute
 * "wicket:enclosure" is mandatory, and is used to recognise an inline enclosure. The value of the
 * attribute, here "controllingChildId" can contain an id for the child (controller) element. If the
 * said value is not given, the first element inside the enclosure will be used as a controller
 * child. If there are no elements inside the enclosure, the parsing will fail.
 * 
 * 
 * @see WebApplication
 * @see InlineEnclosure
 * @see InlineEnclosureHandler
 *
 * @author Joonas Hamalainen
 */
public class AjaxEnclosureListener implements AjaxRequestTarget.IListener {
    /**
     * Construct.
     */
    public AjaxEnclosureListener() {
    }

    /**
     * Try to find Enclosures that have their controllers added already, and add them to the target.
     */
    @Override
    public void onBeforeRespond(final Map<String, Component> map, final AjaxRequestTarget target) {
        final List<String> keysToRemove = new ArrayList<>();

        target.getPage().visitChildren(InlineEnclosure.class, new IVisitor<InlineEnclosure, Void>() {
            @Override
            public void component(final InlineEnclosure enclosure, final IVisit<Void> visit) {
                Iterator<Map.Entry<String, Component>> entriesItor = map.entrySet().iterator();
                while (entriesItor.hasNext()) {
                    Map.Entry<String, Component> entry = entriesItor.next();
                    Component component = entry.getValue();
                    if (isControllerOfEnclosure(component, enclosure)) {
                        final Component controller = component;
                        target.add(enclosure);
                        visit.dontGoDeeper();
                        enclosure.visitChildren(new IVisitor<Component, Void>() {
                            @Override
                            public void component(Component descendant, IVisit<Void> visit) {
                                if (descendant == controller) {
                                    // if the controlling component is in the enclosure we do not need to repaint it
                                    // individually, it will be repainted as part of the enclosure repaint
                                    keysToRemove.add(controller.getId());
                                }
                            }
                        });
                        break;
                    }
                }
            }
        });

        for (String key : keysToRemove) {
            map.remove(key);
        }
    }

    /**
     * Check if a given component is the controlling child of a given enclosure
     * 
     * @param component
     * @param enclosure
     * @return true if the given component is the controlling child of the given InlineEnclosure
     */
    public static boolean isControllerOfEnclosure(final Component component, final Enclosure enclosure) {
        return (enclosure.get(enclosure.getChildId()) == component || // #queue()
                enclosure.getParent().get(enclosure.getChildId()) == component); // #add()
    }
}