AbstractPageParametersLink.java

/**
 * Licensed 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.brixcms.web.nodepage;

import org.apache.wicket.Component;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.link.AbstractLink;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;

/**
 * Base class that knows how to recursively collect parameters from child nodes
 * that implement {@link PageParametersAware}. Child nodes contribute parameters
 * that they need for future instantiation, allowing a stateful URL to be
 * composed from the dynamic closure of the page and it's tiles.
 *
 * @author Igor Vaynberg
 */
public abstract class AbstractPageParametersLink extends AbstractLink {
    public AbstractPageParametersLink(String id) {
        super(id);
    }

    public AbstractPageParametersLink(String id, IModel<?> model) {
        super(id, model);
    }

    @Override
    protected void onComponentTag(ComponentTag tag) {
        super.onComponentTag(tag);

        // If we're disabled
        if (!isEnabledInHierarchy()) {
            disableLink(tag);
        } else {
            String url = buildUrl();

            if (tag.getName().equalsIgnoreCase("a") || tag.getName().equalsIgnoreCase("link") || tag.getName().equalsIgnoreCase("area")) {
                // generate the href attribute
                tag.put("href", url);
            } else {
                // or generate an onclick JS handler directly
                // in firefox when the element is quickly clicked 3 times a
                // second request is
                // generated during page load. This check ensures that the click
                // is ignored
                tag.put("onclick", "var win = this.ownerDocument.defaultView || this.ownerDocument.parentWindow; "
                        + "if (win == window) { window.location.href='" + url + "'; } ;return false");
            }
        }
    }

    protected String buildUrl() {
        final BrixPageParameters parameters = new BrixPageParameters(getInitialParameters());
        getPage().visitChildren(PageParametersAware.class, new IVisitor<Component, PageParametersAware>() {
            @Override
            public void component(Component component, IVisit<PageParametersAware> pageParametersAwareIVisit) {
                ((PageParametersAware) component).contributeToPageParameters(parameters);
            }
        });
        contributeToPageParameters(parameters);
        return constructUrl(parameters);
    }

    /**
     * Returns the initial {@link BrixPageParameters} used to build the URL.
     *
     * @return
     */
    protected BrixPageParameters getInitialParameters() {
        return new BrixPageParameters();
    }

    /**
     * Allows to change {@link BrixPageParameters} after all other components
     * have contributed their state to it. This method can be used to
     * postprocess the link URL.
     */
    protected void contributeToPageParameters(BrixPageParameters parameters) {

    }

    protected abstract String constructUrl(BrixPageParameters params);
}