org.apache.wicket.ajax.markup.html.form.AjaxFallbackButton.java Source code

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Here is the source code for org.apache.wicket.ajax.markup.html.form.AjaxFallbackButton.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.ajax.markup.html.form;

import java.util.Optional;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.attributes.AjaxRequestAttributes;
import org.apache.wicket.ajax.form.AjaxFormSubmitBehavior;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.form.Button;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.model.IModel;

/**
 * An ajax submit button that will degrade to a normal request if ajax is not available or
 * javascript is disabled.
 * 
 * @since 1.3
 * 
 * @author Jeremy Thomerson (jthomerson)
 * @author Alastair Maw
 * 
 * 
 */
public abstract class AjaxFallbackButton extends Button {
    private static final long serialVersionUID = 1L;

    private final Form<?> mForm;

    /**
     * Construct.
     * 
     * @param id
     * @param form
     */
    public AjaxFallbackButton(String id, Form<?> form) {
        this(id, null, form);
    }

    /**
     * Construct.
     * 
     * @param id
     * @param model
     * @param form
     */
    public AjaxFallbackButton(String id, IModel<String> model, Form<?> form) {
        super(id, model);
        mForm = form;

        add(newAjaxEventBehavior(form, "click"));
    }

    protected AjaxFormSubmitBehavior newAjaxEventBehavior(Form<?> form, String event) {
        return new AjaxFormSubmitBehavior(form, event) {
            private static final long serialVersionUID = 1L;

            @Override
            protected void onSubmit(AjaxRequestTarget target) {
                AjaxFallbackButton.this.onSubmit(Optional.of(target));
            }

            @Override
            protected void onAfterSubmit(AjaxRequestTarget target) {
                AjaxFallbackButton.this.onAfterSubmit(Optional.of(target));
            }

            @Override
            protected void onError(AjaxRequestTarget target) {
                AjaxFallbackButton.this.onError(Optional.of(target));
            }

            @Override
            public boolean getDefaultProcessing() {
                return AjaxFallbackButton.this.getDefaultFormProcessing();
            }

            @Override
            protected void updateAjaxAttributes(AjaxRequestAttributes attributes) {
                super.updateAjaxAttributes(attributes);

                // do not allow normal form submit to happen
                attributes.setPreventDefault(true);

                AjaxFallbackButton.this.updateAjaxAttributes(attributes);
            }

            @Override
            public boolean getStatelessHint(Component component) {
                return AjaxFallbackButton.this.getStatelessHint();
            }
        };
    }

    protected void updateAjaxAttributes(AjaxRequestAttributes attributes) {
    }

    /**
     * Listener method invoked on form submit with errors. If ajax failed and this event was
     * generated via a normal submission, the target argument will be null.
     * 
     * @param target
     */
    protected void onError(Optional<AjaxRequestTarget> target) {
    }

    @Override
    public final void onError() {
        if (getRequestCycle().find(AjaxRequestTarget.class).isPresent() == false) {
            onError(Optional.empty());
        }
    }

    @Override
    public final void onSubmit() {
        if (getRequestCycle().find(AjaxRequestTarget.class).isPresent() == false) {
            onSubmit(Optional.empty());
        }
    }

    @Override
    public final void onAfterSubmit() {
        if (getRequestCycle().find(AjaxRequestTarget.class).isPresent() == false) {
            onAfterSubmit(Optional.empty());
        }
    }

    @Override
    public Form<?> getForm() {
        return mForm == null ? super.getForm() : mForm;
    }

    /**
     * Callback for the onClick event. If ajax failed and this event was generated via a normal
     * submission, the target argument will be {@link Optional#empty()}. This method will be called
     * <em>before</em> {@link Form#onSubmit()}.
     * 
     * @param target
     *            ajax target if this linked was invoked using ajax, {@link Optional#empty()}
     *            otherwise
     */
    protected void onSubmit(final Optional<AjaxRequestTarget> target) {
    }

    /**
     * Callback for the onClick event. If ajax failed and this event was generated via a normal
     * submission, the target argument will be null. This method will be called <em>after</em>
     * {@link Form#onSubmit()}.
     * 
     * @param target
     *            ajax target if this linked was invoked using ajax, null otherwise
     */
    protected void onAfterSubmit(final Optional<AjaxRequestTarget> target) {
    }

    /**
     * Helper methods that both checks whether the link is enabled and whether the action ENABLE is
     * allowed.
     * 
     * @return whether the link should be rendered as enabled
     */
    protected final boolean isButtonEnabled() {
        return isEnabledInHierarchy();
    }

    @Override
    protected void onComponentTag(ComponentTag tag) {
        String tagName = tag.getName();
        if (!("input".equalsIgnoreCase(tagName) || "button".equalsIgnoreCase(tagName))) {
            String msg = String.format(
                    "%s must be used only with <input type=\"submit\"> or <input type=\"submit\"> markup elements. "
                            + "The fallback functionality doesn't work for other markup elements. "
                            + "Component path: %s, markup element: <%s>.",
                    AjaxFallbackButton.class.getSimpleName(), getClassRelativePath(), tagName);
            findMarkupStream().throwMarkupException(msg);
        }

        super.onComponentTag(tag);
    }
}