com.google.gwt.cell.client.ActionCell.java Source code

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Here is the source code for com.google.gwt.cell.client.ActionCell.java

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/*
 * Copyright 2010 Google Inc.
 *
 * 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 com.google.gwt.cell.client;

import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.EventTarget;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;

/**
 * A cell that renders a button and takes a delegate to perform actions on
 * mouseUp.
 *
 * @param <C> the type that this Cell represents
 */
public class ActionCell<C> extends AbstractCell<C> {

    /**
     * The delegate that will handle events from the cell.
     *
     * @param <T> the type that this delegate acts on
     */
    public static interface Delegate<T> {
        /**
         * Perform the desired action on the given object.
         *
         * @param object the object to be acted upon
         */
        void execute(T object);
    }

    private final SafeHtml html;
    private final Delegate<C> delegate;

    /**
     * Construct a new {@link ActionCell}.
     *
     * @param message the message to display on the button
     * @param delegate the delegate that will handle events
     */
    public ActionCell(SafeHtml message, Delegate<C> delegate) {
        super("click", "keydown");
        this.delegate = delegate;
        this.html = new SafeHtmlBuilder().appendHtmlConstant("<button type=\"button\" tabindex=\"-1\">")
                .append(message).appendHtmlConstant("</button>").toSafeHtml();
    }

    /**
     * Construct a new {@link ActionCell} with a text String that does not contain
     * HTML markup.
     *
     * @param text the text to display on the button
     * @param delegate the delegate that will handle events
     */
    public ActionCell(String text, Delegate<C> delegate) {
        this(SafeHtmlUtils.fromString(text), delegate);
    }

    @Override
    public void onBrowserEvent(Context context, Element parent, C value, NativeEvent event,
            ValueUpdater<C> valueUpdater) {
        super.onBrowserEvent(context, parent, value, event, valueUpdater);
        if ("click".equals(event.getType())) {
            EventTarget eventTarget = event.getEventTarget();
            if (!Element.is(eventTarget)) {
                return;
            }
            if (parent.getFirstChildElement().isOrHasChild(Element.as(eventTarget))) {
                // Ignore clicks that occur outside of the main element.
                onEnterKeyDown(context, parent, value, event, valueUpdater);
            }
        }
    }

    @Override
    public void render(Context context, C value, SafeHtmlBuilder sb) {
        sb.append(html);
    }

    @Override
    protected void onEnterKeyDown(Context context, Element parent, C value, NativeEvent event,
            ValueUpdater<C> valueUpdater) {
        delegate.execute(value);
    }
}