com.google.gwt.gen2.demo.scrolltable.client.option.AbstractOption.java Source code

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Here is the source code for com.google.gwt.gen2.demo.scrolltable.client.option.AbstractOption.java

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/*
 * Copyright 2008 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.gen2.demo.scrolltable.client.option;

import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HasHorizontalAlignment;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * An option that can be lazily initialized.
 */
public abstract class AbstractOption extends Composite {
    /**
     * The style name applied to cells that contain labels.
     */
    protected static final String STYLENAME_LABEL = "AbstractOption-Label";

    /**
     * The panel that wraps the contents.
     */
    private VerticalPanel wrapper = new VerticalPanel();

    /**
     * Indicates if we've initialized this option or not.
     */
    private boolean initialized = false;

    /**
     * Construct a new {@link AbstractOption}.
     */
    public AbstractOption() {
        initWidget(wrapper);
    }

    /**
     * @return the description to display at the top of the option
     */
    protected abstract String getDescription();

    /**
     * Initialize the tab for the first time.
     */
    protected void initialize() {
        if (initialized) {
            return;
        }
        initialized = true;

        // Add the content
        wrapper.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);
        wrapper.add(new HTML(getDescription()));
        wrapper.add(onInitialize());
    }

    /**
     * Render the option.
     * 
     * @return the widget to initialize to.
     */
    protected abstract Widget onInitialize();

    /**
     * This method is called immediately after a widget becomes attached to the
     * browser's document.
     */
    @Override
    protected void onLoad() {
        super.onLoad();
        initialize();
    }
}