src/main/java/com/google/gerrit/client/ui/LazyTabChild.java

// Copyright (C) 2008 The Android Open Source Project
//
// 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.gerrit.client.ui;

import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.Widget;

/** Panel for use within a TabPanel to create the widget only on selection. */
public abstract class LazyTabChild<T extends Widget> extends SimplePanel {
  /** @return the widget to display in this panel. */
  protected abstract T create();

  @Override
  public void setVisible(final boolean visible) {
    if (visible && getWidget() == null) {
      setWidget(create());
    }
    super.setVisible(visible);
  }
}