com.github.peholmst.mvp4vaadin.ui.ViewDisplayNameLabel.java Source code

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Here is the source code for com.github.peholmst.mvp4vaadin.ui.ViewDisplayNameLabel.java

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/*
 * Copyright (c) 2011 Petter Holmstrm
 *
 * 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.github.peholmst.mvp4vaadin.ui;

import com.github.peholmst.mvp4vaadin.View;
import com.github.peholmst.mvp4vaadin.ViewEvent;
import com.github.peholmst.mvp4vaadin.ViewListener;
import com.github.peholmst.mvp4vaadin.events.DisplayNameChangedViewEvent;
import com.vaadin.ui.Label;

/**
 * A label that contains the display name of a certain view. When the display
 * name changes, the label is automatically updated.
 * 
 * @author Petter Holmstrm
 * @since 1.0
 */
@SuppressWarnings("unchecked")
public class ViewDisplayNameLabel extends Label implements ViewListener {

    private static final long serialVersionUID = -664243311290214350L;

    private View view;

    /**
     * Creates a new <code>ViewDisplayNameLabel</code> without a view.
     */
    public ViewDisplayNameLabel() {
    }

    /**
     * Creates a new <code>ViewDisplayNameLabel</code> with the specified view.
     */
    public ViewDisplayNameLabel(View view) {
        setView(view);
    }

    /**
     * Returns the view whose display name is shown in this label, or
     * <code>null</code> if none has been set.
     */
    public View getView() {
        return view;
    }

    /**
     * Sets the view whose display name should be shown in this label, may be
     * <code>null</code>.
     */
    public void setView(View view) {
        if (this.view != null) {
            this.view.removeListener(this);
        }
        this.view = view;
        updateLabelValue();
        if (this.view != null) {
            this.view.addListener(this);
        }
    }

    @Override
    public void handleViewEvent(ViewEvent event) {
        if (event.getSource() == view && event instanceof DisplayNameChangedViewEvent) {
            updateLabelValue();
        }
    }

    private void updateLabelValue() {
        if (view == null) {
            setValue("");
        } else {
            setValue(view.getDisplayName());
        }
    }

}