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/*
 * Copyright © 1996-2009 GlobalMentor, 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.globalmentor.swing;

import java.awt.FlowLayout;
import java.awt.LayoutManager;
import java.io.IOException;

import com.globalmentor.model.Model;
import com.globalmentor.model.ModelView;

/**
 * Panel that provides one or more views to a data model.
 * 
 * Bound properties:
 * 
 * 
 * {@link Model#MODEL_PROPERTY} ({@link Model})
 * Indicates the data model has been changed.
 * 
 * @author Garret Wilson
 */
public class ModelPanel extends ModifiablePanel implements ModelView {

	/** The data model for which this component provides a view. */
	private M model;

	/**
	 * Returns the component data model.
	 * 
	 * A calling program should first call verify() to ensure the data is valid and that the model reflects the currently entered data.
	 * @return The data model for which this component provides a view.
	 * @see #verify()
	 */
	public M getModel() {
		return model;
	}

	/**
	 * Sets the data model. This is a bound property.
	 * @param newModel The data model for which this component provides a view.
	 */
	public void setModel(final M newModel) {
		final M oldModel = model; //get the old value
		if(oldModel != newModel) { //if the value is really changing
			model = newModel; //update the value
			try {
				loadModel(); //try to load the model, as we've changed models
				setModified(false); //show that we are no longer modified
			} catch(IOException ioException) { //if there were any problems saving the model
				AbstractSwingApplication.displayApplicationError(this, ioException); //display the error
			}
			//show that the property has changed
			firePropertyChange(Model.MODEL_PROPERTY, oldModel, newModel);
		}
	}

	/**
	 * Model constructor.
	 * @param model The data model for which this component provides a view.
	 */
	public ModelPanel(final M model) {
		this(model, true); //initialize the panel
	}

	/**
	 * Constructor with optional initialization that uses a FlowLayout.
	 * @param model The data model for which this component provides a view.
	 * @param initialize true if the panel should initialize itself by calling the initialization methods.
	 * @see #FlowLayout
	 */
	public ModelPanel(final M model, final boolean initialize) {
		this(new FlowLayout(), model, initialize); //construct the panel with a flow layout by default
	}

	/**
	 * Layout constructor.
	 * @param layout The layout manager to use.
	 * @param model The data model for which this component provides a view.
	 */
	public ModelPanel(final LayoutManager layout, final M model) {
		this(layout, model, true); //construct the class with the layout, initializing the panel
	}

	/**
	 * Layout constructor with optional initialization.
	 * @param layout The layout manager to use.
	 * @param model The data model for which this component provides a view.
	 * @param initialize true if the panel should initialize itself by calling the initialization methods.
	 */
	public ModelPanel(final LayoutManager layout, final M model, final boolean initialize) {
		super(layout, false); //construct the parent but don't initialize the panel
		this.model = model; //save the model
		if(initialize) //if we should initialize
			initialize(); //initialize the panel
	}

	/**
	 * Initializes the data.
	 * 

	 * This version sets the data view to the default.
	 * 
	 */
	protected void initializeData() {
		super.initializeData(); //do the default initialization
		try {
			loadModel(); //try to load the model, since we're just now initializing
		} catch(IOException ioException) { //if there were any problems saving the model
			AbstractSwingApplication.displayApplicationError(this, ioException); //display the error
		}
	}

	/**
	 * Loads the data from the model to the view, if necessary.
	 * @throws IOException Thrown if there was an error loading the model.
	 */
	public void loadModel() throws IOException {
	}

	/**
	 * Stores the current data being edited to the model, if necessary.
	 * @throws IOException Thrown if there was an error saving the model.
	 */
	public void saveModel() throws IOException {
	}

	/**
	 * Verifies the component.
	 * 
	 * This version saves any editing changes to the model.
	 * 
	 * @return true if the component contents are valid, false if not.
	 * @see #saveModel()
	 */
	public boolean verify() {
		boolean verified = super.verify(); //perform the default verification---do this first so that any child components that we may need for our model can be verified, saving their models
		if(verified) { //if the default verification succeeded
			try {
				saveModel(); //store any model data that was being edited, if any
			} catch(IOException ioException) { //if there were any problems saving the model
				AbstractSwingApplication.displayApplicationError(this, ioException); //display the error
				verified = false; //show that the component didn't verify
			}
		}
		return verified; //show whether or not we successfully verified the component
	}

}