FilePresenter.java

package com.mucommander.ui.viewer;

import java.awt.Component;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.io.IOException;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenuBar;
import javax.swing.JScrollPane;

import com.mucommander.commons.file.AbstractFile;

/**
 * Abstract class that serves as a common base for the file presenter objects (FileViewer, FileEditor).
 * 
 * @author Arik Hadas
 */
public abstract class FilePresenter extends JScrollPane {
	
	/** FileFrame instance that contains this presenter (may be null). */
    private FileFrame frame;
    
    /** File currently being presented. */
    private AbstractFile file;
	
	public FilePresenter() {
		super(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
		
		addFocusListener(new FocusListener() {
			@Override
			public void focusLost(FocusEvent e) {}
			
			@Override
			public void focusGained(FocusEvent e) {
				// Delegate the focus to the JComponent that actually present the file
				Component component = FilePresenter.this.getViewport().getComponent(0);
				if (component != null)
					component.requestFocus();
			}
		});
	}
	
	/**
	 * Set component to be presented in the ScrollPane viewport
	 * 
	 * @param component the component to be presented
	 */
	protected void setComponentToPresent(JComponent component) {
		getViewport().removeAll();
		getViewport().add(component);
	}
	
	/**
     * Returns the frame which contains this presenter.
     * <p>
     * This method may return <code>null</code>if the presenter is not inside a FileFrame.
     * </p>
     * @return the frame which contains this presenter.
     * @see    #setFrame(FileFrame)
     */
    protected FileFrame getFrame() {
        return frame;
    }

    /**
     * Sets the FileFrame (separate window) that contains this FilePresenter.
     * @param frame frame that contains this <code>FilePresenter</code>.
     * @see         #getFrame()
     */
    void setFrame(FileFrame frame) {
        this.frame = frame;
    }
    
    /**
     * Returns a description of the file currently being presented which will be used as a window title.
     * This method returns the file's name but it can be overridden to provide more information.
     * @return this dialog's title.
     */
    protected String getTitle() {
        return file.getAbsolutePath();
    }

    /**
     * Returns the file that is being presented.
     *
     * @return the file that is being presented.
     */
    protected AbstractFile getCurrentFile() {
        return file;
    }

    /**
     * Sets the file that is to be presented.
     * This method will automatically be called after a file presenter is created and should not be called directly.
     * 
     * @param file file that is to be presented.
     */
    protected final void setCurrentFile(AbstractFile file) {
        this.file = file;
        // Update frame's title
        getFrame().setTitle(getTitle());
    }
	
	/**
	 * Open a given AbstraceFile for display.
	 * 
	 * @param file the file to be presented
	 * @throws IOException in case of an I/O problem
	 */
    public void open(AbstractFile file) throws IOException {
    	show(file);
    	setCurrentFile(file);
    }
    
    /**
     * Hook operation that can be override to make operations just before the presenter is disposed
     */
    public void beforeCloseHook() { }
	
	//////////////////////
    // Abstract methods //
    //////////////////////
	
    /**
     * This method is invoked when the specified file is about to be opened.
     * This method should retrieve the file and do the necessary so that this component can be displayed.
     *
     * @param  file        the file that is about to be viewed.
     * @throws IOException if an I/O error occurs.
     */
    protected abstract void show(AbstractFile file) throws IOException;
	
	/**
     * Returns the menu bar that controls the presenter's frame. The menu bar should be retrieved using this method and
     * not by calling {@link JFrame#getJMenuBar()}, which may return <code>null</code>.
     *
     * @return the menu bar that controls the presenter's frame.
     */
    protected abstract JMenuBar getMenuBar();
}