Tutorial: Viewer Plugin

Maybe that can give you a starting point. This will implement a TextViewer as Plugin.

First:get the source-package

Simple type

ant newplugin -Dplugin.name=textviewer

. This will generate a sub-directory "plugins/other/textviewer". If you use Eclipse type:

ant eclipse-project

this will generate the project-files for Eclipse and you can import Hawron (Import Project). Your new Plugin-folder should be on the right place now.

Next: create a MyTextViewerPlugin.java in the src-folder and paste the code below

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

//the hawron interfaces
import de.miethxml.hawron.gui.context.viewer.CacheableViewer;
import de.miethxml.hawron.gui.context.viewer.ViewerCloseListener;


public class MyTextViewerPlugin implements CacheableViewer {
	private JFrame frame;
	private JTextArea textarea;
	//the ViewerCloselisteners
	private ArrayList listeners = new ArrayList();
	
	/**
	 * the parameter empty constructor is used always
	 */
	public MyTextViewerPlugin() {
		super();		
	}

	
	public void addViewerCloseListener(ViewerCloseListener listener) {
		listeners.add(listener);
	}

	
	public void removeViewerCloseListener(ViewerCloseListener listener) {
		listeners.remove(listeners);
	}

	public void dispose() {
            //we do nothing here     
	}

	
	public void destroy() {
	        frame.dispose();
	        frame= null; 
	}

	
	public void init() {
		frame = new JFrame("MyTextViewerPlugin");
		frame.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				//we do this for caching
				frame.setVisible(false);
				fireCloseEvent();
			}
		});

		textarea = new JTextArea();
		//only viewing
		textarea.setEditable(false);
		JScrollPane scrollpane = new JScrollPane(textarea);
		frame.getContentPane().add(scrollpane, BorderLayout.CENTER);
		frame.setSize(new Dimension(640, 480));
	}


	public void setVisible(boolean state) {
		frame.setVisible(state);
	}


	public void open(String file) {
		//we get now the file and put the content to the textarea.
		//delete the old content
		textarea.setText("");
		
		try {
			BufferedReader in = new BufferedReader( new FileReader(file));
			String line=null;
			while(( line = in.readLine()) != null){
				textarea.append(line+"\n");
			}
			in.close();
			
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}catch (IOException ioe){
			ioe.printStackTrace();
		}
	}

	
	public boolean isSupported(String file) {
		//we will support text-files
		if (file.toLowerCase().endsWith(".txt")) {
			return true;
		}
		//we will support log-files too
		if (file.toLowerCase().endsWith(".log")) {
			return true;
		}
		return false;	
	}


	public Icon getIcon() {
		//if we have a icon we place it in the jar-file later 
                //otherwise we get a button without a icon
		URL imageurl = this.getClass().getResource("icon.gif");
		ImageIcon icon = new ImageIcon(imageurl);
		return icon;
	}


	public String getToolTip(String lang) {
		return "MyTextViewer";
	}

	
	public Viewer createNewViewer() {
		MyTextViewerPlugin viewer = new MyTextViewerPlugin();
	    viewer.init();
	    return viewer;		
	}
	
	private void fireCloseEvent() {
		//avoid problems by removing the listeners
		Iterator i = ((List)listeners.clone()).iterator();
		while (i.hasNext()) {
			ViewerCloseListener listener = (ViewerCloseListener)i.next();
			listener.close(this);
		}
	}

}
    

Write the plugin-descriptor (edit the auto-generated file in the plugin-directory)

<?xml version="1.0"  ?>
<plugin>
   <name>My plugin</name>
    <instanceclass>MyTextViewerPlugin</instanceclass>
    <interface>de.miethxml.hawron.gui.context.viewer.Viewer</interface>
    <description>My plugin</description>
    <resources>
        <classpath src="textviewer.jar"/>
    </resources>
</plugin>
   

Build now

Open a project and view log- or textfiles with your plugin now. You can see if you select a file, which is not supported by your plugin, it will disabled

Maybe you will now write a extended logfileviewer, please contrib it.