PersistentBlackboardPlugIn.java

package com.vividsolutions.jump.workbench.ui.plugin;

import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;

import com.vividsolutions.jump.util.Blackboard;
import com.vividsolutions.jump.util.java2xml.Java2XML;
import com.vividsolutions.jump.util.java2xml.XML2Java;
import com.vividsolutions.jump.workbench.WorkbenchContext;
import com.vividsolutions.jump.workbench.plugin.AbstractPlugIn;
import com.vividsolutions.jump.workbench.plugin.PlugInContext;

public class PersistentBlackboardPlugIn extends AbstractPlugIn {
    private static String persistenceDirectory = ".";

    private static String fileName = "workbench-state.xml";

    private static final String BLACKBOARD_KEY = PersistentBlackboardPlugIn.class
            .getName()
            + " - BLACKBOARD";

    public static Blackboard get(WorkbenchContext context) {
        Blackboard blackboard = context.getBlackboard();
        return get(blackboard);
    }

    public static Blackboard get(Blackboard blackboard) {
        if (blackboard.get(BLACKBOARD_KEY) == null) {
            blackboard.put(BLACKBOARD_KEY, new Blackboard());
        }
        return (Blackboard) blackboard.get(BLACKBOARD_KEY);
    }

    public static void setPersistenceDirectory(String value) {
        persistenceDirectory = value;
    }

    public static void setFileName(String value) {
        fileName = value;
    }

    public String getFilePath() {
        return persistenceDirectory + "/" + fileName;
    }

    public void initialize(final PlugInContext context) throws Exception {
        restoreState(context.getWorkbenchContext());
        context.getWorkbenchFrame().addComponentListener(
                new ComponentAdapter() {
                    public void componentHidden(ComponentEvent e) {
                        saveState(context.getWorkbenchContext());
                    }
                });
    }

    private void restoreState(WorkbenchContext workbenchContext) {
        if (!new File(getFilePath()).exists()) { return; }
        try {
            FileReader fileReader = new FileReader(getFilePath());

            try {
                BufferedReader bufferedReader = new BufferedReader(fileReader);

                try {
                    get(workbenchContext).putAll(
                            ((Blackboard) new XML2Java(workbenchContext
                                    .getWorkbench().getPlugInManager()
                                    .getClassLoader()).read(bufferedReader,
                                    Blackboard.class)).getProperties());
                } finally {
                    bufferedReader.close();
                }
            } finally {
                fileReader.close();
            }
        } catch (Exception e) {
            // Before we just ate exceptions. But this is confusing when
            // there is a problem and we don't know that the cause is an
            // exception [Jon Aquino 2005-03-11]
            e.printStackTrace(System.err);
        }
    }

    private void saveState(WorkbenchContext workbenchContext) {
        try {
            FileWriter fileWriter = new FileWriter(getFilePath(), false);

            try {
                BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);

                try {
                    new Java2XML().write(get(workbenchContext),
                            "workbench-state", bufferedWriter);
                    bufferedWriter.flush();
                    fileWriter.flush();
                } finally {
                    bufferedWriter.close();
                }
            } finally {
                fileWriter.close();
            }
        } catch (Exception e) {
            e.printStackTrace(System.err);
            //Eat it. Persistence isn't critical. [Jon Aquino]
        }
    }

}