enhproperties.java

用Java写的面相对象的数据库管理系统

// You can redistribute this software and/or modify it under the terms of
// the Ozone Library License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-2000 by SMB GmbH. All rights reserved.
//
// $Id: EnhProperties.java,v 1.4 2000/10/28 16:55:21 daniela Exp $

package org.ozoneDB.util;

import java.io.*;
import java.util.*;
import org.ozoneDB.DxLib.*;
import org.ozoneDB.core.Env;


/**
 * EnhProperties has methods to store/update the value of a property to handle
 * such dynamic properties.
 * <p>
 * In addition the Properties EnhProperties can hold not only String properties
 * but most of other primitive types and raw objects. Non-string properties are
 * internaly stored as Strings.
 * <p>
 * Setup extends java.util.Properties. So the system properties can be used as
 * defaults.
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.4 $Date: 2000/10/28 16:55:21 $
 */
public class EnhProperties extends Properties {
    
    /**
     * An Observable object that is responsible for this properties. Directly
     * extending the class is not possible because it already extends Properties.
     */
    protected EnhObservable observable;
    
    
    public EnhProperties() {
        observable = new EnhObservable();
    }
    
    
    public EnhProperties( Properties _defaults ) {
        super( _defaults );
        observable = new EnhObservable();
    }
    
    
    public void addObserver( Observer _observer ) {
        observable.addObserver( _observer );
    } 
    
    
    public void removeObserver( Observer _observer ) {
        observable.deleteObserver( _observer );
    } 
    
    
    public void notifyObservers() {
        observable.notifyObservers( this );
    } 
    
    
    public boolean hasChanged() {
        return observable.hasChanged();
    } 
    
    
    /**
     * @param properties
     * @param keyPrefix
     */
    public void addProperties( Properties properties, String keyPrefix ) {
        observable.setChanged();
        for (Enumeration e = properties.keys(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            if (key.startsWith( keyPrefix )) {
                // System.out.println (key);
                String val = properties.getProperty( key, "" );
                setStringProperty( key, val );
            } 
        } 
    } 
    
    
    /**
     * @param _val
     * @param _key
     */
    public synchronized void setStringProperty( String _key, String _val ) {
        observable.setChanged();
        super.put( _key, _val );
    } 
    
    
    /**
     * @param _key
     * @param _default The default value to use if no property is found.
     */
    public String stringProperty( String _key, String _default ) {
        return super.getProperty( _key, _default );
    } 
    
    
    /**
     * @param _key
     * @param _default The default value to use if no property is found.
     */
    public DxCollection stringsProperty( String _key, String _default ) {
        String propList = stringProperty( _key, _default );
        DxArrayBag result = new DxArrayBag();
        
        StringTokenizer st = new StringTokenizer( propList, " \t,", false );
        while (st.hasMoreTokens()) {
            String token = st.nextToken();
            // System.out.println ("'" + token + "'");
            result.add( token );
        } 
        return result;
    } 
    
    
    /**
     * @param _val
     * @param _key
     */
    public void setProperty( String _key, Object _val ) {
        observable.setChanged();
        try {
            ByteArrayOutputStream buf = new ByteArrayOutputStream( 1024 );
            ObjectOutputStream out = new ObjectOutputStream( buf );
            out.writeObject( _val );
            out.close();
            
            MimeBase64Encoder encoder = new MimeBase64Encoder();
            encoder.translate( buf.toByteArray() );
            
            setStringProperty( _key, new String( encoder.getCharArray() ) );
        } catch (Exception e) {
            throw new RuntimeException( e.getMessage() );
        } 
    } 
    
    
    /**
     * @param _key
     * @param _default The default value to use if no property is found.
     */
    public Object property( String _key, Object _default ) {
        try {
            String result = stringProperty( _key, (String)_default );
            if (result != null) {
                MimeBase64Decoder decoder = new MimeBase64Decoder();
                decoder.translate( result.toCharArray() );
                
                ObjectInputStream in = new ObjectInputStream( new ByteArrayInputStream( decoder.getByteArray() ) );
                return in.readObject();
            } else {
                return null;
            } 
        } catch (Exception e) {
            throw new RuntimeException( e.getMessage() );
        } 
    } 
    
    
    /**
     * @param _val
     * @param _key
     */
    public void setIntProperty( String _key, int _val ) {
        setStringProperty( _key, String.valueOf( _val ) );
    } 
    
    
    /**
     * @param _key
     * @param _default The default value to use if no property is found.
     */
    public int intProperty( String _key, int _default ) {
        String result = stringProperty( _key, String.valueOf( _default ) );
        return Integer.parseInt( result );
    } 
    
    
    /**
     * @param _key
     * @param _default The default value to use if no property is found.
     */
    public long longProperty( String _key, long _default ) {
        String result = stringProperty( _key, String.valueOf( _default ) );
        return Long.valueOf( result ).longValue();
    } 
    
    
    /**
     * @param _key
     * @param _default The default value to use if no property is found.
     */
    public boolean booleanProperty( String _key, boolean _default ) {
        String result = stringProperty( _key, String.valueOf( _default ) );
        return Boolean.valueOf( result ).booleanValue();
    } 
    
    
    /**
     * @param _val
     * @param _key
     */
    public void setLongProperty( String _key, long _val ) {
        setStringProperty( _key, String.valueOf( _val ) );
    } 
    
    
    /**
     * @param _val
     * @param _key
     */
    public void setBooleanProperty( String _key, boolean _val ) {
        setStringProperty( _key, String.valueOf( _val ) );
    } 
    
    
    /**
     * @param
     * @param keyPrefix
     * @param printPrefix
     */
    public void print( PrintStream out, String keyPrefix, String printPrefix ) {
        DxTreeSet sortedProps = new DxTreeSet( new DxStringComparator() );
        for (Enumeration e = propertyNames(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            String val = stringProperty( key, "(not set)" );
            //avoid printing "object" properties
            //currently not supported!!!
            if (key.startsWith( keyPrefix ) && !val.startsWith( "[object]" )) {
                sortedProps.add( printPrefix + key + " = " + val );
            } 
        } 
        for (DxIterator it = sortedProps.iterator(); it.next() != null;) {
            out.println( it.object().toString() );
        } 
    } 
    
}


/**
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.4 $Date: 2000/10/28 16:55:21 $
 */
class EnhObservable extends Observable {
    
    
    public EnhObservable() {
        super();
    }
    
    
    public void setChanged() {
        super.setChanged();
    } 
    
}