propertymanager.java

JSP聊天系统

package org.ehotsoft.yekki.util;

import java.util.*;
import java.io.*;

public class PropertyManager {

    private static PropertyManager manager = null;
    private static Object managerLock = new Object();
    private static String propsName = "/yekki.properties";

    public static String getProperty( String name ) {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }
        return manager.getProp( name );
    }

	public static void setProperty( String name, String value ) {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }

        manager.setProp( name, value );
    }

	public static void deleteProperty( String name ) {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }
        manager.deleteProp( name );
    }

    public static Enumeration propertyNames() {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }
        return manager.propNames();
    }

	public static boolean propertyFileIsReadable() {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }

        return manager.propFileIsReadable();
    }

    public static boolean propertyFileIsWritable() {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }

        return manager.propFileIsWritable();
    }

    public static boolean propertyFileExists() {

        if ( manager == null ) {

            synchronized( managerLock ) {

                if ( manager == null ) {

                    manager = new PropertyManager( propsName );
                }
            }
        }
        return manager.propFileExists();
    }


    private Properties properties = null;
    private Object propertiesLock = new Object();
    private String resourceURI;

    private PropertyManager( String resourceURI ) {
    
		this.resourceURI = resourceURI;
    }
	
	protected String getProp( String name ) {
        
		if ( properties == null ) {

            synchronized( propertiesLock ) {
                //Need an additional check
                if ( properties == null ) {

                    loadProps();
                }
            }
        }

        String property = properties.getProperty( name );

        if ( property == null ) {

            return null;
        }
        else {

            return property.trim();
        }
    }

    protected void setProp( String name, String value ) {

        synchronized ( propertiesLock ) {

            if ( properties == null ) {

                loadProps();
            }

            properties.setProperty( name, value );
            saveProps();
        }
    }

    protected void deleteProp( String name ) {
		
		synchronized ( propertiesLock ) {
        
			if ( properties == null ) {
                loadProps();
            }
            properties.remove( name );
            saveProps();
        }
    }

    protected Enumeration propNames() {

        if ( properties == null ) {

            synchronized( propertiesLock ) {
                //Need an additional check
                if ( properties == null ) {
                    loadProps();
                }
            }
        }

        return properties.propertyNames();
    }

    private void loadProps() {

        properties = new Properties();
        InputStream in = null;

        try {

            in = getClass().getResourceAsStream( resourceURI );
            properties.load( in );
        }
        catch ( Exception e ) {

            System.err.println( "Error reading yekki properties in PropertyManager.loadProps() " + e );
            e.printStackTrace();
        }
        finally {

            try {

                in.close();
            } catch ( Exception e ) { }
        }
    }

    private void saveProps() {
        //Now, save the properties to disk. In order for this to work, the user
        //needs to have set the path field in the properties file. Trim
        //the String to make sure there are no extra spaces.
        String path = properties.getProperty( "path" ).trim();
        OutputStream out = null;

        try {

            out = new FileOutputStream( path );
            properties.store( out, "yekki.properties -- " + ( new java.util.Date() ) );
        }
        catch ( Exception ioe ) {

            System.err.println( "There was an error writing jive.properties to " + path + ". " +
                "Ensure that the path exists and that the Jive process has permission " +
                "to write to it -- " + ioe );
            ioe.printStackTrace();
        }
        finally {

            try {
               out.close();
            }
			catch ( Exception e ) {
			
			}
        }
    }

	public boolean propFileIsReadable() {

        try {

            InputStream in = getClass().getResourceAsStream( resourceURI );
            return true;
        }
        catch ( Exception e ) {

            return false;
        }
    }

    public boolean propFileExists() {

        String path = getProp( "path" );

        if(  path == null  ) {

            return false;
        }
        File file = new File( path );

        if ( file.isFile() ) {

            return true;
        }
        else {

            return false;
        }
    }

    public boolean propFileIsWritable() {

        String path = getProp( "path" );
        File file = new File( path );

        if ( file.isFile() ) {

            if ( file.canWrite() ) {

                return true;
            }
            else {

                return false;
            }
        }
        else {

            return false;
        }
    }
}