一个连接池的例子（来自JIVE）（6）

//文件：PropertyManager.java
//这个类其实没什么用了，可以去掉，但需要去掉前面几个类中对这个类的引用。
package com.qingtuo.db.pool;
import java.util.*;
import java.io.*;
/**
* Manages properties for the entire Jive system. Properties are merely
* pieces of information that need to be saved in between server restarts.
*

* At the moment, properties are stored in a Java Properties file. In a version
* of Jive coming soon, the properties file format will move to XML. XML
* properties will allow hierarchical property structures which may mean the
* API of this class will have to change.
*

* Jive properties are only meant to be set and retrevied by core Jive classes.
* Therefore, skin writers should probably ignore this class.
*

* This class is implemented as a singleton since many classloaders seem to
* take issue with doing classpath resource loading from a static context.
*/
public class PropertyManager {
    private static PropertyManager manager = null;
    private static Object managerLock = new Object();
    private static String propsName = "/pcc_2000.properties";
    /**
     * Returns a Jive property
     *
     * @param name the name of the property to return.
     * @returns the property value specified by name.
     */
    public static String getProperty(String name) {
        if (manager == null) {
            synchronized(managerLock) {
                if (manager == null) {