jboss源码中片段分析

package com.test;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.List;
import java.util.ListIterator;
//有兴趣可以自己执行玩耍
public class Test_pkgsString {
	static final String[] systemPackages;
	static final String[] systemPaths;
	static {
		// final String pkgsString = AccessController.doPrivileged(new
		// PropertyReadAction("jboss.modules.system.pkgs"));
		final String pkgsString = "org.javaRasp,org.apache,javax.servlet";
		final List<String> list = new ArrayList<String>();
		if (pkgsString != null) {
			int i;
			int nc = -1;
			do {
				i = nc + 1;
				nc = pkgsString.indexOf(',', i);
				String part;
				if (nc == -1) {
					part = pkgsString.substring(i).trim();
				} else {
					part = pkgsString.substring(i, nc).trim();
				}
				if (part.length() > 0) {
					list.add((part + ".").intern());
				}
			} while (nc != -1);
		}
		systemPackages = list.toArray(list.toArray(new String[list.size()]));
		final ListIterator<String> iterator = list.listIterator();
		// http://youtrack.jetbrains.net/issue/IDEA-72097
		// noinspection WhileLoopReplaceableByForEach
		while (iterator.hasNext()) {
			iterator.set(iterator.next().replace('.', '/'));
		}
		systemPaths = list.toArray(list.toArray(new String[list.size()]));
		for (int i = 0; i < list.size(); i++) {
			System.out.println(systemPackages[i]);
			System.out.println(systemPaths[i]);
		}
	}

	public static void main(String[] args) {

	
	}
}

class PropertyReadAction implements PrivilegedAction<String> {

	private final String key;
	private final String defVal;

	PropertyReadAction(final String key) {
		this(key, null);
	}

	PropertyReadAction(final String key, final String defVal) {
		this.key = key;
		this.defVal = defVal;
	}

	public String run() {
		return System.getProperty(key, defVal);
	}
}