simplepersistence.java

aglet的部分源码

package com.ibm.aglets.tahiti;

/*
 * @(#)SimplePersistence.java
 * 
 * IBM Confidential-Restricted
 * 
 * OCO Source Materials
 * 
 * 03L7246 (c) Copyright IBM Corp. 1996, 1998
 * 
 * The source code for this program is not published or otherwise
 * divested of its trade secrets, irrespective of what has been
 * deposited with the U.S. Copyright Office.
 */

import com.ibm.aglets.PersistentEntry;

import java.io.File;
import java.io.IOException;
import java.util.Enumeration;
import java.security.AccessController;
import java.security.PrivilegedAction;

import com.ibm.awb.misc.FileUtils;


/**
 * @version     1.10	$Date: 2001/07/28 06:32:32 $
 * @author      Mitsuru Oshima
 */
final class SimplePersistence implements com.ibm.aglets.Persistence {
	String spool_dir;

	SimplePersistence(String str) throws IOException {
		spool_dir = str;

		// to make sure that str point to a directory.
		if (spool_dir.charAt(spool_dir.length() - 1) != File.separatorChar) {
			spool_dir += File.separator;
		} 
		final File dir = new File(spool_dir);
		boolean exists = false;
		boolean isDir = false;

		try {
			boolean[] bb = 
				(boolean[])AccessController
					.doPrivileged(new PrivilegedAction() {
				public Object run() {
					boolean[] result = new boolean[2];

					result[0] = dir.exists();
					result[1] = dir.isDirectory();
					return result;
				} 
			});

			exists = bb[0];
			isDir = bb[1];
		} catch (Exception ex) {
			ex.printStackTrace();
		} 
		if (exists && (isDir == false)) {
			throw new IOException(str + "is not a directory.");
		} 
		if (exists == false) {
			if (FileUtils.ensureDirectory(spool_dir) == false) {
				System.err.println("Failed to create new spool directory : " 
								   + str);
			} 
		} 
	}
	public PersistentEntry createEntryWith(String key) {
		final File f = new File(spool_dir + key);

		try {
			return (PersistentEntry)AccessController
				.doPrivileged(new PrivilegedAction() {
				public Object run() {
					if (!f.exists() || f.canWrite()) {
						return new SimplePEntry(f);
					} else {
						return null;
					} 
				} 
			});
		} catch (Exception ex) {
			ex.printStackTrace();
		} 
		return null;
	}
	public Enumeration entryKeys() {
		return new KeyEnumerator(spool_dir);
	}
	public PersistentEntry getEntry(String key) {
		final File f = new File(spool_dir + key);

		try {
			return (PersistentEntry)AccessController
				.doPrivileged(new PrivilegedAction() {
				public Object run() {
					if (f.exists() && f.canWrite()) {
						return new SimplePEntry(f);
					} else {
						return null;
					} 
				} 
			});
		} catch (Exception ex) {
			ex.printStackTrace();
		} 
		return null;
	}
	public void removeEntry(String key) {
		try {
			final String fSpoolDir = spool_dir;
			final String fKey = key;

			AccessController.doPrivileged(new PrivilegedAction() {
				public Object run() {
					String filename = fSpoolDir + fKey;

					(new File(filename)).delete();
					return null;
				} 
			});
		} catch (Exception ex) {
			ex.printStackTrace();
		} 
	}
}