/*
* $Id: MemoryUserDatabase.java 471754 2006-11-06 14:55:09Z husted $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.struts.apps.mailreader.dao.impl.memory;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.HashMap;
import org.apache.commons.digester.Digester;
import org.apache.commons.digester.ObjectCreationFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.apps.mailreader.dao.Subscription;
import org.apache.struts.apps.mailreader.dao.User;
import org.apache.struts.apps.mailreader.dao.UserDatabase;
import org.xml.sax.Attributes;
/**
* <p>Concrete implementation of {@link UserDatabase} for an in-memory
* database backed by an XML data file.</p>
*
* @version $Rev: 471754 $ $Date: 2006-11-06 15:55:09 +0100 (Lun, 06 nov 2006) $
* @since Struts 1.1
*/
public class MemoryUserDatabase implements UserDatabase {
// ----------------------------------------------------------- Constructors
// ----------------------------------------------------- Instance Variables
/**
* Logging output for this user database instance.
*/
private Log log = LogFactory.getLog(this.getClass());
/**
* The {@link User}s associated with this UserDatabase, keyed by username.
*/
private HashMap users = new HashMap();
private boolean open = false;
// ------------------------------------------------------------- Properties
/**
* Absolute pathname to the persistent file we use for loading and storing
* persistent data.
*/
private String pathname = null;
private String pathnameOld = null;
private String pathnameNew = null;
public String getPathname() {
return (this.pathname);
}
public void setPathname(String pathname) {
this.pathname = pathname;
pathnameOld = pathname + ".old";
pathnameNew = pathname + ".new";
}
// --------------------------------------------------------- Public Methods
// See interface for Javadoc
public void close() throws Exception {
save();
this.open = false;
}
// See interface for Javadoc
public User createUser(String username) {
synchronized (users) {
if (users.get(username) != null) {
throw new IllegalArgumentException("Duplicate user '" +
username + "'");
}
if (log.isTraceEnabled()) {
log.trace("Creating user '" + username + "'");
}
MemoryUser user = new MemoryUser(this, username);
synchronized (users) {
users.put(username, user);
}
return (user);
}
}
// See interface for Javadoc
public User findUser(String username) {
synchronized (users) {
return ((User) users.get(username));
}
}
// See interface for Javadoc
public User[] findUsers() {
synchronized (users) {
User results[] = new User[users.size()];
return ((User[]) users.values().toArray(results));
}
}
// See interface for Javadoc
public void open() throws Exception {
FileInputStream fis = null;
BufferedInputStream bis = null;
try {
// Acquire an input stream to our database file
if (log.isDebugEnabled()) {
log.debug("Loading database from '" + pathname + "'");
}
fis = new FileInputStream(pathname);
bis = new BufferedInputStream(fis);
// Construct a digester to use for parsing
Digester digester = new Digester();
digester.push(this);
digester.setValidating(false);
digester.addFactoryCreate
("database/user",
new MemoryUserCreationFactory(this));
digester.addFactoryCreate
("database/user/subscription",
new MemorySubscriptionCreationFactory());
// Parse the input stream to initialize our database
digester.parse(bis);
bis.close();
bis = null;
fis = null;
this.open = true;
} catch (Exception e) {
log.error("Loading database from '" + pathname + "':", e);
throw e;
} finally {
if (bis != null) {
try {
bis.close();
} catch (Throwable t) {
// do nothing
}
bis = null;
fis = null;
}
}
}
// See interface for Javadoc
public void removeUser(User user) {
if (!(this == user.getDatabase())) {
throw new IllegalArgumentException
("User not associated with this database");
}
if (log.isTraceEnabled()) {
log.trace("Removing user '" + user.getUsername() + "'");
}
synchronized (users) {
users.remove(user.getUsername());
}
}
// See interface for Javadoc
public void save() throws Exception {
if (log.isDebugEnabled()) {
log.debug("Saving database to '" + pathname + "'");
}
File fileNew = new File(pathnameNew);
PrintWriter writer = null;
try {
// Configure our PrintWriter
FileOutputStream fos = new FileOutputStream(fileNew);
OutputStreamWriter osw = new OutputStreamWriter(fos);
writer = new PrintWriter(osw);
// Print the file prolog
writer.println("<?xml version='1.0'?>");
writer.println("<database>");
// Print entries for each defined user and associated subscriptions
User yusers[] = findUsers();
for (int i = 0; i < yusers.length; i++) {
writer.print(" ");
writer.println(yusers[i]);
Subscription subscriptions[] =
yusers[i].getSubscriptions();
for (int j = 0; j < subscriptions.length; j++) {
writer.print(" ");
writer.println(subscriptions[j]);
writer.print(" ");
writer.println("</subscription>");
}
writer.print(" ");
writer.println("</user>");
}
// Print the file epilog
writer.println("</database>");
// Check for errors that occurred while printing
if (writer.checkError()) {
writer.close();
fileNew.delete();
throw new IOException
("Saving database to '" + pathname + "'");
}
writer.close();
writer = null;
} catch (IOException e) {
if (writer != null) {
writer.close();
}
fileNew.delete();
throw e;
}
// Perform the required renames to permanently save this file
File fileOrig = new File(pathname);
File fileOld = new File(pathnameOld);
if (fileOrig.exists()) {
fileOld.delete();
if (!fileOrig.renameTo(fileOld)) {
throw new IOException
("Renaming '" + pathname + "' to '" + pathnameOld + "'");
}
}
if (!fileNew.renameTo(fileOrig)) {
if (fileOld.exists()) {
fileOld.renameTo(fileOrig);
}
throw new IOException
("Renaming '" + pathnameNew + "' to '" + pathname + "'");
}
fileOld.delete();
}
public boolean isOpen() {
return this.open;
}
}
/**
* Digester object creation factory for subscription instances.
*/
class MemorySubscriptionCreationFactory implements ObjectCreationFactory {
private Digester digester = null;
public Digester getDigester() {
return (this.digester);
}
public void setDigester(Digester digester) {
this.digester = digester;
}
public Object createObject(Attributes attributes) {
String host = attributes.getValue("host");
User user = (User) digester.peek();
Subscription subscription = user.createSubscription(host);
String autoConnect = attributes.getValue("autoConnect");
if (autoConnect == null) {
autoConnect = "false";
}
if ("true".equalsIgnoreCase(autoConnect) ||
"yes".equalsIgnoreCase(autoConnect)) {
subscription.setAutoConnect(true);
} else {
subscription.setAutoConnect(false);
}
subscription.setPassword(attributes.getValue("password"));
subscription.setType(attributes.getValue("type"));
subscription.setUsername(attributes.getValue("username"));
return (subscription);
}
}
/**
* Digester object creation factory for user instances.
*/
class MemoryUserCreationFactory implements ObjectCreationFactory {
public MemoryUserCreationFactory(MemoryUserDatabase database) {
this.database = database;
}
private MemoryUserDatabase database = null;
private Digester digester = null;
public Digester getDigester() {
return (this.digester);
}
public void setDigester(Digester digester) {
this.digester = digester;
}
public Object createObject(Attributes attributes) {
String username = attributes.getValue("username");
User user = database.createUser(username);
user.setFromAddress(attributes.getValue("fromAddress"));
user.setFullName(attributes.getValue("fullName"));
user.setPassword(attributes.getValue("password"));
user.setReplyToAddress(attributes.getValue("replyToAddress"));
return (user);
}
}