storefrontmemorydatabase.java

《基于Eclipse的开源框架技术与实战》[第5章]随书源码

package com.free.struts.storefront.service.memory;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;

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.xml.sax.Attributes;

import com.free.struts.storefront.businessobjects.CustomerBO;
import com.free.struts.storefront.businessobjects.ItemBO;

/**
 * <p>Title: Eclipse Plugin Development</p>
 * <p>Description: Free download</p>
 * <p>Copyright: Copyright (c) 2006</p>
 * <p>Company: Free</p>
 * @author gan.shu.man
 * @version 1.0
 */

public final class StorefrontMemoryDatabase {

	private static StorefrontMemoryDatabase Singleton = null;

	/**
	 * Logging output for this user database instance.
	 */
	private Log log = LogFactory.getLog(this.getClass());
	private HashMap users = new HashMap();
	private HashMap items = new HashMap();

	/**
	 * 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 static StorefrontMemoryDatabase getInstance() {
		synchronized (StorefrontMemoryDatabase.class) {
			if (Singleton == null) {
				Singleton = new StorefrontMemoryDatabase();
			}
		}
		return Singleton;
	}

	public String getPathname() {
		return (this.pathname);
	}

	public void setPathname(String pathname) {
		this.pathname = pathname;
		pathnameOld = pathname + ".old";
		pathnameNew = pathname + ".new";
	}

	/**
	 * <p>Finalize access to the underlying persistence layer.</p>
	 *
	 * @exception Exception if a database access error occurs
	 */
	public void close() throws Exception {
		//save();
	}

	public void save() throws Exception {
	}

	public ItemBO createItem(String oid) {
		synchronized (items) {
			if (items.get(oid) != null) {
				throw new IllegalArgumentException(
					"Duplicate item '" + oid + "'");
			}
			if (log.isTraceEnabled()) {
				log.trace("Creating item '" + oid + "'");
			}
			ItemBO item = new ItemBO();

			item.setId(new Integer(oid));

			synchronized (items) {
				items.put(oid, item);
			}
			return (item);
		}

	}

	public CustomerBO createCustomer(String oid, String email, String passwd) {

		synchronized (users) {
			if (users.get(email) != null) {
				throw new IllegalArgumentException(
					"Duplicate user '" + email + "'");
			}
			if (log.isTraceEnabled()) {
				log.trace("Creating user '" + email + "'");
			}
			CustomerBO customer = new CustomerBO();
			customer.setId(new Integer(oid));
			customer.setEmail(email);
			customer.setPassword(passwd);
			synchronized (users) {
				users.put(oid, customer);
			}
			return (customer);
		}

	}

	public CustomerBO findCustomer(String oid) {
		return ((CustomerBO) users.get(oid));
	}

	public ItemBO findItem(String oid) {
		return ((ItemBO) items.get(oid));
	}

	public Collection getFeaturedItems() {
		return items.values();
	}

	public CustomerBO authenticateUser(String email, String passwd) {
		CustomerBO aUser = null;

		if (email == null || passwd == null) {
			return null;
		}

		Iterator iter = users.values().iterator();
		while (iter.hasNext()) {
			CustomerBO candidateCustomer = (CustomerBO) iter.next();
			if (email.equals(candidateCustomer.getEmail())
				&& passwd.equals(candidateCustomer.getPassword())) {
				aUser = candidateCustomer;
				break;
			}
		}

		return aUser;
	}

	public void open() {		
		BufferedInputStream bis = null;

		try {

			// Acquire an input stream to our database file
			if (log.isDebugEnabled()) {
				log.debug("Loading database from '" + pathname + "'");
			}

			InputStream is =
				Thread
					.currentThread()
					.getContextClassLoader()
					.getResourceAsStream(
					pathname);
			
			bis = new BufferedInputStream(is);			

			// 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/product",
				new MemoryProductCreationFactory(this));

			// Parse the input stream to initialize our database
			digester.parse(bis);
			bis.close();
			bis = null;
			

		} catch (Exception e) {
			log.error("Loading database from '" + pathname + "':", e);
		} finally {

			if (bis != null) {
				try {
					bis.close();
				} catch (Throwable t) {
					;
				}
				bis = null;				
			}

		}

	}

	/**
	 * Digester object creation factory for subscription instances.
	 */
	class MemoryProductCreationFactory implements ObjectCreationFactory {

		public MemoryProductCreationFactory(StorefrontMemoryDatabase database) {
			this.database = database;
		}

		private StorefrontMemoryDatabase 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 oid = attributes.getValue("oid");
			String name = attributes.getValue("name");
			String image = attributes.getValue("image");
			String priceStr = attributes.getValue("price");
			String desc = attributes.getValue("description");

			ItemBO item = database.createItem(oid);
			item.setDescription(desc);
			item.setSmallImageURL(image);
			item.setLargeImageURL(image);
			item.setDisplayLabel(name);

			Double price = null;
			if (priceStr != null) {
				try {
					item.setBasePrice(Double.valueOf(priceStr));
				} catch (Exception ex) {
					ex.printStackTrace();
				}
			}
			System.out.println("Putting " + oid + " " + item);
			items.put(oid, item);
			return (item);
		}

	}

	/**
	 * Digester object creation factory for user instances.
	 */
	class MemoryUserCreationFactory implements ObjectCreationFactory {

		public MemoryUserCreationFactory(StorefrontMemoryDatabase database) {
			this.database = database;
		}

		private StorefrontMemoryDatabase 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 oid = attributes.getValue("oid");
			String email = attributes.getValue("email");
			String password = attributes.getValue("password");

			CustomerBO cust = database.createCustomer(oid, email, password);
			cust.setFirstName(attributes.getValue("firstname"));
			cust.setLastName(attributes.getValue("lastname"));

			return (cust);
		}
	}

}