dbforumthread.java

这是学习Java必须读懂两套源代码

/**
 * Copyright (C) 2001 Yasna.com. All rights reserved.
 *
 * ===================================================================
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        Yasna.com (http://www.yasna.com)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Yazd" and "Yasna.com" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please
 *    contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Yazd",
 *    nor may "Yazd" appear in their name, without prior written
 *    permission of Yasna.com.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL YASNA.COM OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Yasna.com. For more information
 * on Yasna.com, please see <http://www.yasna.com>.
 */

/**
 * Copyright (C) 2000 CoolServlets.com. All rights reserved.
 *
 * ===================================================================
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        CoolServlets.com (http://www.coolservlets.com)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Jive" and "CoolServlets.com" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please
 *    contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Jive",
 *    nor may "Jive" appear in their name, without prior written
 *    permission of CoolServlets.com.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL COOLSERVLETS.COM OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of CoolServlets.com. For more information
 * on CoolServlets.com, please see <http://www.coolservlets.com>.
 */

package com.Yasna.forum.database;

import java.sql.*;
import java.util.Date;
import java.util.Iterator;

import com.Yasna.forum.*;
import com.Yasna.util.Cacheable;
import com.Yasna.util.CacheSizes;

/**
 * Database implementation of the ForumThread interface.
 *
 * @see ForumThread
 */
public class DbForumThread implements ForumThread, Cacheable {

    /** DATABASE QUERIES **/
    private static final String MESSAGE_COUNT =
        "SELECT count(*) FROM yazdMessage WHERE threadID=?";
    private static final String ADD_MESSAGE =
        "INSERT INTO yazdMessageTree(parentID,childID) VALUES(?,?)";
    private static final String MOVE_MESSAGE =
        "UPDATE yazdMessageTree SET parentID=? WHERE childID=?";
    private static final String CHANGE_MESSAGE_THREAD =
        "UPDATE yazdMessage SET threadID=? WHERE messageID=?";
    private static final String UPDATE_THREAD_MODIFIED_DATE =
        "UPDATE yazdThread SET modifiedDate=? WHERE threadID=?";
    private static final String DELETE_MESSAGE1 =
        "DELETE FROM yazdMessageTree WHERE childID=?";
    private static final String DELETE_MESSAGE2 =
        "DELETE FROM yazdMessage WHERE messageID=?";
    private static final String DELETE_MESSAGE_PROPERTIES =
        "DELETE FROM yazdMessageProp WHERE messageID=?";
    private static final String LOAD_THREAD =
        "SELECT rootMessageID, creationDate, modifiedDate FROM yazdThread WHERE threadID=?";
    private static final String INSERT_THREAD =
        "INSERT INTO yazdThread(threadID,forumID, rootMessageID,creationDate," +
        "modifiedDate,approved) VALUES(?,?,?,?,?,?)";
    private static final String SAVE_THREAD =
        "UPDATE yazdThread SET rootMessageID=?, creationDate=?, " +
        "modifiedDate=? WHERE threadID=?";

    private int id = -1;
    //Temporary object reference for when inserting new record.
    private ForumMessage rootMessage;
    private int rootMessageID;
    private java.util.Date creationDate;
    private java.util.Date modifiedDate;
    private boolean approved;

    /**
     * Indicates if the object is ready to be saved or not. An object is not
     * ready to be saved if it has just been created and has not yet been added
     * to its container. For example, a message added to a thread, etc.
     */
    private boolean isReadyToSave = false;

    /**
     * The forum allows us access to the message filters.
     */
    private DbForum forum;

    /**
     * The factory provides services such as db connections and logging.
     */
    private DbForumFactory factory;

    /**
     * Creates a new DbForumThread. The supplied message object is used to
     * derive the name of the thread (subject of message), as well as the
     * creation date and modified date of thread.
     *
     * @param rootMessage the root message of the thread.
     */
    protected DbForumThread(ForumMessage rootMessage, boolean approved,
            DbForum forum, DbForumFactory factory) throws UnauthorizedException
    {
        this.id = DbSequenceManager.nextID("ForumThread");
        this.forum = forum;
        this.factory = factory;
        this.rootMessage = rootMessage;
        this.rootMessageID = rootMessage.getID();
        //Set the creation and modified dates to be the same as those of
        //root message.
        long rootMessageTime = rootMessage.getCreationDate().getTime();
        this.creationDate = new java.util.Date(rootMessageTime);
        this.modifiedDate = new java.util.Date(rootMessageTime);
        this.approved = approved;
    }

    /**
     * Loads a DbForumThread from the database based on its id.
     *
     * @param id in unique id of the ForumThread to load.
     * @param forum the Forum that the thread belongs to.
     * @param factory a ForumFactory to use for loading.
     */
    protected DbForumThread(int id, DbForum forum, DbForumFactory factory)
            throws ForumThreadNotFoundException
    {
        this.id = id;
        this.forum = forum;
        this.factory = factory;
        loadFromDb();
        isReadyToSave = true;
    }

    //FROM THE FORUMMESSAGE INTERFACE//

    public int getID() {
        return id;
    }

    public String getName() {
        return getRootMessage().getSubject();
    }

    public java.util.Date getCreationDate() {
        return creationDate;
    }

    public void setCreationDate(java.util.Date creationDate)
            throws UnauthorizedException
    {
        this.creationDate = creationDate;
        //Only save to the db if the object is ready
        if (!isReadyToSave) {
            return;
        }
        saveToDb();
    }

    public java.util.Date getModifiedDate() {
        return modifiedDate;
    }

    public void setModifiedDate(java.util.Date modifiedDate)
            throws UnauthorizedException
    {
        this.modifiedDate = modifiedDate;
        //Only save to the db if the object is ready
        if (!isReadyToSave) {
            return;
        }
        saveToDb();
    }

    public Forum getForum() {
        return forum;
    }

    public ForumMessage getMessage(int messageID)
            throws ForumMessageNotFoundException
    {
        ForumMessage message = factory.getMessage(messageID);

        //Apply filters to message.
        message = forum.applyFilters(message);
        return message;
    }

    public ForumMessage getRootMessage()  {
        try {
            return getMessage(rootMessageID);
        }
        catch (ForumMessageNotFoundException e) {
            System.err.println("Could not load root message with id " + rootMessageID);
            e.printStackTrace();
            return null;
        }
        /*DbForumMessage message = (DbForumMessage)factory.cacheManager.get(
                DbCacheManager.MESSAGE_CACHE,
                new Integer(rootMessageID)
        );
        if (message == null) {
            //Load and add to cache
            try {
                message = new DbForumMessage(rootMessageID, factory);
                factory.cacheManager.add(DbCacheManager.MESSAGE_CACHE, new Integer(rootMessageID), message);
            }
            catch (ForumMessageNotFoundException e) {
                System.err.println("Could not load root message with id " + rootMessageID);
                e.printStackTrace();
            }
        }
        return message;
        */
    }

    public int getMessageCount() {
        int messageCount = 0;
        Connection con = null;
        PreparedStatement pstmt = null;
        try {
            con = DbConnectionManager.getConnection();
            pstmt = con.prepareStatement(MESSAGE_COUNT);
            pstmt.setInt(1, id);
            ResultSet rs = pstmt.executeQuery();
            rs.next();
            messageCount = rs.getInt(1);
        }
        catch( SQLException sqle ) {
            System.err.println("DbForumThread:getMessageCount() failed: "+sqle);
        }
        finally {
            try {  pstmt.close(); }
            catch (Exception e) { e.printStackTrace(); }
            try {  con.close();   }
            catch (Exception e) { e.printStackTrace(); }
        }
        return messageCount;
    }

    public void addMessage(ForumMessage parentMessage, ForumMessage newMessage) {
        boolean abortTransaction = false;
        boolean supportsTransactions = false;
        //Add message to db
        Connection con = null;
        PreparedStatement pstmt = null;
        try {
            con = DbConnectionManager.getConnection();
            supportsTransactions = con.getMetaData().supportsTransactions();
            if (supportsTransactions) {
                con.setAutoCommit(false);
            }

            //Now, insert the message into the database.
            //Now, insert the message into the database.
            ((ForumMessageProxy)newMessage).insertIntoDb(con, this);

            pstmt = con.prepareStatement(ADD_MESSAGE);
            pstmt.setInt(1, parentMessage.getID());
            pstmt.setInt(2, newMessage.getID());
            pstmt.executeUpdate();
            pstmt.close();
        }
        catch( Exception e ) {
            e.printStackTrace();
            abortTransaction = true;
            return;
        }
        finally {
            try {
                if (supportsTransactions) {
                    if (abortTransaction == true) {
                        con.rollback();
                    }
                    else {
                        con.commit();
                    }
                }
            }
            catch (Exception e) { e.printStackTrace(); }
            try {
                if (supportsTransactions) {
                    con.setAutoCommit(true);
                }
                con.close();
            }
            catch (Exception e) { e.printStackTrace(); }
        }

        //Added new message, so update the modified date of this thread
        updateModifiedDate(newMessage.getModifiedDate());
        //Also, update the modified date of the forum
        DbForum dbForum = (DbForum)factory.cacheManager.get(
                DbCacheManager.FORUM_CACHE,
                new Integer(forum.getID())
            );
        if (dbForum != null) {
            dbForum.updateModifiedDate(modifiedDate);
        }
        else {
            forum.updateModifiedDate(modifiedDate);
        }
    }

    public void deleteMessage(ForumMessage message)
            throws UnauthorizedException
    {
        //Skip null messages or the case that we're already deleting the thread.
        if (message == null) {
            return;
        }
        //If the message does not belong to this thread, don't perform delete.