dbforumcategory.java

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package com.jivesoftware.forum.database;

import com.jivesoftware.forum.*;
import com.jivesoftware.util.*;

import java.util.*;
import java.util.LinkedList;
import java.util.Date;
import java.sql.*;
import java.io.IOException;

/**
 * Database implementation of the ForumCategory interface. The SQL tree structure we
 * use is Joe Celko's. For more information, see:
 * http://searchdatabase.techtarget.com/tip/1,289483,sid13_gci537290,00.html.
 * <p>
 * The lft and rgt column values are responsible for defining the tree.
 * An example tree with the lft and rgt column values (respectively) is as
 * follows: <pre>
 *
 *            (1,12)
 *          /       \
 *      (2,3)      (4,11)
 *               /   |   \
 *             /     |    \
 *          (5,6)  (7,8) (9,10)
 * </pre>
 *
 * As you can see from the tree, the lft and rgt values of a child are
 * always between the values of its parent. We can use this property to
 * load the entire tree into memory using a single select. The simple way to
 * to determine the lft and rgt values of an arbitrary tree structure is to
 * label lft then rgt by traversing the tree in depth-first order.
 */
public class DbForumCategory implements ForumCategory, Cacheable {

    /** DATABASE QUERIES **/
    protected static final String FIND_FORUM_INDEX =
        "SELECT categoryIndex FROM jiveForum WHERE forumID=? AND categoryID=?";
    protected static final String FORUM_IN_CATEGORY_COUNT =
        "SELECT count(categoryIndex) FROM jiveForum WHERE categoryID=?";
    protected static final String SHIFT_FORUM_INDEX_1 =
        "UPDATE jiveForum SET categoryIndex=categoryIndex+1 WHERE categoryID=? " +
        "AND categoryIndex >= ? AND categoryIndex <?";
    protected static final String SHIFT_FORUM_INDEX_2 =
        "UPDATE jiveForum SET categoryIndex=categoryIndex-1 WHERE categoryID=? " +
        "AND categoryIndex <= ? AND categoryIndex > ?";
    protected static final String SHIFT_CATEGORY_INDEX_1 =
        "UPDATE jiveCategory SET lft=lft+?, rgt=rgt+? WHERE lft>=? AND lft<?";
    protected static final String SHIFT_CATEGORY_INDEX_2 =
        "UPDATE jiveCategory SET lft=lft+?, rgt=rgt+? WHERE lft>? AND rgt>? AND rgt<=?";
    private static final String SET_FORUM_INDEX =
        "UPDATE jiveForum SET categoryIndex=? WHERE forumID=?";
    private static final String MOVE_FORUM =
        "UPDATE jiveForum SET categoryID=?, categoryIndex=? WHERE forumID=?";
    private static final String LOAD_CATEGORY =
        "SELECT name, description, creationDate, modifiedDate, lft, rgt FROM " +
        "jiveCategory WHERE categoryID=?";
    private static final String FIND_LFT_RGT =
        "SELECT lft, rgt FROM jiveCategory WHERE categoryID=?";
    private static final String CHANGE_LFT =
        "UPDATE jiveCategory SET lft=lft+? WHERE lft > ? AND rgt > ?";
    private static final String CHANGE_RGT =
        "UPDATE jiveCategory SET rgt=rgt+? WHERE rgt >= ?";
    private static final String UPDATE_CATEGORY_MODIFIED_DATE =
        "UPDATE jiveCategory SET modifiedDate=? WHERE lft<? AND rgt>?";
    private static final String INSERT_CATEGORY =
        "INSERT INTO jiveCategory(categoryID,name,description,creationDate," +
        "modifiedDate,lft,rgt) VALUES (?,?,?,?,?,?,?)";
    private static final String SAVE_CATEGORY =
        "UPDATE jiveCategory SET name=?, description=?, creationDate=?, " +
        "modifiedDate=? WHERE categoryID=?";
    private static final String DELETE_CATEGORY =
        "DELETE FROM jiveCategory WHERE categoryID=?";
    private static final String LOAD_PROPERTIES =
        "SELECT name, propValue FROM jiveCategoryProp WHERE categoryID=?";
    private static final String DELETE_PROPERTY =
        "DELETE FROM jiveCategoryProp WHERE categoryID=? AND name=?";
    private static final String UPDATE_PROPERTY =
        "UPDATE jiveCategoryProp SET propValue=? WHERE name=? AND categoryID=?";
    private static final String INSERT_PROPERTY =
        "INSERT INTO jiveCategoryProp(categoryID,name,propValue) VALUES(?,?,?)";

    private static final String CATEGORY_COUNT =
        "SELECT count(*) FROM jiveCategory";
    private static final String LOAD_CATEGORY_TREE =
        "SELECT categoryID, lft, rgt FROM jiveCategory ORDER BY lft ASC";

    private static LongTree categoryTree;

    /**
     * Number of forumID's per cache block.
     */
    public static final int BLOCK_SIZE = 50;

    // Constant for an empty bock. This is returned in the case that there are
    // no results when trying to load a thread or message block.
    private static final long[] EMPTY_BLOCK = new long[0];

    // A ResultFilter is used to filter and sort the values that are returned
    // from the forums() method.
    private static final ResultFilter DEFAULT_FORUM_FILTER =
            ResultFilter.createDefaultForumFilter();

    private static final long serialVersionUID = 01L;

    /**
     * Doing operations on the category tree is dangerious for databases without
     * transaction support. To help minimize the risk, we use a static lock
     * that must be acquired before modifying the tree.
     */
    private static Object lock = new Object();

    private long id;
    private String name;
    private String description;
    private Date creationDate;
    private Date modifiedDate;
    private Map properties;
    int lft;
    int rgt;

    // List to keep track of the keys that we insert into global caches.
    // Keeping track of the keys allows us to delete them from the caches
    // as necessary.
    private LinkedList queryKeys = new LinkedList();

    private transient DbForumFactory factory;

    /**
     * Loads an existing category.
     *
     * @param id the ID of the category to load.
     * @throws ForumCategoryNotFoundException
     */
    public DbForumCategory(long id) throws ForumCategoryNotFoundException
    {
        this.id = id;
        loadFromDb();
        init();
    }

    /**
     * Creates a new category.
     *
     * @param name the name of the new category.
     * @param description
     * @param parentCategory
     */
    public DbForumCategory(String name, String description,
            DbForumCategory parentCategory)
    {
        this.id = SequenceManager.nextID(JiveGlobals.FORUM_CATEGORY);
        this.name = name;
        this.description = description;
        long now = System.currentTimeMillis();
        creationDate = new java.util.Date(now);
        modifiedDate = new java.util.Date(now);
        insertIntoDb(parentCategory);
        properties = new Hashtable();
        init();
    }

    private void init() {
        factory = DbForumFactory.getInstance();
        if (categoryTree == null) {
            refreshCategoryTree();
        }
    }

    private void readObject(java.io.ObjectInputStream in)
            throws IOException, ClassNotFoundException
    {
        in.defaultReadObject();
        init();
    }

    public long getID() {
        return id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
        saveToDb();
        // Re-add category to cache.
        factory.cacheManager.categoryCache.put(new Long(this.id), this);
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
        saveToDb();
        // Re-add category to cache.
        factory.cacheManager.categoryCache.put(new Long(this.id), this);
    }

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

    public void setCreationDate(java.util.Date creationDate) {
       this.creationDate = creationDate;
       saveToDb();
       // Re-add category to cache.
       factory.cacheManager.categoryCache.put(new Long(this.id), this);
    }

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

    public void setModifiedDate(java.util.Date modifiedDate)
            throws UnauthorizedException
    {
        this.modifiedDate = modifiedDate;
        saveToDb();
        // Re-add category to cache.
        factory.cacheManager.categoryCache.put(new Long(this.id), this);
    }

    public String getProperty(String name) {
        return (String)properties.get(name);
    }

    public void setProperty(String name, String value) {
        // Make sure the property name and value aren't null.
        if (name == null || value == null || "".equals(name) || "".equals(value)) {
            throw new NullPointerException("Cannot set property with empty or null value.");
        }
        // See if we need to update a property value or insert a new one.
        if (properties.containsKey(name)) {
            // Only update the value in the database if the property value
            // has changed.
            if (!(value.equals(properties.get(name)))) {
                properties.put(name, value);
                updatePropertyInDb(name, value);
                // Re-add category to cache.
                factory.cacheManager.categoryCache.put(new Long(this.id), this);
            }
        }
        else {
            properties.put(name, value);
            insertPropertyIntoDb(name, value);
            // Re-add category to cache.
            factory.cacheManager.categoryCache.put(new Long(this.id), this);
        }
    }

    public void deleteProperty(String name) throws UnauthorizedException {
        // Only delete the property if it exists.
        if (properties.containsKey(name)) {
            properties.remove(name);
            deletePropertyFromDb(name);
            // Re-add category to cache.
            factory.cacheManager.categoryCache.put(new Long(this.id), this);
        }
    }

    public Iterator propertyNames() {
        return Collections.unmodifiableSet(properties.keySet()).iterator();
    }

    public int getForumCount() {
        return getForumCount(DEFAULT_FORUM_FILTER);
    }

    public int getForumCount(ResultFilter resultFilter) {
        String sql = getForumListSQL(resultFilter, true, false);
        QueryCacheKey key = new QueryCacheKey(JiveGlobals.FORUM_CATEGORY, id, sql, -1);
        return getCount(key);
    }

    public int getRecursiveForumCount() {
        return getRecursiveForumCount(DEFAULT_FORUM_FILTER);
    }

    public int getRecursiveForumCount(ResultFilter resultFilter) {
        String sql = getForumListSQL(resultFilter, true, true);
        QueryCacheKey key = new QueryCacheKey(JiveGlobals.FORUM_CATEGORY, id, sql, -1);
        return getCount(key);
    }

    public Iterator forums() {
        return forums(DEFAULT_FORUM_FILTER);
    }

    public Iterator forums(ResultFilter resultFilter) {
        String query = getForumListSQL(resultFilter, false, false);
        long [] forumBlock = getBlock(query.toString(), resultFilter.getStartIndex());
        int startIndex = resultFilter.getStartIndex();
        int endIndex;
        // If number of results is set to inifinite, set endIndex to the total
        // number of threads in the forum.
        if (resultFilter.getNumResults() == ResultFilter.NULL_INT) {
            endIndex = (int)getForumCount(resultFilter);
        }
        else {
            endIndex = resultFilter.getNumResults() + startIndex;
        }
        return new ForumBlockIterator(forumBlock, query.toString(),
                startIndex, endIndex, this.id, factory);
    }

    public Iterator recursiveForums() {
        return recursiveForums(DEFAULT_FORUM_FILTER);
    }

    public Iterator recursiveForums(ResultFilter resultFilter) {
        String query = getForumListSQL(resultFilter, false, true);
        long [] forumBlock = getBlock(query.toString(), resultFilter.getStartIndex());
        int startIndex = resultFilter.getStartIndex();
        int endIndex;
        // If number of results is set to inifinite, set endIndex to the total
        // number of threads in the forum.
        if (resultFilter.getNumResults() == ResultFilter.NULL_INT) {
            endIndex = (int)getRecursiveForumCount(resultFilter);
        }
        else {
            endIndex = resultFilter.getNumResults() + startIndex;
        }
        return new ForumBlockIterator(forumBlock, query.toString(),
                startIndex, endIndex, this.id, factory);
    }

    public void setForumIndex(Forum forum, int newIndex) {
        if (newIndex < 0 || newIndex > getForumCount() -1) {
            throw new IllegalArgumentException("Invalid index");
        }
        Connection con = null;
        PreparedStatement pstmt = null;
        boolean abortTransaction = false;
        try {
            con = ConnectionManager.getTransactionConnection();
            // First, find the old index value for the forum.
            pstmt = con.prepareStatement(FIND_FORUM_INDEX);
            pstmt.setLong(1, forum.getID());
            pstmt.setLong(2, this.id);
            ResultSet rs = pstmt.executeQuery();
            // If we didn't find a row, that means the forum does not belong
            // to the category. In that case, throw an exception.
            if (!rs.next()) {
                throw new IllegalArgumentException("Forum " + forum.getID() +
                    " is not in category " + this.id);
            }
            int oldIndex = rs.getInt(1);
            pstmt.close();

            // We need to shift the values of other forums to make room for
            // the new placement.
            if (newIndex < oldIndex) {
                pstmt = con.prepareStatement(SHIFT_FORUM_INDEX_1);
            }
            else {
                pstmt = con.prepareStatement(SHIFT_FORUM_INDEX_2);
            }
            pstmt.setLong(1, this.id);
            pstmt.setInt(2, newIndex);
            pstmt.setInt(3, oldIndex);
            pstmt.execute();
            pstmt.close();

            // Finally, update the actual entry.
            pstmt = con.prepareStatement(SET_FORUM_INDEX);
            pstmt.setInt(1, newIndex);
            pstmt.setLong(2,  forum.getID());
            pstmt.execute();
        }
        catch (SQLException sqle) {
            sqle.printStackTrace();
            abortTransaction = true;
        }
        finally {
            try {  pstmt.close(); }
            catch (Exception e) { e.printStackTrace(); }
            ConnectionManager.closeTransactionConnection(con, abortTransaction);
        }
        // Expire cache.
        clearCache();
    }