dbuseriterator.java

一套完整的工商12315的源程序jsp部分在12315里,后台JAVA部分在gs12315src里,没有打包数据库.

/*
 * DbUserIterator.java
 *
 * Created on 2001年7月4日, 上午10:32
 */

package com.gs.db.dbimp;

import com.gs.db.*;

import java.util.Iterator;
import java.util.ListIterator;
import java.util.ArrayList;
import java.sql.*;

/**
 * An Iterator for all the users in the system. Those wishing to integrate
 * Jive into their own User system should also modify this class.
 */
public class DbUserIterator implements Iterator, ListIterator {

    /** DATABASE QUERIES **/
    private static final String ALL_USERS =
        "SELECT userid from gsUser where status>=0";

    private int currentIndex = -1;
    private int [] users;

    private ProfileManager profileManager;

    protected DbUserIterator(ProfileManager profileManager) {
        this.profileManager = profileManager;
        //We don't know how many results will be returned, so store them
        //in an ArrayList.
        ArrayList tempUsers = new ArrayList();
        Connection con = null;
        PreparedStatement pstmt = null;
        try {
            con = DbConnectionManager.getConnection();
            pstmt = con.prepareStatement(ALL_USERS);
            ResultSet rs = pstmt.executeQuery();
            while (rs.next()) {
                tempUsers.add(new Integer(rs.getInt("userid")));
            }
        }
        catch( SQLException sqle ) {
            System.err.println("Error in DbUserIterator:constructor()-" + sqle);
        }
        finally {
            try {  pstmt.close(); }
            catch (Exception e) { e.printStackTrace(); }
            try {  con.close();   }
            catch (Exception e) { e.printStackTrace(); }
        }
        //Now copy into an array.
        users = new int[tempUsers.size()];
        for (int i=0; i<users.length; i++) {
            users[i] = ((Integer)tempUsers.get(i)).intValue();
        }
    }

    protected DbUserIterator(ProfileManager profileManager, int startIndex,
            int numResults)
    {
        this.profileManager = profileManager;

        int[] tempUsers = new int[numResults];
        //It's very possible that there might not be as many results to get
        //as we requested. Therefore, we keep track of how many results we
        //get by keeping a count.
        int userCount = 0;

        Connection con = null;
        PreparedStatement pstmt = null;

        try {
            con = DbConnectionManager.getConnection();
            pstmt = con.prepareStatement(ALL_USERS);
            ResultSet rs = pstmt.executeQuery();
            //Move to start of index
            for (int i=0; i<startIndex; i++) {
                rs.next();
            }
            //Now read in desired number of results
            for (int i=0; i<numResults; i++) {
                if (rs.next()) {
                    tempUsers[userCount] = rs.getInt("userid");
                    userCount++;
                }
                else {
                    break;
                }
            }
        }
        catch( SQLException sqle ) {
            System.err.println("Error in DbUserIterator:constructor()-" + sqle);
        }
        finally {
            try {  pstmt.close(); }
            catch (Exception e) { e.printStackTrace(); }
            try {  con.close();   }
            catch (Exception e) { e.printStackTrace(); }
        }
        users = new int[userCount];
        for (int i=0; i<userCount; i++) {
            users[i] = tempUsers[i];
        }
    }

    /**
     * Returns true if there are more users left to iteratate through forwards.
     */
    public boolean hasNext() {
        return (currentIndex+1 < users.length);
    }

    /**
     * Returns true if there are more users left to iteratore through backwards.
     */
    public boolean hasPrevious() {
        return (currentIndex > 0);
    }

    /**
     * Returns the next User.
     *
     * @return the next User.
     * @throws NoSuchElementException if there are no more elements to return.
     */
    public Object next() throws java.util.NoSuchElementException {
        User user = null;
        currentIndex++;
        if (currentIndex >= users.length) {
            throw new java.util.NoSuchElementException();
        }
        try {
            user = profileManager.getUser(users[currentIndex]);
        }
        catch (UserNotFoundException gnfe) {
            gnfe.printStackTrace();
        }
        return user;
    }

    /**
     * For security reasons, the add operation is not supported. Use
     * ProfileManager instead.
     *
     * @see ProfileManager
     */
    public void add(Object o) throws UnsupportedOperationException {
        throw new UnsupportedOperationException();
    }

    /**
     * For security reasons, the remove operation is not supported. Use
     * ProfileManager instead.
     *
     * @see ProfileManager
     */
    public void remove() {
        throw new UnsupportedOperationException();
    }

    /**
     * For security reasons, the set operation is not supported. Use
     * ProfileManager instead.
     *
     * @see ProfileManager
     */
    public void set(Object o) throws UnsupportedOperationException {
        throw new UnsupportedOperationException();
    }

    /**
     * Returns the index number that would be returned with a call to next().
     */
    public int nextIndex() {
        return currentIndex+1;
    }

    /**
     * Returns the previous user.
     */
    public Object previous() throws java.util.NoSuchElementException {
        User user = null;
        currentIndex--;
        if (currentIndex < 0) {
            currentIndex++;
            throw new java.util.NoSuchElementException();
        }
        try {
            user = profileManager.getUser(users[currentIndex]);
        }
        catch (UserNotFoundException gnfe) {
            System.err.println(gnfe);
        }
        return user;
    }

    /**
     * Returns the index number that would be returned with a call to previous().
     */
    public int previousIndex() {
        return currentIndex-1;
    }
}