genericobjectcollection.phpm

Professional PHP5 code for this book

<?
  class GenericObjectCollection {
    
    # Member Variables
    var $table_name;
    var $class_name;
    
    var $items_per_page;
    var $item_count = 0;
    
    var $id_array;
    
    var $obj_array;
    
    function __construct($table_name, $class_name) {
      $this->table_name = $table_name;
      $this->class_name = $class_name;
    }
    
    function AddTuple($id) {
      if (!$this->id_array) {
        $this->id_array = array();
      };
      array_push($this->id_array, $id);
      $this->item_count = sizeof($this->id_array);
    }
    
    function SetPageSize($items_per_page) {
      $this->items_per_page = $items_per_page;
    }
    
    function GetItemCount() {
      return $this->item_count;
    }
    
    function GetNumPages() {
      return(ceil($this->item_count / $this->items_per_page));
    }
    
    function _GetCommaSeparatedIDList($start_lim = 0, $end_lim = -1) {
      $s = "";
      if ($end_lim == -1) {
        $end_lim = sizeof($this->id_array)-1;
      };
      for ($i=$start_lim; $i<=$end_lim; $i++) {
        if (is_numeric($this->id_array[$i])) {
          $s = $s . $this->id_array[$i] . ",";
        };
      };
      $s = substr($s, 0, strlen($s) - 1);
      return $s;
    }
    
    function _GetIndexFromTupleID($tuple_id) {
      $index = -1;
      for ($i=0; $i<=sizeof($this->id_array)-1; $i++) {
        if ($this->id_array[$i] == $tuple_id) {
          $index = $i;
        };
      };
      return $index;
    }
    
    function PopulateObjectArray($page_num = 0) {
      $items_per_page = $this->items_per_page;
      if ($this->item_count > 0) {
        if ($page_num > 0) {
          $start_lim = ($items_per_page * ($page_num - 1));
          $end_lim = ($start_lim + $items_per_page) - 1;
          if ($end_lim > ($this->item_count-1)) {
            $end_lim = $this->item_count - 1;
          };
          $stmt = "SELECT * FROM \"" . $this->table_name . "\" WHERE id IN (" . $this->_GetCommaSeparatedIDList($start_lim, $end_lim). ")";
        } else {
          $stmt = "SELECT * FROM \"" . $this->table_name . "\" WHERE id IN (" . $this->_GetCommaSeparatedIDList(). ")";
        };
        # Perform SQL query 
        $sql = new sql(0);
        $sql->query($stmt);        
        $result_rows = $sql->get_table_hash();
        
        for ($i=0; $i<=sizeof($result_rows)-1; $i++) {
          $this_row = $result_rows[$i];
          $this_db_row_id = $this_row["id"];
          $this_index = $this->_GetIndexFromTupleID($this_db_row_id);
          if ($this_index >= 0) {
            $refObjArrayIndexObj = &$this->obj_array[$this_index];
            $s = "\$refObjArrayIndexObj = new " . $this->class_name . "(" . $this_db_row_id . ");";
            eval($s);
            $refObjArrayIndexObj->ForceLoaded();
            foreach ($this_row as $key => $value) {
              if (!(is_numeric($key))) {
                $refObjArrayIndexObj->SetField($key, $value);
              };
            };
          };
        };
      };
    }
    
    function RetrievePopulatedObjects($page_num = 0) {
      if ($page_num > 0) {
        $items_per_page = $this->items_per_page;
        # Calculate start and end limits from page number.
        $start_lim = ($items_per_page * ($page_num - 1));
        $end_lim = ($start_lim + $items_per_page) - 1;
          if ($end_lim > ($this->item_count-1)) {
            $end_lim = $this->item_count - 1;
          };        
      } else {
        $start_lim = 0;
        $end_lim = $this->item_count - 1;
      };
      $return_array = array();
      $counter = 0;
      for ($i=$start_lim; $i<=$end_lim; $i++) {
        $return_array[$counter] = $this->obj_array[$i];
        $counter++;
      };
      return($return_array);
    }
  }
?>