Location: PHPKode > scripts > DATA > data/DATA/SQLType.php
<?php
/**
 * @package DATA
 */

/**
 * SQL type representation.
 * 
 * Right now there will be no support for arbitrary size math
 * operations, but these will be supported by the member
 * functions in the corresponding classes. Outboxing into native
 * php types and doing the math operations outside is discouraged.
 * 
 * All classes will provide __toString() functionality for automatic
 * outboxing into string representation. This will allow character
 * types to be used in the usual string context without having to
 * explicitly outbox the value.
 * 
 */
abstract class DATA_SQLType {
    /**
     * Flags the type to nullable or not nullable.
     * @var boolean
     */
    private $nullable;
    
    /**
     * Flags the value as null.
     * @var boolean
     */
    private $isnull;
    
    /**
     * Internal constructor. Sets the type to nullable or not nullable.
     * 
     * @param boolean $nullable True if the type is nullable.
     * @param boolean $isnull True if the initial value is null.
     */
    protected function __construct($nullable, $isnull) {
        $this->nullable = $nullable;
        $this->isnull = false;
        if ($isnull) $this->setNull();
    }
    
    /**
     * Automatically outboxes the value into a native php string.
     * 
     * @return string String representation of the value.
     */
    abstract public function __toString();
    
    /**
     * Indicates if this type is nullable.
     * 
     * @return boolean True if the type is nullable.
     */
    public function isNullable() {
        return $this->nullable;
    }
    
    /**
     * Indicates if this value is null.
     * 
     * Optionally, can be used statically passing the value by parameter.
     * 
     * @return boolean True if the value is null.
     */
    public function isNull() {
        if (isset($this)) {
            return $this->isnull;
        }
        $value = func_get_arg(0);
        if ($value instanceof DATA_SQLType) {
            return $value->isNull();
        } else {
            return is_null($value);
        }
    }
    
    /**
     * Nulls this value.
     * 
     * Throws {@link DATA_NotNullable}.
     */
    public function setNull() {
        if (!$this->nullable) {
            throw new DATA_NotNullable();
        }
        $this->isnull = true;
    }
    
    /**
     * Internally flag the value as not null.
     */
    protected function setNotNull() {
        $this->isnull = false;
    }
    
    /**
     * Outboxes the value into a php native value.
     * 
     * @return mixed Php native value.
     */
    public function outbox() {
        if ($this->isnull) return null;
        else return $this->__toString();
    }
}
?>
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