protected function findTemplate()
    {
        if ($this->_path == false) {
            throw new PHPTAL_ConfigurationException('No template file specified');
        }

        // template source already defined
        if ($this->_source) {
            return;
        }

        if (!$this->resolvers && !$this->_repositories) {
            $this->_source = new PHPTAL_FileSource($this->_path);
        } else {
            foreach ($this->resolvers as $resolver) {
                $source = $resolver->resolve($this->_path);
                if ($source) {
                    $this->_source = $source;
                    return;
                }
            }

            $resolver = new PHPTAL_FileSourceResolver($this->_repositories);
            $this->_source = $resolver->resolve($this->_path);
        }

        if (!$this->_source) {
            throw new PHPTAL_IOException('Unable to locate template file '.$this->_path);
        }
    }