Heat a 14 inch flat bottomed wok or skillet over high heat until hot but not smoking.
Add vegetable oil, barbecued pork, cabbage, bean sprouts, celery, scallion, bamboo shoots, and mushrooms, and stir fry 2 to 3 minutes, or until the cabbage and celery are just limp.
Add soy sauce and pepper, remove from heat, and allow to cool. When mixture has cooled, place spring roll wrappers on work surface and loosely cover with a dampened cloth.
In a small bowl, combine the flour and 4 teaspoons cold water.
Place 1 wrapper on the cutting board with a corner facing you. Spread about 1/4 cup of the mixture near the bottom corner into a 3/4 by 2 inch rectangle. Fold the corner nearest you over the mixture. Roll the wrapper up once, the fold in the sides. Continue rolling the wrapper up tightly by, before you reach the end, lightly paint the far corner with the flour water mixture. Continue rolling to seal the roll into a tight cylinder. Set aside seam side down, and cover with a dampened cloth. Repeat with remaining wrappers.
In a 3 quart saucepan,. heat vegetable oil over high heat until oil temperature reaches 375F. Carefully add 3 to 4 spring rolls at a time, and fry until golden brown, turning rolls, about 2 minutes. Remove with a slotted spoon and place on a plate lined with several thicknesses of paper towels. Carefully cut in half or in thirds. Repeat with remaining spring rolls. Set oil aside to cool before discarding. Serve immediately.
Makes about 10 spring rolls.