/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.validation.client.constraints;

import java.math.BigDecimal;

import javax.validation.ConstraintValidator;
import javax.validation.constraints.Digits;

/**
 * Abstract {@link Digits} constraint validator implementation for a
 * <code>T</code>.
 *
 * @param <T> the type of object to validate
 */
public abstract class AbstractDigitsValidator<T> implements
    ConstraintValidator<Digits, T> {

  private int fraction;
  private int integer;

  @Override
  public final void initialize(Digits constraintAnnotation) {
    if (!(constraintAnnotation.fraction() >= 0)) {
      throw new IllegalArgumentException(
          "@Digits.fraction must be a nonnegative nubmer");
    }
    if (!(constraintAnnotation.integer() >= 0)) {
      throw new IllegalArgumentException(
          "@Digits.integer must be a nonnegative nubmer");
    }
    fraction = constraintAnnotation.fraction();
    integer = constraintAnnotation.integer();
  }

  protected final boolean isValid(BigDecimal bigValue) {
    int integerLength = bigValue.precision() - bigValue.scale();
    if (integerLength > integer) {
      return false;
    }
    int fractionalLength = bigValue.scale() < 0 ? 0 : bigValue.scale();
    return fractionalLength <= fraction;
  }
}