Preconditions.java

/* 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 parquet;

/**
 * Utility for parameter validation
 *
 * @author Julien Le Dem
 *
 */
public final class Preconditions {
  private Preconditions() { }

  /**
   * @param o the param to check
   * @param name the name of the param for the error message
   * @return the validated o
   * @throws NullPointerException if o is null
   */
  public static <T> T checkNotNull(T o, String name) throws NullPointerException {
    if (o == null) {
      throw new NullPointerException(name + " should not be null");
    }
    return o;
  }

  /**
   * @param valid whether the argument is valid
   * @param message error message if the argument is not valid
   * @throws IllegalArgumentException if !valid
   */
  public static void checkArgument(boolean valid, String message) throws IllegalArgumentException {
    if (!valid) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * @param valid whether the argument is valid
   * @param message error message if the argument is not valid
   * @throws IllegalStateException if !valid
   */
  public static void checkState(boolean valid, String message) throws IllegalStateException {
    if (!valid) {
      throw new IllegalStateException(message);
    }
  }
}