com.jianggujin.modulelink.util.JAssert Maven / Gradle / Ivy

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/**
 * Copyright 2018 jianggujin (www.jianggujin.com).
 * 
 * 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.jianggujin.modulelink.util;

/**
 * 常用断言
 * 
 * @author jianggujin
 *
 */
public class JAssert {
   public static void checkArgument(boolean expression) {
      if (!expression) {
         throw new IllegalArgumentException();
      }
   }

   public static void checkArgument(boolean expression, Object errorMessage) {
      if (!expression) {
         throw new IllegalArgumentException(String.valueOf(errorMessage));
      }
   }

   public static void checkArgument(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) {
      if (!expression) {
         throw new IllegalArgumentException(format(errorMessageTemplate, errorMessageArgs));
      }
   }

   public static void checkState(boolean expression) {
      if (!expression) {
         throw new IllegalStateException();
      }
   }

   public static void checkState(boolean expression, Object errorMessage) {
      if (!expression) {
         throw new IllegalStateException(String.valueOf(errorMessage));
      }
   }

   public static void checkState(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) {
      if (!expression) {
         throw new IllegalStateException(format(errorMessageTemplate, errorMessageArgs));
      }
   }

   public static  T checkNotNull(T reference) {
      if (reference == null) {
         throw new NullPointerException();
      }
      return reference;
   }

   public static  T checkNotNull(T reference, Object errorMessage) {
      if (reference == null) {
         throw new NullPointerException(String.valueOf(errorMessage));
      }
      return reference;
   }

   public static  T checkNotNull(T reference, String errorMessageTemplate, Object... errorMessageArgs) {
      if (reference == null) {
         throw new NullPointerException(format(errorMessageTemplate, errorMessageArgs));
      }
      return reference;
   }

   public static int checkElementIndex(int index, int size) {
      return checkElementIndex(index, size, "index");
   }

   public static int checkElementIndex(int index, int size, String desc) {
      if (index < 0 || index >= size) {
         throw new IndexOutOfBoundsException(badElementIndex(index, size, desc));
      }
      return index;
   }

   private static String badElementIndex(int index, int size, String desc) {
      if (index < 0) {
         return format("%s (%s) must not be negative", desc, index);
      } else if (size < 0) {
         throw new IllegalArgumentException("negative size: " + size);
      } else { // index >= size
         return format("%s (%s) must be less than size (%s)", desc, index, size);
      }
   }

   public static int checkPositionIndex(int index, int size) {
      return checkPositionIndex(index, size, "index");
   }

   public static int checkPositionIndex(int index, int size, String desc) {
      if (index < 0 || index > size) {
         throw new IndexOutOfBoundsException(badPositionIndex(index, size, desc));
      }
      return index;
   }

   private static String badPositionIndex(int index, int size, String desc) {
      if (index < 0) {
         return format("%s (%s) must not be negative", desc, index);
      } else if (size < 0) {
         throw new IllegalArgumentException("negative size: " + size);
      } else { // index > size
         return format("%s (%s) must not be greater than size (%s)", desc, index, size);
      }
   }

   public static void checkPositionIndexes(int start, int end, int size) {
      if (start < 0 || end < start || end > size) {
         throw new IndexOutOfBoundsException(badPositionIndexes(start, end, size));
      }
   }

   private static String badPositionIndexes(int start, int end, int size) {
      if (start < 0 || start > size) {
         return badPositionIndex(start, size, "start index");
      }
      if (end < 0 || end > size) {
         return badPositionIndex(end, size, "end index");
      }
      // end < start
      return format("end index (%s) must not be less than start index (%s)", end, start);
   }

   static String format(String template, Object... args) {
      template = String.valueOf(template); // null -> "null"

      StringBuilder builder = new StringBuilder(template.length() + 16 * args.length);
      int templateStart = 0;
      int i = 0;
      while (i < args.length) {
         int placeholderStart = template.indexOf("%s", templateStart);
         if (placeholderStart == -1) {
            break;
         }
         builder.append(template.substring(templateStart, placeholderStart));
         builder.append(args[i++]);
         templateStart = placeholderStart + 2;
      }
      builder.append(template.substring(templateStart));

      if (i < args.length) {
         builder.append(" [");
         builder.append(args[i++]);
         while (i < args.length) {
            builder.append(", ");
            builder.append(args[i++]);
         }
         builder.append(']');
      }

      return builder.toString();
   }
}