array.java

gcc的组建

  public static int getInt(Object array, int index)
  {
    if (array instanceof int[])
      return ((int[]) array)[index];
    if (array instanceof char[])
      return ((char[]) array)[index];
    return getShort(array, index);
  }

  /**
   * Gets an element of a long array.
   *
   * @param array the array to access
   * @param index the array index to access
   * @return the long element at <code>array[index]</code>
   * @throws IllegalArgumentException  if <code>array</code> is not a byte,
   *         char, short, int, or long array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #get(Object, int)
   */
  public static long getLong(Object array, int index)
  {
    if (array instanceof long[])
      return ((long[]) array)[index];
    return getInt(array, index);
  }

  /**
   * Gets an element of a float array.
   *
   * @param array the array to access
   * @param index the array index to access
   * @return the float element at <code>array[index]</code>
   * @throws IllegalArgumentException  if <code>array</code> is not a byte,
   *         char, short, int, long, or float array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #get(Object, int)
   */
  public static float getFloat(Object array, int index)
  {
    if (array instanceof float[])
      return ((float[]) array)[index];
    return getLong(array, index);
  }

  /**
   * Gets an element of a double array.
   *
   * @param array the array to access
   * @param index the array index to access
   * @return the double element at <code>array[index]</code>
   * @throws IllegalArgumentException  if <code>array</code> is not a byte,
   *         char, short, int, long, float, or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #get(Object, int)
   */
  public static double getDouble(Object array, int index)
  {
    if (array instanceof double[])
      return ((double[]) array)[index];
    return getFloat(array, index);
  }

  /**
   * Sets an element of an array. If the array is primitive, then the new
   * value is unwrapped and widened.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not an array,
   *         or the array is primitive and unwrapping value fails, or the
   *         value is not assignable to the array component type
   * @throws NullPointerException if array is null, or if array is primitive
   *         and value is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #setBoolean(Object, int, boolean)
   * @see #setByte(Object, int, byte)
   * @see #setChar(Object, int, char)
   * @see #setShort(Object, int, short)
   * @see #setInt(Object, int, int)
   * @see #setLong(Object, int, long)
   * @see #setFloat(Object, int, float)
   * @see #setDouble(Object, int, double)
   */
  public static void set(Object array, int index, Object value)
  {
    if (array instanceof Object[])
      {
	// Too bad the API won't let us throw the easier ArrayStoreException!
	if (value != null
	    && ! array.getClass().getComponentType().isInstance(value))
	  throw new IllegalArgumentException();
	((Object[]) array)[index] = value;
      }
    else if (value instanceof Byte)
      setByte(array, index, ((Byte) value).byteValue());
    else if (value instanceof Short)
      setShort(array, index, ((Short) value).shortValue());
    else if (value instanceof Integer)
      setInt(array, index, ((Integer) value).intValue());
    else if (value instanceof Long)
      setLong(array, index, ((Long) value).longValue());
    else if (value instanceof Float)
      setFloat(array, index, ((Float) value).floatValue());
    else if (value instanceof Double)
      setDouble(array, index, ((Double) value).doubleValue());
    else if (value instanceof Character)
      setChar(array, index, ((Character) value).charValue());
    else if (value instanceof Boolean)
      setBoolean(array, index, ((Boolean) value).booleanValue());
    else if (array == null)
      throw new NullPointerException();
    else
      throw new IllegalArgumentException();
  }

  /**
   * Sets an element of a boolean array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a boolean
   *         array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setBoolean(Object array, int index, boolean value)
  {
    if (array instanceof boolean[])
      ((boolean[]) array)[index] = value;
    else if (array == null)
      throw new NullPointerException();
    else
      throw new IllegalArgumentException();
  }

  /**
   * Sets an element of a byte array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a byte,
   *         short, int, long, float, or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setByte(Object array, int index, byte value)
  {
    if (array instanceof byte[])
      ((byte[]) array)[index] = value;
    else
      setShort(array, index, value);
  }

  /**
   * Sets an element of a char array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a char,
   *         int, long, float, or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setChar(Object array, int index, char value)
  {
    if (array instanceof char[])
      ((char[]) array)[index] = value;
    else
      setInt(array, index, value);
  }

  /**
   * Sets an element of a short array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a short,
   *         int, long, float, or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setShort(Object array, int index, short value)
  {
    if (array instanceof short[])
      ((short[]) array)[index] = value;
    else
      setInt(array, index, value);
  }

  /**
   * Sets an element of an int array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not an int,
   *         long, float, or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setInt(Object array, int index, int value)
  {
    if (array instanceof int[])
      ((int[]) array)[index] = value;
    else
      setLong(array, index, value);
  }

  /**
   * Sets an element of a long array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a long,
   *         float, or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setLong(Object array, int index, long value)
  {
    if (array instanceof long[])
      ((long[]) array)[index] = value;
    else
      setFloat(array, index, value);
  }

  /**
   * Sets an element of a float array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a float
   *         or double array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setFloat(Object array, int index, float value)
  {
    if (array instanceof float[])
      ((float[]) array)[index] = value;
    else
      setDouble(array, index, value);
  }

  /**
   * Sets an element of a double array.
   *
   * @param array the array to set a value of
   * @param index the array index to set the value to
   * @param value the value to set
   * @throws IllegalArgumentException if <code>array</code> is not a double
   *         array
   * @throws NullPointerException if <code>array</code> is null
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
   *         bounds
   * @see #set(Object, int, Object)
   */
  public static void setDouble(Object array, int index, double value)
  {
    if (array instanceof double[])
      ((double[]) array)[index] = value;
    else if (array == null)
      throw new NullPointerException();
    else
      throw new IllegalArgumentException();
  }

  /**
   * Dynamically and recursively create a multi-dimensioned array of objects.
   *
   * @param type guaranteed to be a valid object type
   * @param dimensions the dimensions of the array
   * @param index index of the current dimension to build
   * @return the new multi-dimensioned array
   * @throws NegativeArraySizeException if any entry of dimensions is negative
   * @throws OutOfMemoryError if memory allocation fails
   */
  // This would be faster if implemented natively, using the multianewarray
  // bytecode instead of this recursive call
  private static Object createMultiArray(Class type, int[] dimensions,
                                         int index)
  {
    if (index == 0)
      return newInstance(type, dimensions[0]);

    Object toAdd = createMultiArray(type, dimensions, index - 1);
    Class thisType = toAdd.getClass();
    Object[] retval
      = (Object[]) createObjectArray(thisType, dimensions[index]);
    if (dimensions[index] > 0)
      retval[0] = toAdd;
    int i = dimensions[index];
    while (--i > 0)
      retval[i] = createMultiArray(type, dimensions, index - 1);
    return retval;
  }

  /**
   * Dynamically create an array of objects.
   *
   * @param type guaranteed to be a valid object type
   * @param dim the length of the array
   * @return the new array
   * @throws NegativeArraySizeException if dim is negative
   * @throws OutOfMemoryError if memory allocation fails
   */
  private static native Object createObjectArray(Class type, int dim);
}