field.java

《移动Agent技术》一书的所有章节源代码。

     * Get the value of a field as a int on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the field value cannot be
     *              converted to the return type by a widening conversion.
     * @see       Field#get
     */
    public native int getInt(Object obj)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Get the value of a field as a long on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the field value cannot be
     *              converted to the return type by a widening conversion.
     * @see       Field#get
     */
    public native long getLong(Object obj)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Get the value of a field as a float on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the field value cannot be
     *              converted to the return type by a widening conversion.
     * @see       Field#get
     */
    public native float getFloat(Object obj)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Get the value of a field as a double on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the field value cannot be
     *              converted to the return type by a widening conversion.
     * @see       Field#get
     */
    public native double getDouble(Object obj)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Sets the field represented by this Field object on the
     * specified object argument to the specified new value. The new
     * value is automatically unwrapped if the underlying field has a
     * primitive type.
     *
     * <p>The operation proceeds as follows:
     *
     * <p>If the underlying field is static, the object argument is
     * ignored; it may be null.
     *
     * <p>Otherwise the underlying field is an instance field.  If the
     * specified object argument is null, the method throws a
     * NullPointerException.  If the specified object argument is not
     * an instance of the class or interface declaring the underlying
     * field, the method throws an IllegalArgumentException.
     *
     * <p>If this Field object enforces Java language access control, and
     * the underlying field is inaccessible, the method throws an
     * IllegalAccessException.
     *
     * <p>If the underlying field is final, the method throws an
     * IllegalAccessException.
     *
     * <p>If the underlying field is of a primitive type, an unwrapping
     * conversion is attempted to convert the new value to a value of
     * a primitive type.  If this attempt fails, the method throws an
     * IllegalArgumentException.
     *
     * <p>If, after possible unwrapping, the new value cannot be
     * converted to the type of the underlying field by an identity or
     * widening conversion, the method throws an
     * IllegalArgumentException.
     *
     * <p>The field is set to the possibly unwrapped and widened new value.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null.
     */
    public native void set(Object obj, Object value)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a boolean on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setBoolean(Object obj, boolean z)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a byte on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setByte(Object obj, byte b)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a char on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setChar(Object obj, char c)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a short on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setShort(Object obj, short s)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as an int on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setInt(Object obj, int i)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a long on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setLong(Object obj, long l)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a float on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setFloat(Object obj, float f)
	throws IllegalArgumentException, IllegalAccessException;

    /**
     * Set the value of a field as a double on specified object.
     *
     * @exception IllegalAccessException    if the underlying constructor
     *              is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field, or if an unwrapping conversion fails.
     * @see       Field#set
     */
    public native void setDouble(Object obj, double d)
	throws IllegalArgumentException, IllegalAccessException;

    /*
     * Utility routine to paper over array type names
     */
    static String getTypeName(Class type) {
	if (type.isArray()) {
	    try {
		Class cl = type;
		int dimensions = 0;
		while (cl.isArray()) {
		    dimensions++;
		    cl = cl.getComponentType();
		}
		StringBuffer sb = new StringBuffer();
		sb.append(cl.getName());
		for (int i = 0; i < dimensions; i++) {
		    sb.append("[]");
		}
		return sb.toString();
	    } catch (Throwable e) { /*FALLTHRU*/ }
	}
	return type.getName();
    }

}