Checkstyle 可寻找：·不能使用的或者多余的输入 ·空格更好的地方不使用跳格符

				//Tested with BCEL-5.1
				//http://jakarta.apache.org/builds/jakarta-bcel/release/v5.1/
				
				package com.puppycrawl.tools.checkstyle.bcel;
				
				import java.util.Set;
				
				/**
				 * Object set visitor for a general set.
				 * @author Rick Giles
				 */
				public interface IObjectSetVisitor
				{
				    /**
				     * Visit a set itself.
				     * @param aSet the set.
				     */
				    void visitSet(Set aSet);
				
				    /**
				     * Finish the visit of a set.
				     * @param aSet the set.
				     */
				    void leaveSet(Set aSet);
				
				    /**
				     * Visit an object. Normally this is an object of the set.
				     * @param aObject the object.
				     */
				    void visitObject(Object aObject);
				
				    /**
				     * Finish the visit an object. Normally this is an object of the set.
				     * @param aObject the object.
				     */
				    void leaveObject(Object aObject);
				}