Comparative.java

package com.meidusa.amoeba.sqljep.function;

import java.util.Comparator;

@SuppressWarnings("unchecked")
public class Comparative implements Comparable ,Cloneable{
	
	public static final int GreaterThan = 1;
	public static final int GreaterThanOrEqual = 2;
	public static final int Equivalent = 3;
	public static final int Like = 4;
	public static final int NotLike = 5;
	public static final int NotEquivalent = 6;
	public static final int LessThan = 7;
	public static final int LessThanOrEqual = 8;
	
	
	/**
	 * 表达式取反
	 * @param function
	 * @return
	 */
	public static int reverseComparison(int function){
		return 9-function;
	}
	
	/**
	 * 表达式前后位置调换的时候
	 * @param function
	 * @return
	 */
	public static int exchangeComparison(int function){
		if(function == GreaterThan){
			return LessThan;
		}else if(function == GreaterThanOrEqual){
			return LessThanOrEqual;
		}else if(function == LessThan){
			return GreaterThan;
		} if(function == LessThanOrEqual){
			return GreaterThanOrEqual;
		}else{
			return function;
		}
	}
	
	private Comparable value;
	private int comparison;
	protected Comparative(){
	}

	public Comparative(int function,Comparable value){
		this.comparison = function;
		this.value = value;
	}
	
	public Comparable getValue(){
		return value;
	}
	
	public void setComparison(int function){
		this.comparison = function;
	}
	
	public static String getComparisonName(int function){
		if(function == Equivalent){
			return "=";
		}else if(function == GreaterThan){
			return ">";
		}else if(function == GreaterThanOrEqual){
			return ">=";
		}else if(function == LessThanOrEqual){
			return "<=";
		}else if(function == LessThan){
			return "<";
		}else if(function == NotEquivalent){
			return "<>";
		}else if(function == Like){
			return "LIKE";
		}else if(function == NotLike){
			return "NOT LIKE";
		}else{
			return null;
		}
	}
	
	public static int getComparisonByIdent(String ident){
		if("=".equals(ident)){
			return Equivalent;
		}else if(">".equals(ident)){
			return GreaterThan;
		}else if(">=".equals(ident)){
			return GreaterThanOrEqual;
		}else if("<=".equals(ident)){
			return LessThanOrEqual;
		}else if("<".equals(ident)){
			return LessThan;
		}else if("!=".equals(ident)){
			return NotEquivalent;
		}else if("<>".equals(ident)){
			return NotEquivalent;
		}else if("like".equalsIgnoreCase(ident)){
			return Like;
		}else{
			return -1;
		}
	}
	
	public int getComparison(){
		return comparison;
	}
	
	public void setValue(Comparable value){
		this.value = value;
	}
	
	public int compareTo(Object o) {
		if(o instanceof Comparative){
			Comparative other = (Comparative)o;
			return this.getValue().compareTo(other.getValue());
		}else if(o instanceof Comparable){
			return this.getValue().compareTo(o);
		}
		return -1;
	}
	
	public boolean intersect(int function,Comparable other,Comparator comparator){
		return Intersector.intersect(function,other,this.comparison,this.getValue(),comparator);
	}
	
	public boolean intersect(Comparative other,Comparator comparator){
		return other.intersect(this.comparison, this.getValue(), comparator);
	}
	
	public String toString(){
		return getComparisonName(this.comparison)+this.value;
	}
	
	public Object clone(){
		return new Comparative(this.comparison,this.value);
	}
}