subdate.java

mysql集群

/*****************************************************************************
      SQLJEP - Java SQL Expression Parser 0.2
      November 1 2006
         (c) Copyright 2006, Alexey Gaidukov
      SQLJEP Author: Alexey Gaidukov

      SQLJEP is based on JEP 2.24 (http://www.singularsys.com/jep/)
           (c) Copyright 2002, Nathan Funk
 
      See LICENSE.txt for license information.
*****************************************************************************/

package com.meidusa.amoeba.sqljep.function;

import java.sql.Timestamp;

import com.meidusa.amoeba.sqljep.function.PostfixCommand;
import com.meidusa.amoeba.sqljep.ASTFunNode;
import com.meidusa.amoeba.sqljep.JepRuntime;
import com.meidusa.amoeba.sqljep.ParseException;

public class SubDate extends PostfixCommand {
	final public int getNumberOfParameters() {
		return 2;
	}
	
	/**
	 * Calculates the result of applying the "+" operator to the arguments from
	 * the stack and pushes it back on the stack.
	 */
	public Comparable<?>[] evaluate(ASTFunNode node, JepRuntime runtime) throws ParseException {
		node.childrenAccept(runtime.ev, null);
		Comparable<?>  param2 = runtime.stack.pop();
		Comparable<?>  param1 = runtime.stack.pop();
		return new Comparable<?>[]{param1,param2};
	}


	public static java.util.Date subDate(Comparable<?>  param1, Comparable<?>  param2) throws ParseException {
		if (param1 == null || param2 == null) {
			return null;
		}
		try {
			int days = (int)getDouble(param2);
			if (param1 instanceof Timestamp) {
				Timestamp d = (Timestamp)param1;
				return new Timestamp(d.getTime()-days*86400000);
			}
			else if (param1 instanceof java.sql.Date) {
				java.sql.Date d = (java.sql.Date)param1;
				return new java.sql.Date(d.getTime()-days*86400000);
			} else {
				throw new ParseException();
			}
		} catch (ParseException e) {
			throw new ParseException(WRONG_TYPE+"  subDate("+param1.getClass()+","+param2.getClass()+")");
		}
	}

	public Comparable<?> getResult(Comparable<?>... comparables)
			throws ParseException {
		return subDate(comparables[0],comparables[1]);
	}
}