lastmodified.java

JAVA 数学程序库 提供常规的数值计算程序包

package jmathlib.toolbox.io;

import jmathlib.core.tokens.*;
import jmathlib.core.tokens.numbertokens.DoubleNumberToken;
import jmathlib.core.functions.ExternalFunction;
import java.io.*;

public class lastmodified extends ExternalFunction
{
	public OperandToken evaluate(Token[] operands)
	{

        if (getNArgIn(operands) != 1)
			throwMathLibException("lastmodified: number of arguments != 1");

		if (!(operands[0] instanceof CharToken)) 
            throwMathLibException("lastmodified: argument must be a string");

        String name = ((CharToken)operands[0]).toString();

		try
		{
			File file = new File(getWorkingDirectory(), name);

            // check if file exists in current workspace
            if (!file.exists())
                throwMathLibException("lastmodified: file does not exist");
            
            // return date of last modification: seconds since 1970
            //   -> may need some better return value :-)
			return new DoubleNumberToken(file.lastModified());
		}
		catch (Exception e)
		{
            throwMathLibException("lastmodified: file does not exist");
		}		    

		return null;		

	} // end eval
}

/*
@GROUP
IO
@SYNTAX
lastmodified(filename)
@DOC
Returns the date of the last modification of given file
@EXAMPLES
<programlisting>
lastmodified("barfoo.txt");
</programlisting>
@NOTES
@SEE
cd, createnewfile, dir, exist, mkdir, rmdir, delete, isfile, isdirectory, ishidden
*/