Fix PigUnit on Windows env

FixHadoopOnWindows.java

package example.pig;

import javassist.CannotCompileException;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.NotFoundException;

public class FixHadoopOnWindows {

    /**
     * Fix the followind Hadoop problem on Windows:
     * 1) mapReduceLayer.Launcher: Backend error message during job submission java.io.IOException: Failed to set permissions of path: \tmp\hadoop-MyUsername\mapred\staging\
     * 2) java.io.IOException: Failed to set permissions of path: bla-bla-bla\.staging to 0700
     */

    public static void runFix() throws NotFoundException, CannotCompileException {
        if( isWindows() ) { // run fix only on Windows
            setUpSystemVariables();
            fixCheckReturnValueMethod();
        }
    }

    // set up correct temporary directory on windows
    private static void setUpSystemVariables() {
        System.getProperties().setProperty("java.io.tmpdir", "D:/TMP/");
    }

    /**
     * org.apache.hadoop.fs.FileUtil#checkReturnValue doesn't work on Windows at all
     * so, let's change method body with Javassist on empty body
     */
    private static void fixCheckReturnValueMethod() throws NotFoundException, CannotCompileException {
        ClassPool cp = new ClassPool(true);
        CtClass ctClass = cp.get("org.apache.hadoop.fs.FileUtil");
        CtMethod ctMethod = ctClass.getDeclaredMethod("checkReturnValue");
        ctMethod.setBody("{  }");
        ctClass.toClass();
    }

    private static boolean isWindows() {
        String OS = System.getProperty("os.name");
        return OS.startsWith("Windows");
    }

    private FixHadoopOnWindows() { }
}