source: java/PlatformTools/src/net/oni2/platformtools/applicationinvoker/DotNet.java

package net.oni2.platformtools.applicationinvoker;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.util.Vector;

import net.oni2.platformtools.PlatformInformation;
import net.oni2.platformtools.PlatformInformation.Architecture;
import net.oni2.platformtools.PlatformInformation.Platform;
import net.oni2.platformtools.WinRegistry;
import net.oni2.platformtools.applicationinvoker.ApplicationInvoker;
import net.oni2.platformtools.applicationinvoker.ApplicationInvocationResult;

/**
 * @author Christian Illy
 */
public class DotNet {
        private static File mono = null;
        private static int isInst = -1;

        /**
         * @return is a .NET implementation installed?
         */
        public static boolean isInstalled() {
                if (isInst < 0) {
                        isInst = 0;
                        switch (PlatformInformation.getPlatform()) {
                                case WIN:
                                        try {
                                                int view = WinRegistry.KEY_WOW64_32KEY;
                                                if (PlatformInformation.getArchitecture() == Architecture.AMD64)
                                                        view = WinRegistry.KEY_WOW64_64KEY;

                                                Map<String, String> m = WinRegistry
                                                                .readStringValues(
                                                                                WinRegistry.HKEY_LOCAL_MACHINE,
                                                                                "Software\\Microsoft\\NET Framework Setup\\NDP\\v2.0.50727",
                                                                                view);
                                                isInst = (m != null ? 1 : 0);
                                        } catch (IllegalArgumentException e) {
                                                e.printStackTrace();
                                        } catch (IllegalAccessException e) {
                                                e.printStackTrace();
                                        } catch (InvocationTargetException e) {
                                                e.printStackTrace();
                                        } catch (Exception e) {
                                                if (!e.getMessage()
                                                                .equals("Registry access not supported (not a Windows OS?)."))
                                                        e.printStackTrace();
                                        }
                                        break;
                                case MACOS:
                                case LINUX:
                                        Vector<String> params = new Vector<String>();
                                        params.add("mono");
                                        ApplicationInvocationResult res = null;
                                        try {
                                                res = ApplicationInvoker.executeAndWait(EExeType.OSBINARY, null, new File("which"), params, false);
                                        } catch (IOException e) {
                                                e.printStackTrace();
                                        } catch (ERuntimeNotInstalledException e) {
                                                e.printStackTrace();
                                        }
                                        if (res != null) {
                                                if (res.output.size() > 0) {
                                                        if (res.output.get(0).startsWith("/")
                                                                        && res.output.get(0).endsWith("mono")) {
                                                                isInst = 1;
                                                                mono = new File(res.output.get(0));
                                                        }
                                                }
                                        }
                                        break;
                                default:
                                        isInst = 0;
                        }
                }
                return isInst == 1;
        }

        /**
         * @return Get the .Net runtime executable name
         */
        public static File getRuntimeExe() {
                if (PlatformInformation.getPlatform() != Platform.WIN)
                        return mono;
                return null;
        }

}