JavaFinder.java

package net.ftb.util.winreg;

import java.io.File;
import java.util.Collections;
import java.util.List;

/**
 * Java Finder by petrucio@stackoverflow(828681) is licensed under a Creative Commons Attribution 3.0 Unported License.
 * Needs WinRegistry.java. Get it at: http://stackoverflow.com/questions/62289/read-write-to-windows-registry-using-java
 *
 * JavaFinder - Windows-specific classes to search for all installed versions of java on this system
 * Author: petrucio@stackoverflow (828681)
 *****************************************************************************/

import com.google.common.collect.Lists;

import net.ftb.log.Logger;
import net.ftb.util.OSUtils;
import net.ftb.util.OSUtils.OS;

/**
 * Windows-specific java versions finder
 *****************************************************************************/
public class JavaFinder
{
	/**
	 * @return: A list of javaExec paths found under this registry key (rooted at HKEY_LOCAL_MACHINE)
	 * @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app)
	 *        or WinRegistry.KEY_WOW64_32KEY to force access to 32-bit registry view,
	 *        or WinRegistry.KEY_WOW64_64KEY to force access to 64-bit registry view
	 * @param previous: Insert all entries from this list at the beggining of the results
	 *************************************************************************/
	private static List<String> searchRegistry (String key, int wow64, final List<String> previous)
	{
		List<String> result = previous;
		try
		{
			List<String> entries = WinRegistry.readStringSubKeys(WinRegistry.HKEY_LOCAL_MACHINE, key, wow64);
			for(int i = 0; entries != null && i < entries.size(); i++)
			{
				String val = WinRegistry.readString(WinRegistry.HKEY_LOCAL_MACHINE, key + "\\" + entries.get(i), "JavaHome", wow64);
				if (!result.contains(val + "\\bin\\java.exe"))
				{
					result.add(val + "\\bin\\java.exe");
				}
			}
		}
		catch (Throwable t)
		{
			Logger.logError("Error Searching windows registry for java versions", t);
		}
		return result;
	}

	/**
	 * @return: A list of JavaInfo with informations about all javas installed on this machine
	 *          Searches and returns results in this order:
	 *          HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment (32-bits view)
	 *          HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment (64-bits view)
	 *          HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Development Kit (32-bits view)
	 *          HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Development Kit (64-bits view)
	 *          WINDIR\system32
	 *          WINDIR\SysWOW64
	 ****************************************************************************/
	public static List<JavaInfo> findJavas ()
	{
		if (OSUtils.getCurrentOS() == OS.MACOSX)
		{
			return findMacJavas();
		}

		if (OSUtils.getCurrentOS() == OS.WINDOWS)
		{
			return findWinJavas();
		}

		return Lists.newArrayList();
	}

	protected static List<JavaInfo> findWinJavas ()
	{
		List<String> javaExecs = Lists.newArrayList();

		javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Runtime Environment", WinRegistry.KEY_WOW64_32KEY, javaExecs);
		javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Runtime Environment", WinRegistry.KEY_WOW64_64KEY, javaExecs);
		javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Development Kit", WinRegistry.KEY_WOW64_32KEY, javaExecs);
		javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Development Kit", WinRegistry.KEY_WOW64_64KEY, javaExecs);

		javaExecs.add(System.getenv("WINDIR") + "\\system32\\java.exe");
		javaExecs.add(System.getenv("WINDIR") + "\\SysWOW64\\java.exe");
		javaExecs.add(System.getProperty("java.home") + "\\bin\\java.exe");

		List<JavaInfo> result = Lists.newArrayList();
		for(String javaPath : javaExecs)
		{
			File javaFile = new File(javaPath);
			if (!javaFile.exists() || !javaFile.canExecute() || JavaInfo.getJavaInfo(javaPath) == null)
			{
				continue;
			}
			try
			{
				result.add(JavaInfo.getJavaInfo(javaPath));
			}
			catch (Exception e)
			{
				Logger.logDebug("Error while adding JavaInfo", e);
			}
		}
		return result;
	}

	protected static String getMacJavaPath (String javaVersion)
	{
		String versionInfo;

		versionInfo = RuntimeStreamer.execute(new String[]
			{"/usr/libexec/java_home", "-v " + javaVersion});

		// Unable to find any JVMs matching version "1.7"
		if (versionInfo.contains("version \"" + javaVersion + "\""))
		{
			return null;
		}

		return versionInfo.trim();
	}

	protected static List<JavaInfo> findMacJavas ()
	{
		List<String> javaExecs = Lists.newArrayList();
		String javaVersion;

		javaVersion = getMacJavaPath("1.6");
		if (javaVersion != null)
		{
			javaExecs.add(javaVersion + "/bin/java");
		}

		javaVersion = getMacJavaPath("1.7");
		if (javaVersion != null)
		{
			javaExecs.add(javaVersion + "/bin/java");
		}

		javaVersion = getMacJavaPath("1.8");
		if (javaVersion != null)
		{
			javaExecs.add(javaVersion + "/bin/java");
		}

		javaExecs.add("/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java");
		javaExecs.add(System.getProperty("java.home") + "/bin/java");

		List<JavaInfo> result = Lists.newArrayList();
		for(String javaPath : javaExecs)
		{
			File javaFile = new File(javaPath);
			if (!javaFile.exists() || !javaFile.canExecute() || JavaInfo.getJavaInfo(javaPath) == null)
			{
				continue;
			}

			try
			{
				result.add(JavaInfo.getJavaInfo(javaPath));
			}
			catch (Exception e)
			{
				Logger.logDebug("Error while adding JavaInfo", e);
			}
		}
		return result;
	}

	/**
	 * @return: The path to a java.exe that has the same bitness as the OS
	 *          (or null if no matching java is found)
	 ****************************************************************************/
	public static String getOSBitnessJava ()
	{
		boolean isOS64 = OSUtils.is64BitWindows();

		List<JavaInfo> javas = JavaFinder.findJavas();
		for(JavaInfo java : javas)
		{
			if (java.is64bits == isOS64)
			{
				return java.path;
			}
		}
		return null;
	}

	private static JavaInfo preferred;

	/**
	 * Standalone testing - lists all Javas in the system
	 ****************************************************************************/
	public static JavaInfo parseJavaVersion ()
	{
		if (preferred == null)
		{
			List<JavaInfo> javas = JavaFinder.findJavas();
			Collections.sort(javas, JavaInfo.PREFERRED_SORTING);
			List<JavaInfo> java32 = Lists.newArrayList();
			List<JavaInfo> java64 = Lists.newArrayList();

			Logger.logInfo("The FTB Launcher has found the following Java versions installed:");
			for(JavaInfo java : javas)
			{
				Logger.logInfo(java.toString());

				if (preferred == null && java != null)
				{
					preferred = java;
				}
				if (java.is64bits)
				{
					java64.add(java);
				}
				else
				{
					java32.add(java);
				}

			}

			if (java64.size() > 0)
			{
				for(JavaInfo aJava64 : java64)
				{
					if (!preferred.is64bits || preferred.isOlder(aJava64))
					{
						preferred = aJava64;
					}
				}
			}
			if (java32.size() > 0)
			{
				for(JavaInfo aJava32 : java32)
				{
					if (!preferred.is64bits && preferred.isOlder(aJava32))
					{
						preferred = aJava32;
					}
				}
			}
			Logger.logInfo("Preferred: " + String.valueOf(preferred));
		}

		if (preferred != null)
		{
			return preferred;
		}
		else
		{
			Logger.logError("No Java versions found!");
			return null;
		}
	}
}