Java File Find findExecutableOnPath(String executableName)

Description

Tries to find the given executable on the path

License

Open Source License

Declaration

public static File findExecutableOnPath(String executableName) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.io.File;

public class Main {
    /**/*from ww w  .j a v  a  2s  .  c  o m*/
     * Tries to find the given executable on the path
     */
    public static File findExecutableOnPath(String executableName) {
        //Check, did they specify something we can resolve?
        File fullyQualifiedExecutable = null;

        fullyQualifiedExecutable = new File(expandPath(executableName));
        //if(1 > 0)
        //    return new File(executableName);
        if (fullyQualifiedExecutable.isFile()) {
            return fullyQualifiedExecutable;
        }
        //Otherwise, keep looking
        String systemPath = System.getenv("PATH");
        String[] pathDirs = systemPath.split(File.pathSeparator);

        for (String pathDir : pathDirs) {
            fullyQualifiedExecutable = new File(pathDir, executableName);
            if (fullyQualifiedExecutable.isFile()) {
                return fullyQualifiedExecutable;
            }
        }
        //We failed to find it
        return null;
    }

    /**
     * Tries to resolve any relative paths/symlinks on a given path
     */
    public static String expandPath(String path) {
        if (System.getProperty("os.name").toLowerCase().indexOf("win") == 0) {
            String exp = path;
            try {
                Process shellExec = Runtime.getRuntime().exec("cmd.exe /C echo " + exp);

                java.io.BufferedReader reader = new java.io.BufferedReader(
                        new java.io.InputStreamReader(shellExec.getInputStream()));
                String expandedPath = reader.readLine();

                // Only return a new value if expansion worked.
                // We're reading from stdin. If there was a problem, it was written
                // to stderr and our result will be null.
                if (expandedPath != null) {
                    exp = expandedPath;
                }
            } catch (java.io.IOException ex) {
                // Just consider it unexpandable and return original path.
                ex.printStackTrace();
                System.out.println("WARNING: Failed to expand path '" + path + "'");
            }
            File f = new File(exp);
            path = f.getAbsolutePath();
        } else //We're probably on a posix system....
        {
            try {
                String command = "ls -d " + path;
                Process shellExec = Runtime.getRuntime().exec(new String[] { "bash", "-c", command });

                java.io.BufferedReader reader = new java.io.BufferedReader(
                        new java.io.InputStreamReader(shellExec.getInputStream()));
                String expandedPath = reader.readLine();

                // Only return a new value if expansion worked.
                // We're reading from stdin. If there was a problem, it was written
                // to stderr and our result will be null.
                if (expandedPath != null) {
                    path = expandedPath;
                }
            } catch (java.io.IOException ex) {
                // Just consider it unexpandable and return original path.
                System.out.println(
                        "WARNING: Failed to expand path '" + path + "' - probably due to a lack of unix...");
            }
        }
        return path;
    }
}

Related

1. findExecutableInPath(String exec)
2. findExecutableInSystemPath(String executable)
3. findExecutableLocation(String executableName)
4. findExecutableOnPath(String executable)
5. findExecutableOnPath(String executableName)
6. findJavaFiles(File dir, Collection filenames)
7. findJavaFiles(File folder)