ModeUtil.java

package railo.commons.io;

import java.io.IOException;

public final class ModeUtil {

    public static final int PERM_READ = 04; 
    public static final int PERM_WRITE = 02; 
    public static final int PERM_EXECUTE = 01;

    public static final int ROLE_OWNER = 0100; 
    public static final int ROLE_GROUP = 010; 
    public static final int ROLE_WORLD = 01;


    /** 
     * translate a string mode (777 or drwxrwxrwx to a octal value) 
     * @param strMode 
     * @return 
     */ 
    public static int toOctalMode(String strMode) throws IOException { 
            strMode=strMode.trim().toLowerCase(); 
            if(strMode.length()==9 || strMode.length()==10) 
            	return _toOctalMode(strMode);
            if(strMode.length()<=4 && strMode.length()>0) 
            	return Integer.parseInt(strMode,8); 
            throw new IOException("can't translate ["+strMode+"] to a mode value"); 
    }
    
    private static int _toOctalMode(String strMode) {
		int index;
		strMode=strMode.trim().toLowerCase();
		if(strMode.length()==9)index=0;
		else index=1;
		
		int mode=0;
		
		// owner
		if("r".equals(strMode.substring(index++,index)))mode+=0400;
		if("w".equals(strMode.substring(index++,index)))mode+=0200;
		if("x".equals(strMode.substring(index++,index)))mode+=0100;
		// group
		if("r".equals(strMode.substring(index++,index)))mode+=040;
		if("w".equals(strMode.substring(index++,index)))mode+=020;
		if("x".equals(strMode.substring(index++,index)))mode+=010;
		// world
		if("r".equals(strMode.substring(index++,index)))mode+=04;
		if("w".equals(strMode.substring(index++,index)))mode+=02;
		if("x".equals(strMode.substring(index++,index)))mode+=01;		
		return mode;
	}

    /** 
     * translate a octal mode value (73) to a string representation ("111") 
     * @param strMode 
     * @return 
     */ 
    public static String toStringMode(int octalMode) { 
            String str = Integer.toString(octalMode,8); 
            while(str.length()<3)str="0"+str;
            return str;
    } 
    
    /** 
     * update a string mode with a other (111+222=333 or 333+111=333 or 113+202=313) 
     * @param existing 
     * @param update 
     * @return 
     * @throws IOException 
     */ 
    public static String updateMode(String existing, String update) throws IOException { 
            return toStringMode(updateMode(toOctalMode(existing), toOctalMode(update))); 
    }

    /** 
     * update octal mode with a other 
     * @param existingOctal 
     * @param updateOctal 
     * @return 
     */ 
    public static int updateMode(int existingOctal, int updateOctal) { 
            int tmp=existingOctal&updateOctal; 
            return (existingOctal-tmp)+updateOctal; 
    } 
    
    /** 
     * check mode for a specific permission 
     * @param role 
     * @param permission 
     * @param mode 
     * @return 
     */ 
    public static boolean hasPermission(int role, int permission, int mode) { 
            return (mode&(role*permission))>0; 
    } 
    
    /** check if mode is readable for owner 
     * @param octalMode 
     * @return 
     */ 
    public static boolean isReadable(int octalMode) { 
            return hasPermission(ROLE_OWNER,PERM_READ, octalMode); 
    }

    /** check if mode is writeable for owner 
     * @param octalMode 
     * @return 
     */ 
    public static boolean isWritable(int octalMode) { 
            return hasPermission(ROLE_OWNER,PERM_WRITE, octalMode); 
    }

    /** check if mode is executable for owner 
     * @param octalMode 
     * @return 
     */ 
    public static boolean isExecutable(int octalMode) { 
            return hasPermission(ROLE_OWNER,PERM_EXECUTE, octalMode); 
    } 
    
    public static int setReadable(int octalMode, boolean value) { 
            int tmp=octalMode&0444; 
            if(value)return (octalMode-tmp)+0444; 
            return octalMode-tmp; 
    }

    public static int setWritable(int octalMode, boolean value) { 
            int tmp=octalMode&0222; 
            if(value)return (octalMode-tmp)+0222; 
            return octalMode-tmp; 
    }

    public static int setExecutable(int octalMode, boolean value) { 
            int tmp=octalMode&0111; 
            if(value)return (octalMode-tmp)+0111; 
            return octalMode-tmp; 
    } 
    
    public static void main(String[] args) throws IOException {
		System.out.println(toStringMode(toOctalMode("--xrwxrwx")));
		System.out.println(toStringMode(Integer.parseInt("0777",8)));
	}
}