Index establishment process of lucene4.7 source Research (1)

Directory overall process is still relatively simple, picture borrowing

Directory directory = fsdirectory.open (file);

/**creates an Fsdirectory instance, trying to pick the "best implementation given" the current environment. * The directory returned uses the {@linkNativefslockfactory}. * * <p>currently This returns {@linkMmapdirectory} for most Solaris * and Windows 64-bit JREs, {@linkNiofsdirectory} for other * Non-windows JREs, and {@linkSimplefsdirectory} for other * JREs on Windows.  It is highly recommended so consult the * implementation ' s documentation for your platform before * using this   Method. * * <P><B>NOTE</B>: This method may suddenly change which * implementation are returned from release to release, in * the event that higher performance defaults become * possible; If the precise implementation is important to * your application, please instantiate it directly, * instead. For optimal performance should consider using * {@linkMmapdirectory} on the JVMs bit. * * <p>see <a href= "#subclasses" >above</a>*/   Public StaticFsdirectory Open (File path)throwsIOException {returnOpen (Path,NULL);//Use default lock factory}/**Just like {@link#open (File)}, but allows your to * also specify a custom {@linkLockfactory}. */   Public StaticFsdirectory Open (File path, lockfactory lockfactory)throwsIOException {if((Constants.windows | | Constants.sun_os | |constants.linux)&& Constants.jre_is_64bit &&mmapdirectory.unmap_supported) {      return Newmmapdirectory (path, lockfactory); } Else if(constants.windows) {return Newsimplefsdirectory (path, lockfactory); } Else {      return Newniofsdirectory (path, lockfactory); }  }

Taking Niofsdirectory as an example

 /**   Create a new niofsdirectory for the named   Location.  * *   @param   path the path of the directory *   @param   Lockfactory the lock factory to use , or NULL for the default * ({  @link    @throws   IOException if there is a Low-level I/O error  */ public  Niofsdirectory (File path, lockfactory lockfactory) throws   IOException { super   (path, lockfactory)  ; }

/**Create A new fsdirectory for the named location (ctor for subclasses). * @parampath The path of the directory *@paramLockfactory the Lock factory to use, or NULL for the default * ({@linknativefslockfactory}); * @throwsIOException If there is a low-level I/O error*/  protectedFsdirectory (File path, lockfactory lockfactory)throwsIOException {//new ctors use always nativefslockfactory as default:    if(Lockfactory = =NULL) {lockfactory=Newnativefslockfactory (); } directory=Getcanonicalpath (path);//Get Path absolute pathif(Directory.Exists () &&!directory.isdirectory ())Throw NewNosuchdirectoryexception ("file" + directory + "' exists but isn't a directory"); Setlockfactory (lockfactory);//Set Lock Factory}

  /**    * Create A nativefslockfactory instance, with null (unset)   * Lock directory. When your pass this factory to a {@link  fsdirectory}   * Subclass, the lock directory is automatically Set to the   * directory itself. Be sure to create one instance for each directory   * your create!    */   Public nativefslockfactory () {    thisnull);//Factory not set path  }

@Override Public voidSetlockfactory (Lockfactory lockfactory)throwsIOException {Super. Setlockfactory (lockfactory); //for filesystem based Lockfactory, delete the Lockprefix, if the locks is placed//In index dir. If No index dir is given, set ourselves    if(lockfactoryinstanceoffslockfactory) {      FinalFslockfactory LF =(fslockfactory) lockfactory; FinalFile dir =Lf.getlockdir ();//Because (File) null, so dir is null//If the lock factory have no Lockdir set, use the This directory as Lockdir      if(dir = =NULL) {lf.setlockdir (directory);//Use the directory lf.setlockprefix that we set up (NULL); } Else if(Dir.getcanonicalpath (). Equals (Directory.getcanonicalpath ())) {Lf.setlockprefix (NULL); }    }  }

The entire open process is in fact setlockdir () in a simple positioning lockfactory, and set lockid

BaseDirectory

@Override    Public String toString () {    return'@'"  lockfactory=  " + getlockfactory ();  }

Index establishment process of lucene4.7 source Research (1)