Mercurial > lasercutter

     1 /**

     2  *   Copyright (c) Rich Hickey. All rights reserved.

     3  *   The use and distribution terms for this software are covered by the

     4  *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

     5  *   which can be found in the file epl-v10.html at the root of this distribution.

     6  *   By using this software in any fashion, you are agreeing to be bound by

     7  * 	 the terms of this license.

     8  *   You must not remove this notice, or any other, from this software.

     9  **/

    10 

    11 /* rich Mar 3, 2008 */

    12 

    13 package clojure.lang;

    14 

    15 import java.io.IOException;

    16 import java.io.NotSerializableException;

    17 import java.util.Enumeration;

    18 

    19 public class EnumerationSeq extends ASeq{

    20 final Enumeration iter;

    21 final State state;

    22 

    23     static class State{

    24 	volatile Object val;

    25 	volatile Object _rest;

    26 }

    27 

    28 public static EnumerationSeq create(Enumeration iter){

    29 	if(iter.hasMoreElements())

    30 		return new EnumerationSeq(iter);

    31 	return null;

    32 }

    33 

    34 EnumerationSeq(Enumeration iter){

    35 	this.iter = iter;

    36 	state = new State();

    37 	this.state.val = state;

    38 	this.state._rest = state;

    39 }

    40 

    41 EnumerationSeq(IPersistentMap meta, Enumeration iter, State state){

    42 	super(meta);

    43 	this.iter = iter;

    44 	this.state = state;

    45 }

    46 

    47 public Object first(){

    48 	if(state.val == state)

    49 		synchronized(state)

    50 			{

    51 			if(state.val == state)

    52 				state.val = iter.nextElement();

    53 			}

    54 	return state.val;

    55 }

    56 

    57 public ISeq next(){

    58 	if(state._rest == state)

    59 		synchronized(state)

    60 			{

    61 			if(state._rest == state)

    62 				{

    63 				first();

    64 				state._rest = create(iter);

    65 				}

    66 			}

    67 	return (ISeq) state._rest;

    68 }

    69 

    70 public EnumerationSeq withMeta(IPersistentMap meta){

    71 	return new EnumerationSeq(meta, iter, state);

    72 }

    73 

    74 private void writeObject (java.io.ObjectOutputStream out) throws IOException {

    75     throw new NotSerializableException(getClass().getName());

    76 }

    77 

    78 }
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
parents
children