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 package clojure.lang;

    12 

    13 import java.io.IOException;

    14 import java.io.NotSerializableException;

    15 import java.util.Iterator;

    16 

    17 public class IteratorSeq extends ASeq{

    18 final Iterator iter;

    19 final State state;

    20 

    21     static class State{

    22 	volatile Object val;

    23 	volatile Object _rest;

    24 }

    25 

    26 public static IteratorSeq create(Iterator iter){

    27 	if(iter.hasNext())

    28 		return new IteratorSeq(iter);

    29 	return null;

    30 }

    31 

    32 IteratorSeq(Iterator iter){

    33 	this.iter = iter;

    34 	state = new State();

    35 	this.state.val = state;

    36 	this.state._rest = state;

    37 }

    38 

    39 IteratorSeq(IPersistentMap meta, Iterator iter, State state){

    40 	super(meta);

    41 	this.iter = iter;

    42 	this.state = state;

    43 }

    44 

    45 public Object first(){

    46 	if(state.val == state)

    47 		synchronized(state)

    48 			{

    49 			if(state.val == state)

    50 				state.val = iter.next();

    51 			}

    52 	return state.val;

    53 }

    54 

    55 public ISeq next(){

    56 	if(state._rest == state)

    57 		synchronized(state)

    58 			{

    59 			if(state._rest == state)

    60 				{

    61 				first();

    62 				state._rest = create(iter);

    63 				}

    64 			}

    65 	return (ISeq) state._rest;

    66 }

    67 

    68 public IteratorSeq withMeta(IPersistentMap meta){

    69 	return new IteratorSeq(meta, iter, state);

    70 }

    71 

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

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

    74 }

    75 }
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
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