%line	%branch
org.apache.jcs.utils.struct.SingleLinkedList$Node	100%	100%

1		package org.apache.jcs.utils.struct;
2
3		/*
4		* Licensed to the Apache Software Foundation (ASF) under one
5		* or more contributor license agreements. See the NOTICE file
6		* distributed with this work for additional information
7		* regarding copyright ownership. The ASF licenses this file
8		* to you under the Apache License, Version 2.0 (the
9		* "License"); you may not use this file except in compliance
10		* with the License. You may obtain a copy of the License at
11		*
12		* http://www.apache.org/licenses/LICENSE-2.0
13		*
14		* Unless required by applicable law or agreed to in writing,
15		* software distributed under the License is distributed on an
16		* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17		* KIND, either express or implied. See the License for the
18		* specific language governing permissions and limitations
19		* under the License.
20		*/
21
22		import org.apache.commons.logging.Log;
23		import org.apache.commons.logging.LogFactory;
24
25		/**
26		* This is an basic thread safe single linked list. It provides very limited functionality. It is
27		* small and fast.
28		* <p>
29		* @author Aaron Smuts
30		*/
31		public class SingleLinkedList
32		{
33		private static final Log log = LogFactory.getLog( SingleLinkedList.class );
34
35		private Object lock = new Object();
36
37		// the head of the queue
38		private Node head = new Node();
39
40		// the end of the queue
41		private Node tail = head;
42
43		private int size = 0;
44
45		/**
46		* Takes the first item off the list.
47		* <p>
48		* @return null if the list is empty.
49		*/
50		public Object takeFirst()
51		{
52		synchronized ( lock )
53		{
54		// wait until there is something to read
55		if ( head == tail )
56		{
57		return null;
58		}
59
60		Node node = head.next;
61
62		Object value = node.payload;
63
64		if ( log.isDebugEnabled() )
65		{
66		log.debug( "head.payload = " + head.payload );
67		log.debug( "node.payload = " + node.payload );
68		}
69
70		// Node becomes the new head (head is always empty)
71
72		node.payload = null;
73		head = node;
74
75		size--;
76		return value;
77		}
78		}
79
80		/**
81		* Adds an item to the end of the list.
82		* <p>
83		* @param payload
84		*/
85		public void addLast( Object payload )
86		{
87		Node newNode = new Node();
88
89		newNode.payload = payload;
90
91		synchronized ( lock )
92		{
93		size++;
94		tail.next = newNode;
95		tail = newNode;
96		}
97		}
98
99		/**
100		* Removes everything.
101		*/
102		public void clear()
103		{
104		synchronized ( lock )
105		{
106		head = tail;
107		size = 0;
108		}
109		}
110
111		/**
112		* The list is composed of nodes.
113		* <p>
114		* @author Aaron Smuts
115		*/
116	82431	private static class Node
117		{
118	41114	Node next = null;
119
120		Object payload;
121		}
122
123		/**
124		* Returns the number of elements in the list.
125		* <p>
126		* @return number of items in the list.
127		*/
128		public int size()
129		{
130		return size;
131		}
132		}

This report is generated by jcoverage, Maven and Maven JCoverage Plugin.