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comparison src/nabble/model/NodeIterator.java @ 0:7ecd1a4ef557

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author Franklin Schmidt <fschmidt@gmail.com>
date Thu, 21 Mar 2019 19:15:52 -0600
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-1:000000000000 0:7ecd1a4ef557
1 package nabble.model;
2
3 import java.util.Iterator;
4 import java.util.NoSuchElementException;
5 import java.util.List;
6 import java.util.ArrayList;
7 import java.util.Collection;
8
9
10 public abstract class NodeIterator<C extends Node> implements Iterator<C>, Iterable<C> {
11 public abstract boolean hasNext();
12 public abstract C next() throws NoSuchElementException;
13 public abstract void close();
14
15 public final void remove() {
16 throw new UnsupportedOperationException();
17 }
18
19 public final Iterator<C> iterator() {
20 return this;
21 }
22
23 public void skip(int n) {
24 while( hasNext() && n-- > 0 ) {
25 next();
26 }
27 }
28
29 // calls close()
30 public final boolean isEmpty() {
31 try {
32 return !hasNext();
33 } finally {
34 close();
35 }
36 }
37
38 public final boolean contains(Node node) {
39 try {
40 while( hasNext() ) {
41 if( next().equals(node) )
42 return true;
43 }
44 return false;
45 } finally {
46 close();
47 }
48 }
49
50 public final void addTo(Collection<Node> col) {
51 while( hasNext() ) {
52 col.add( next() );
53 }
54 close();
55 }
56
57 public List<Node> get(int i,int n) {
58 List<Node> list = new ArrayList<Node>();
59 skip(i);
60 while( hasNext() && n-- > 0 ) {
61 list.add( next() );
62 }
63 close();
64 return list;
65 }
66
67 public List<C> asList() {
68 List<C> list = new ArrayList<C>();
69 while( hasNext()) {
70 list.add( next() );
71 }
72 return list;
73 }
74
75 public static final <T extends Node> NodeIterator<T> empty() {
76 return new NodeIterator<T>() {
77
78 @Override public boolean hasNext() {
79 return false;
80 }
81
82 @Override public T next() throws NoSuchElementException {
83 throw new NoSuchElementException();
84 }
85
86 @Override public void close() {}
87
88 };
89 }
90
91 public static <T extends Node> NodeIterator<T> nodeIterator(final Iterator<T> iter) {
92 return new NodeIterator<T>() {
93
94 @Override public boolean hasNext() {
95 return iter.hasNext();
96 }
97
98 @Override public T next() throws NoSuchElementException {
99 return iter.next();
100 }
101
102 @Override public void close() {}
103
104 };
105 }
106
107 public static <T extends Node> NodeIterator<T> nodeIterator(final List<T> list) {
108 return new NodeIterator<T>() {
109 private Iterator<T> iter = null;
110
111 private Iterator<T> iter() {
112 if( iter == null )
113 iter = list.iterator();
114 return iter;
115 }
116
117 @Override public boolean hasNext() {
118 return iter().hasNext();
119 }
120
121 @Override public T next() throws NoSuchElementException {
122 return iter().next();
123 }
124
125 @Override public void close() {}
126
127 @Override public List<T> asList() {
128 return iter==null ? list : super.asList();
129 }
130
131 };
132 }
133
134 }