001    /*
002     * Copyright (C) 2008-2010 by Holger Arndt
003     *
004     * This file is part of the Universal Java Matrix Package (UJMP).
005     * See the NOTICE file distributed with this work for additional
006     * information regarding copyright ownership and licensing.
007     *
008     * UJMP is free software; you can redistribute it and/or modify
009     * it under the terms of the GNU Lesser General Public License as
010     * published by the Free Software Foundation; either version 2
011     * of the License, or (at your option) any later version.
012     *
013     * UJMP is distributed in the hope that it will be useful,
014     * but WITHOUT ANY WARRANTY; without even the implied warranty of
015     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
016     * GNU Lesser General Public License for more details.
017     *
018     * You should have received a copy of the GNU Lesser General Public
019     * License along with UJMP; if not, write to the
020     * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
021     * Boston, MA  02110-1301  USA
022     */
023    
024    package org.ujmp.core.collections;
025    
026    import java.io.Serializable;
027    import java.util.Collection;
028    import java.util.Iterator;
029    import java.util.List;
030    import java.util.ListIterator;
031    
032    public class RingBufferList<A> implements List<A>, Serializable {
033            private static final long serialVersionUID = 7887830184838493458L;
034    
035            private int start = -1;
036    
037            private int end = -1;
038    
039            private Object values[];
040    
041            public RingBufferList() {
042                    this(10);
043            }
044    
045            public RingBufferList(int maximumSize) {
046                    values = new Object[maximumSize];
047            }
048    
049            public int maxSize() {
050                    return values.length;
051            }
052    
053            public boolean add(A a) {
054                    if (end >= 0) {
055                            end++;
056                            if (end >= values.length) {
057                                    end = 0;
058                            }
059                            if (end == start) {
060                                    start++;
061                            }
062                            if (start >= values.length) {
063                                    start = 0;
064                            }
065                    } else {
066                            start = 0;
067                            end = 0;
068                    }
069                    values[end] = a;
070                    return true;
071            }
072    
073            public int size() {
074                    if (end < 0) {
075                            return 0;
076                    }
077                    return end < start ? values.length : end - start + 1;
078            }
079    
080            
081            public String toString() {
082                    StringBuilder s = new StringBuilder();
083                    for (int i = 0; i < size(); i++) {
084                            s.append(get(i));
085                            if (i < size() - 1) {
086                                    s.append(", ");
087                            }
088                    }
089                    return s.toString();
090            }
091    
092            public void addFirst(A a) {
093                    if (end >= 0) {
094                            start--;
095                            if (start < 0) {
096                                    start = values.length - 1;
097                            }
098                            if (start == end) {
099                                    end--;
100                            }
101                            if (end < 0) {
102                                    end = values.length - 1;
103                            }
104                    } else {
105                            start = 0;
106                            end = 0;
107                    }
108                    values[start] = a;
109            }
110    
111            @SuppressWarnings("unchecked")
112            public A get(int index) {
113                    return (A) values[(start + index) % values.length];
114            }
115    
116            @SuppressWarnings("unchecked")
117            public A set(int index, A a) {
118                    A old = (A) values[(start + index) % values.length];
119                    values[(start + index) % values.length] = a;
120                    return old;
121            }
122    
123            public void clear() {
124                    start = -1;
125                    end = -1;
126            }
127    
128            public void add(int index, A element) {
129                    new Exception("not implemented").printStackTrace();
130            }
131    
132            public boolean addAll(Collection<? extends A> c) {
133                    for (A a : c) {
134                            add(a);
135                    }
136                    return false;
137            }
138    
139            public boolean addAll(int index, Collection<? extends A> c) {
140                    new Exception("not implemented").printStackTrace();
141                    return false;
142            }
143    
144            public boolean contains(Object o) {
145                    for (int i = size(); --i >= 0;) {
146                            if (o.equals(get(i))) {
147                                    return true;
148                            }
149                    }
150                    return false;
151            }
152    
153            public boolean containsAll(Collection<?> c) {
154                    for (Object o : c) {
155                            if (!contains(o)) {
156                                    return false;
157                            }
158                    }
159                    return true;
160            }
161    
162            public int indexOf(Object o) {
163                    for (int i = 0; i < size(); i++) {
164                            if (o.equals(get(i))) {
165                                    return i;
166                            }
167                    }
168                    return -1;
169            }
170    
171            public boolean isEmpty() {
172                    return size() == 0;
173            }
174    
175            public Iterator<A> iterator() {
176                    return new RingBufferIterator();
177            }
178    
179            private class RingBufferIterator implements Iterator<A> {
180    
181                    int pos = 0;
182    
183                    public RingBufferIterator() {
184                    }
185    
186                    public boolean hasNext() {
187                            return pos < size();
188                    }
189    
190                    public A next() {
191                            A a = get(pos);
192                            pos++;
193                            return a;
194                    }
195    
196                    public void remove() {
197                            new Exception("not implemented").printStackTrace();
198                    }
199    
200            }
201    
202            public int lastIndexOf(Object o) {
203                    for (int i = size(); --i >= 0;) {
204                            if (o.equals(get(i))) {
205                                    return i;
206                            }
207                    }
208                    return -1;
209            }
210    
211            public ListIterator<A> listIterator() {
212                    new Exception("not implemented").printStackTrace();
213                    return null;
214            }
215    
216            public ListIterator<A> listIterator(int index) {
217                    new Exception("not implemented").printStackTrace();
218                    return null;
219            }
220    
221            public boolean remove(Object o) {
222                    new Exception("not implemented").printStackTrace();
223                    return false;
224            }
225    
226            public A remove(int index) {
227                    new Exception("not implemented").printStackTrace();
228                    return null;
229            }
230    
231            public boolean removeAll(Collection<?> c) {
232                    new Exception("not implemented").printStackTrace();
233                    return false;
234            }
235    
236            public boolean retainAll(Collection<?> c) {
237                    new Exception("not implemented").printStackTrace();
238                    return false;
239            }
240    
241            public List<A> subList(int fromIndex, int toIndex) {
242                    new Exception("not implemented").printStackTrace();
243                    return null;
244            }
245    
246            public Object[] toArray() {
247                    new Exception("not implemented").printStackTrace();
248                    return null;
249            }
250    
251            public <T> T[] toArray(T[] a) {
252                    new Exception("not implemented").printStackTrace();
253                    return null;
254            }
255    
256    }