001: /*
002: * $Header: /home/cvs/jakarta-commons/primitives/src/java/org/apache/commons/collections/primitives/IntCollections.java,v 1.2 2003/10/27 23:21:14 rwaldhoff Exp $
003: * ====================================================================
004: * The Apache Software License, Version 1.1
005: *
006: * Copyright (c) 2003 The Apache Software Foundation. All rights
007: * reserved.
008: *
009: * Redistribution and use in source and binary forms, with or without
010: * modification, are permitted provided that the following conditions
011: * are met:
012: *
013: * 1. Redistributions of source code must retain the above copyright
014: * notice, this list of conditions and the following disclaimer.
015: *
016: * 2. Redistributions in binary form must reproduce the above copyright
017: * notice, this list of conditions and the following disclaimer in
018: * the documentation and/or other materials provided with the
019: * distribution.
020: *
021: * 3. The end-user documentation included with the redistribution, if
022: * any, must include the following acknowledgement:
023: * "This product includes software developed by the
024: * Apache Software Foundation (http://www.apache.org/)."
025: * Alternately, this acknowledgement may appear in the software itself,
026: * if and wherever such third-party acknowledgements normally appear.
027: *
028: * 4. The names "The Jakarta Project", "Commons", and "Apache Software
029: * Foundation" must not be used to endorse or promote products derived
030: * from this software without prior written permission. For written
031: * permission, please contact apache@apache.org.
032: *
033: * 5. Products derived from this software may not be called "Apache"
034: * nor may "Apache" appear in their names without prior written
035: * permission of the Apache Software Foundation.
036: *
037: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
038: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
039: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
040: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
041: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
042: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
043: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
044: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
045: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
046: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
047: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
048: * SUCH DAMAGE.
049: * ====================================================================
050: *
051: * This software consists of voluntary contributions made by many
052: * individuals on behalf of the Apache Software Foundation. For more
053: * information on the Apache Software Foundation, please see
054: * <http://www.apache.org/>.
055: *
056: */
057:
058: package org.apache.commons.collections.primitives;
059:
060: import org.apache.commons.collections.primitives.decorators.UnmodifiableIntIterator;
061: import org.apache.commons.collections.primitives.decorators.UnmodifiableIntList;
062: import org.apache.commons.collections.primitives.decorators.UnmodifiableIntListIterator;
063:
064: /**
065: * This class consists exclusively of static methods that operate on or
066: * return IntCollections.
067: * <p>
068: * The methods of this class all throw a NullPointerException if the
069: * provided collection is null.
070: *
071: * @version $Revision: 1.2 $ $Date: 2003/10/27 23:21:14 $
072: *
073: * @author Rodney Waldhoff
074: */
075: public final class IntCollections {
076:
077: /**
078: * Returns an unmodifiable IntList containing only the specified element.
079: * @param value the single value
080: * @return an unmodifiable IntList containing only the specified element.
081: */
082: public static IntList singletonIntList(int value) {
083: // TODO: a specialized implementation of IntList may be more performant
084: IntList list = new ArrayIntList(1);
085: list.add(value);
086: return UnmodifiableIntList.wrap(list);
087: }
088:
089: /**
090: * Returns an unmodifiable IntIterator containing only the specified element.
091: * @param value the single value
092: * @return an unmodifiable IntIterator containing only the specified element.
093: */
094: public static IntIterator singletonIntIterator(int value) {
095: return singletonIntList(value).iterator();
096: }
097:
098: /**
099: * Returns an unmodifiable IntListIterator containing only the specified element.
100: * @param value the single value
101: * @return an unmodifiable IntListIterator containing only the specified element.
102: */
103: public static IntListIterator singletonIntListIterator(int value) {
104: return singletonIntList(value).listIterator();
105: }
106:
107: /**
108: * Returns an unmodifiable version of the given non-null IntList.
109: * @param list the non-null IntList to wrap in an unmodifiable decorator
110: * @return an unmodifiable version of the given non-null IntList
111: * @throws NullPointerException if the given IntList is null
112: * @see org.apache.commons.collections.primitives.decorators.UnmodifiableIntList#wrap
113: */
114: public static IntList unmodifiableIntList(IntList list)
115: throws NullPointerException {
116: if (null == list) {
117: throw new NullPointerException();
118: }
119: return UnmodifiableIntList.wrap(list);
120: }
121:
122: /**
123: * Returns an unmodifiable version of the given non-null IntIterator.
124: * @param iter the non-null IntIterator to wrap in an unmodifiable decorator
125: * @return an unmodifiable version of the given non-null IntIterator
126: * @throws NullPointerException if the given IntIterator is null
127: * @see org.apache.commons.collections.primitives.decorators.UnmodifiableIntIterator#wrap
128: */
129: public static IntIterator unmodifiableIntIterator(IntIterator iter) {
130: if (null == iter) {
131: throw new NullPointerException();
132: }
133: return UnmodifiableIntIterator.wrap(iter);
134: }
135:
136: /**
137: * Returns an unmodifiable version of the given non-null IntListIterator.
138: * @param iter the non-null IntListIterator to wrap in an unmodifiable decorator
139: * @return an unmodifiable version of the given non-null IntListIterator
140: * @throws NullPointerException if the given IntListIterator is null
141: * @see org.apache.commons.collections.primitives.decorators.UnmodifiableIntListIterator#wrap
142: */
143: public static IntListIterator unmodifiableIntListIterator(
144: IntListIterator iter) {
145: if (null == iter) {
146: throw new NullPointerException();
147: }
148: return UnmodifiableIntListIterator.wrap(iter);
149: }
150:
151: /**
152: * Returns an unmodifiable, empty IntList.
153: * @return an unmodifiable, empty IntList.
154: * @see #EMPTY_INT_LIST
155: */
156: public static IntList getEmptyIntList() {
157: return EMPTY_INT_LIST;
158: }
159:
160: /**
161: * Returns an unmodifiable, empty IntIterator
162: * @return an unmodifiable, empty IntIterator.
163: * @see #EMPTY_INT_ITERATOR
164: */
165: public static IntIterator getEmptyIntIterator() {
166: return EMPTY_INT_ITERATOR;
167: }
168:
169: /**
170: * Returns an unmodifiable, empty IntListIterator
171: * @return an unmodifiable, empty IntListIterator.
172: * @see #EMPTY_INT_LIST_ITERATOR
173: */
174: public static IntListIterator getEmptyIntListIterator() {
175: return EMPTY_INT_LIST_ITERATOR;
176: }
177:
178: /**
179: * An unmodifiable, empty IntList
180: * @see #getEmptyIntList
181: */
182: public static final IntList EMPTY_INT_LIST = unmodifiableIntList(new ArrayIntList(
183: 0));
184:
185: /**
186: * An unmodifiable, empty IntIterator
187: * @see #getEmptyIntIterator
188: */
189: public static final IntIterator EMPTY_INT_ITERATOR = unmodifiableIntIterator(EMPTY_INT_LIST
190: .iterator());
191:
192: /**
193: * An unmodifiable, empty IntListIterator
194: * @see #getEmptyIntListIterator
195: */
196: public static final IntListIterator EMPTY_INT_LIST_ITERATOR = unmodifiableIntListIterator(EMPTY_INT_LIST
197: .listIterator());
198: }
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