001: /*
002: * $Header: /home/cvs/jakarta-commons/primitives/src/java/org/apache/commons/collections/primitives/DoubleCollections.java,v 1.1 2003/10/29 19:39:12 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 DoubleERRUPTION) 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.UnmodifiableDoubleIterator;
061: import org.apache.commons.collections.primitives.decorators.UnmodifiableDoubleList;
062: import org.apache.commons.collections.primitives.decorators.UnmodifiableDoubleListIterator;
063:
064: /**
065: * This class consists exclusively of static methods that operate on or
066: * return DoubleCollections.
067: * <p>
068: * The methods of this class all throw a NullPoDoubleerException if the
069: * provided collection is null.
070: *
071: * @version $Revision: 1.1 $ $Date: 2003/10/29 19:39:12 $
072: *
073: * @author Rodney Waldhoff
074: */
075: public final class DoubleCollections {
076:
077: /**
078: * Returns an unmodifiable DoubleList containing only the specified element.
079: * @param value the single value
080: * @return an unmodifiable DoubleList containing only the specified element.
081: */
082: public static DoubleList singletonDoubleList(double value) {
083: // TODO: a specialized implementation of DoubleList may be more performant
084: DoubleList list = new ArrayDoubleList(1);
085: list.add(value);
086: return UnmodifiableDoubleList.wrap(list);
087: }
088:
089: /**
090: * Returns an unmodifiable DoubleIterator containing only the specified element.
091: * @param value the single value
092: * @return an unmodifiable DoubleIterator containing only the specified element.
093: */
094: public static DoubleIterator singletonDoubleIterator(double value) {
095: return singletonDoubleList(value).iterator();
096: }
097:
098: /**
099: * Returns an unmodifiable DoubleListIterator containing only the specified element.
100: * @param value the single value
101: * @return an unmodifiable DoubleListIterator containing only the specified element.
102: */
103: public static DoubleListIterator singletonDoubleListIterator(
104: double value) {
105: return singletonDoubleList(value).listIterator();
106: }
107:
108: /**
109: * Returns an unmodifiable version of the given non-null DoubleList.
110: * @param list the non-null DoubleList to wrap in an unmodifiable decorator
111: * @return an unmodifiable version of the given non-null DoubleList
112: * @throws NullPoDoubleerException if the given DoubleList is null
113: * @see org.apache.commons.collections.primitives.decorators.UnmodifiableDoubleList#wrap
114: */
115: public static DoubleList unmodifiableDoubleList(DoubleList list)
116: throws NullPointerException {
117: if (null == list) {
118: throw new NullPointerException();
119: }
120: return UnmodifiableDoubleList.wrap(list);
121: }
122:
123: /**
124: * Returns an unmodifiable version of the given non-null DoubleIterator.
125: * @param iter the non-null DoubleIterator to wrap in an unmodifiable decorator
126: * @return an unmodifiable version of the given non-null DoubleIterator
127: * @throws NullPoDoubleerException if the given DoubleIterator is null
128: * @see org.apache.commons.collections.primitives.decorators.UnmodifiableDoubleIterator#wrap
129: */
130: public static DoubleIterator unmodifiableDoubleIterator(
131: DoubleIterator iter) {
132: if (null == iter) {
133: throw new NullPointerException();
134: }
135: return UnmodifiableDoubleIterator.wrap(iter);
136: }
137:
138: /**
139: * Returns an unmodifiable version of the given non-null DoubleListIterator.
140: * @param iter the non-null DoubleListIterator to wrap in an unmodifiable decorator
141: * @return an unmodifiable version of the given non-null DoubleListIterator
142: * @throws NullPoDoubleerException if the given DoubleListIterator is null
143: * @see org.apache.commons.collections.primitives.decorators.UnmodifiableDoubleListIterator#wrap
144: */
145: public static DoubleListIterator unmodifiableDoubleListIterator(
146: DoubleListIterator iter) {
147: if (null == iter) {
148: throw new NullPointerException();
149: }
150: return UnmodifiableDoubleListIterator.wrap(iter);
151: }
152:
153: /**
154: * Returns an unmodifiable, empty DoubleList.
155: * @return an unmodifiable, empty DoubleList.
156: * @see #EMPTY_DOUBLE_LIST
157: */
158: public static DoubleList getEmptyDoubleList() {
159: return EMPTY_DOUBLE_LIST;
160: }
161:
162: /**
163: * Returns an unmodifiable, empty DoubleIterator
164: * @return an unmodifiable, empty DoubleIterator.
165: * @see #EMPTY_DOUBLE_ITERATOR
166: */
167: public static DoubleIterator getEmptyDoubleIterator() {
168: return EMPTY_DOUBLE_ITERATOR;
169: }
170:
171: /**
172: * Returns an unmodifiable, empty DoubleListIterator
173: * @return an unmodifiable, empty DoubleListIterator.
174: * @see #EMPTY_DOUBLE_LIST_ITERATOR
175: */
176: public static DoubleListIterator getEmptyDoubleListIterator() {
177: return EMPTY_DOUBLE_LIST_ITERATOR;
178: }
179:
180: /**
181: * An unmodifiable, empty DoubleList
182: * @see #getEmptyDoubleList
183: */
184: public static final DoubleList EMPTY_DOUBLE_LIST = unmodifiableDoubleList(new ArrayDoubleList(
185: 0));
186:
187: /**
188: * An unmodifiable, empty DoubleIterator
189: * @see #getEmptyDoubleIterator
190: */
191: public static final DoubleIterator EMPTY_DOUBLE_ITERATOR = unmodifiableDoubleIterator(EMPTY_DOUBLE_LIST
192: .iterator());
193:
194: /**
195: * An unmodifiable, empty DoubleListIterator
196: * @see #getEmptyDoubleListIterator
197: */
198: public static final DoubleListIterator EMPTY_DOUBLE_LIST_ITERATOR = unmodifiableDoubleListIterator(EMPTY_DOUBLE_LIST
199: .listIterator());
200: }
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