001 /*
002 * Licensed under the Apache License, Version 2.0 (the "License");
003 * you may not use this file except in compliance with the License.
004 * You may obtain a copy of the License at
005 *
006 * http://www.apache.org/licenses/LICENSE-2.0
007 *
008 * Unless required by applicable law or agreed to in writing, software
009 * distributed under the License is distributed on an "AS IS" BASIS,
010 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
011 * See the License for the specific language governing permissions and
012 * limitations under the License.
013 */
014
015 package org.apache.commons.functor.generator.util;
016
017 import org.apache.commons.functor.UnaryProcedure;
018 import org.apache.commons.functor.generator.BaseGenerator;
019
020 /**
021 * A generator for the range <i>from</i> (inclusive) to <i>to</i> (exclusive).
022 *
023 * @since 1.0
024 * @version $Revision: 1156805 $ $Date: 2011-08-11 22:15:35 +0200 (Thu, 11 Aug 2011) $
025 * @author Jason Horman (jason@jhorman.org)
026 * @author Rodney Waldhoff
027 */
028 public final class LongRange extends BaseGenerator<Long> {
029 // attributes
030 //---------------------------------------------------------------
031
032 private final long from;
033 private final long to;
034 private final long step;
035
036 // constructors
037 //---------------------------------------------------------------
038 /**
039 * Create a new LongRange.
040 * @param from start
041 * @param to end
042 */
043 public LongRange(Number from, Number to) {
044 this(from.longValue(), to.longValue());
045 }
046
047 /**
048 * Create a new LongRange.
049 * @param from start
050 * @param to end
051 * @param step increment
052 */
053 public LongRange(Number from, Number to, Number step) {
054 this(from.longValue(), to.longValue(), step.longValue());
055 }
056
057 /**
058 * Create a new LongRange.
059 * @param from start
060 * @param to end
061 */
062 public LongRange(long from, long to) {
063 this(from, to, defaultStep(from, to));
064 }
065
066 /**
067 * Create a new LongRange.
068 * @param from start
069 * @param to end
070 * @param step increment
071 */
072 public LongRange(long from, long to, long step) {
073 if (from != to && signOf(step) != signOf(to - from)) {
074 throw new IllegalArgumentException("Will never reach " + to + " from " + from + " using step " + step);
075 }
076 this.from = from;
077 this.to = to;
078 this.step = step;
079 }
080
081 // methods
082 //---------------------------------------------------------------
083 /**
084 * {@inheritDoc}
085 */
086 public void run(UnaryProcedure<? super Long> proc) {
087 if (signOf(step) == -1L) {
088 for (long i = from; i > to; i += step) {
089 proc.run(i);
090 }
091 } else {
092 for (long i = from; i < to; i += step) {
093 proc.run(i);
094 }
095 }
096 }
097
098 /**
099 * {@inheritDoc}
100 */
101 public String toString() {
102 return "LongRange<" + from + "," + to + "," + step + ">";
103 }
104
105 /**
106 * {@inheritDoc}
107 */
108 public boolean equals(Object obj) {
109 if (obj == this) {
110 return true;
111 }
112 if (!(obj instanceof LongRange)) {
113 return false;
114 }
115 LongRange that = (LongRange) obj;
116 return this.from == that.from && this.to == that.to && this.step == that.step;
117 }
118
119 /**
120 * {@inheritDoc}
121 */
122 public int hashCode() {
123 int hash = "LongRange".hashCode();
124 hash <<= 2;
125 hash ^= from;
126 hash <<= 2;
127 hash ^= to;
128 hash <<= 2;
129 hash ^= step;
130 return hash;
131 }
132
133 // private methods
134 //---------------------------------------------------------------
135 /**
136 * Get <code>value/|value|</code> (0L when value == 0L).
137 * @param value to test
138 * @return long
139 */
140 private static long signOf(long value) {
141 return value < 0L ? -1L : value > 0L ? 1L : 0L;
142 }
143
144 /**
145 * Calculate default step to get from <code>from</code> to <code>to</code>.
146 * @param from start
147 * @param to end
148 * @return long
149 */
150 private static long defaultStep(long from, long to) {
151 return from > to ? -1L : 1L;
152 }
153
154 }