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Posted to commits@commons.apache.org by er...@apache.org on 2015/10/31 15:40:10 UTC
[math] MATH-1286
Repository: commons-math
Updated Branches:
refs/heads/master 8ed2209b1 -> fa1aa44c7
MATH-1286
New "Range" inner class that holds a field with the number of elements of the range.
An instance of this class replaces the anonymous class returned by the "range" method.
Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/fa1aa44c
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/fa1aa44c
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/fa1aa44c
Branch: refs/heads/master
Commit: fa1aa44c7623fb2142e588c59eaf56db7bc237eb
Parents: 8ed2209
Author: Gilles <er...@apache.org>
Authored: Sat Oct 31 15:36:35 2015 +0100
Committer: Gilles <er...@apache.org>
Committed: Sat Oct 31 15:36:35 2015 +0100
----------------------------------------------------------------------
src/changes/changes.xml | 3 +
.../commons/math4/util/IntegerSequence.java | 74 ++++++++++++++++----
.../commons/math4/util/IntegerSequenceTest.java | 47 +++++++++++--
3 files changed, 102 insertions(+), 22 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/commons-math/blob/fa1aa44c/src/changes/changes.xml
----------------------------------------------------------------------
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 55a8fcb..d31605c 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -54,6 +54,9 @@ If the output is not quite correct, check for invisible trailing spaces!
</release>
<release version="4.0" date="XXXX-XX-XX" description="">
+ <action dev="erans" type="add" issue="MATH-1286">
+ New "Range" inner class of "o.a.c.m.util.IntegerSequence".
+ </action>
<action dev="oertl" type="fix" issue="MATH-1285" due-to="Pim van der Hoorn "> <!-- backported to 3.6 -->
Updated reference in ZipfDistribution's javadoc.
</action>
http://git-wip-us.apache.org/repos/asf/commons-math/blob/fa1aa44c/src/main/java/org/apache/commons/math4/util/IntegerSequence.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math4/util/IntegerSequence.java b/src/main/java/org/apache/commons/math4/util/IntegerSequence.java
index 1a16b0c..233ce3a 100644
--- a/src/main/java/org/apache/commons/math4/util/IntegerSequence.java
+++ b/src/main/java/org/apache/commons/math4/util/IntegerSequence.java
@@ -42,8 +42,8 @@ public class IntegerSequence {
* @param end Last value of the range.
* @return a range.
*/
- public static Iterable<Integer> range(int start,
- int end) {
+ public static Range range(int start,
+ int end) {
return range(start, end, 1);
}
@@ -58,19 +58,63 @@ public class IntegerSequence {
* @param step Increment.
* @return a range.
*/
- public static Iterable<Integer> range(final int start,
- final int max,
- final int step) {
- return new Iterable<Integer>() {
- /** {@inheritDoc} */
- @Override
- public Iterator<Integer> iterator() {
- return Incrementor.create()
- .withStart(start)
- .withMaximalCount(max + (step > 0 ? 1 : -1))
- .withIncrement(step);
- }
- };
+ public static Range range(final int start,
+ final int max,
+ final int step) {
+ return new Range(start, max, step);
+ }
+
+ /**
+ * Generates a sequence of integers.
+ */
+ public static class Range implements Iterable<Integer> {
+ /** Number of integers contained in this range. */
+ private final int size;
+ /** First value. */
+ private final int start;
+ /** Final value. */
+ private final int max;
+ /** Increment. */
+ private final int step;
+
+ /**
+ * Creates a sequence \( a_i, i < 0 <= n \)
+ * where \( a_i = start + i * step \)
+ * and \( n \) is such that \( a_n <= max \) and \( a_{n+1} > max \).
+ *
+ * @param start First value of the range.
+ * @param max Last value of the range that satisfies the above
+ * construction rule.
+ * @param step Increment.
+ */
+ public Range(int start,
+ int max,
+ int step) {
+ this.start = start;
+ this.max = max;
+ this.step = step;
+
+ final int s = (max - start) / step + 1;
+ this.size = s < 0 ? 0 : s;
+ }
+
+ /**
+ * Gets the number of elements contained in the range.
+ *
+ * @return the size of the range.
+ */
+ public int size() {
+ return size;
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public Iterator<Integer> iterator() {
+ return Incrementor.create()
+ .withStart(start)
+ .withMaximalCount(max + (step > 0 ? 1 : -1))
+ .withIncrement(step);
+ }
}
/**
http://git-wip-us.apache.org/repos/asf/commons-math/blob/fa1aa44c/src/test/java/org/apache/commons/math4/util/IntegerSequenceTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math4/util/IntegerSequenceTest.java b/src/test/java/org/apache/commons/math4/util/IntegerSequenceTest.java
index d1a6764..25eec4f 100644
--- a/src/test/java/org/apache/commons/math4/util/IntegerSequenceTest.java
+++ b/src/test/java/org/apache/commons/math4/util/IntegerSequenceTest.java
@@ -27,17 +27,40 @@ import org.junit.Test;
*/
public class IntegerSequenceTest {
@Test
+ public void testRangeMultipleIterations() {
+ // Check that we can iterate several times using the same instance.
+ final int start = 1;
+ final int max = 7;
+ final int step = 2;
+
+ final List<Integer> seq = new ArrayList<Integer>();
+ final IntegerSequence.Range r = IntegerSequence.range(start, max, step);
+
+ final int numTimes = 3;
+ for (int n = 0; n < numTimes; n++) {
+ seq.clear();
+ for (Integer i : r) {
+ seq.add(i);
+ }
+ Assert.assertEquals(4, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
+ }
+ }
+
+ @Test
public void testIncreasingRange() {
final int start = 1;
final int max = 7;
final int step = 2;
final List<Integer> seq = new ArrayList<Integer>();
- for (Integer i : IntegerSequence.range(start, max, step)) {
+ final IntegerSequence.Range r = IntegerSequence.range(start, max, step);
+ for (Integer i : r) {
seq.add(i);
}
Assert.assertEquals(4, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
for (int i = 0; i < seq.size(); i++) {
Assert.assertEquals(start + i * step, seq.get(i).intValue());
}
@@ -50,11 +73,13 @@ public class IntegerSequenceTest {
final int step = 2;
final List<Integer> seq = new ArrayList<Integer>();
- for (Integer i : IntegerSequence.range(start, max, step)) {
+ final IntegerSequence.Range r = IntegerSequence.range(start, max, step);
+ for (Integer i : r) {
seq.add(i);
}
Assert.assertEquals(5, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
for (int i = 0; i < seq.size(); i++) {
Assert.assertEquals(start + i * step, seq.get(i).intValue());
}
@@ -67,11 +92,13 @@ public class IntegerSequenceTest {
final int step = -3;
final List<Integer> seq = new ArrayList<Integer>();
- for (Integer i : IntegerSequence.range(start, max, step)) {
+ final IntegerSequence.Range r = IntegerSequence.range(start, max, step);
+ for (Integer i : r) {
seq.add(i);
}
Assert.assertEquals(7, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
for (int i = 0; i < seq.size(); i++) {
Assert.assertEquals(start + i * step, seq.get(i).intValue());
}
@@ -84,11 +111,13 @@ public class IntegerSequenceTest {
final int step = -1;
final List<Integer> seq = new ArrayList<Integer>();
- for (Integer i : IntegerSequence.range(start, max, step)) {
+ final IntegerSequence.Range r = IntegerSequence.range(start, max, step);
+ for (Integer i : r) {
seq.add(i);
}
Assert.assertEquals(1, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
Assert.assertEquals(start, seq.get(0).intValue());
}
@@ -110,14 +139,16 @@ public class IntegerSequenceTest {
@Test
public void testEmptyRange() {
final int start = 2;
- final int end = 1;
+ final int end = 0;
final List<Integer> seq = new ArrayList<Integer>();
- for (Integer i : IntegerSequence.range(start, end)) {
+ final IntegerSequence.Range r = IntegerSequence.range(start, end);
+ for (Integer i : r) {
seq.add(i);
}
Assert.assertEquals(0, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
}
@Test
@@ -127,11 +158,13 @@ public class IntegerSequenceTest {
final int step = -1;
final List<Integer> seq = new ArrayList<Integer>();
- for (Integer i : IntegerSequence.range(start, max, step)) {
+ final IntegerSequence.Range r = IntegerSequence.range(start, max, step);
+ for (Integer i : r) {
seq.add(i);
}
Assert.assertEquals(0, seq.size());
+ Assert.assertEquals(seq.size(), r.size());
}
@Test(expected=MaxCountExceededException.class)