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[COLLECTIONS-404] Added the option to provide an Equator to test for equality, by default a DefaultEquator is used that delegates to Object.equals(). 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1477512 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2013-04-30 08:57:06 +00:00
parent 4fa2b6e3ac
commit 44dc835e0a
1 changed files with 31 additions and 9 deletions
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40
src/main/java/org/apache/commons/collections4/sequence/SequencesComparator.java
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@ -18,6 +18,9 @@ package org.apache.commons.collections4.sequence;
import java.util.List;
import org.apache.commons.collections4.functors.DefaultEquator;
import org.apache.commons.collections4.functors.Equator;
/**
* This class allows to compare two objects sequences.
* <p>
@ -61,6 +64,9 @@ public class SequencesComparator<T> {
/** Second sequence. */
private final List<T> sequence2;
/** The equator used for testing object equality. */
private final Equator<? super T> equator;
/** Temporary variables. */
private final int[] vDown;
private final int[] vUp;
@ -68,7 +74,7 @@ public class SequencesComparator<T> {
/**
* Simple constructor.
* <p>
* Creates a new instance of SequencesComparator.
* Creates a new instance of SequencesComparator using a {@link DefaultEquator}.
* <p>
* It is <em>guaranteed</em> that the comparisons will always be done as
* <code>o1.equals(o2)</code> where <code>o1</code> belongs to the first
@ -76,14 +82,30 @@ public class SequencesComparator<T> {
* important if subclassing is used for some elements in the first sequence
* and the <code>equals</code> method is specialized.
*
* @param sequence1
* first sequence to be compared
* @param sequence2
* second sequence to be compared
* @param sequence1 first sequence to be compared
* @param sequence2 second sequence to be compared
*/
public SequencesComparator(final List<T> sequence1, final List<T> sequence2) {
this(sequence1, sequence2, DefaultEquator.defaultEquator());
}
/**
* Simple constructor.
* <p>
* Creates a new instance of SequencesComparator with a custom {@link Equator}.
* <p>
* It is <em>guaranteed</em> that the comparisons will always be done as
* <code>Equator.equate(o1, o2)</code> where <code>o1</code> belongs to the first
* sequence and <code>o2</code> belongs to the second sequence.
*
* @param sequence1 first sequence to be compared
* @param sequence2 second sequence to be compared
* @param equator the equator to use for testing object equality
*/
public SequencesComparator(final List<T> sequence1, final List<T> sequence2, final Equator<? super T> equator) {
this.sequence1 = sequence1;
this.sequence2 = sequence2;
this.equator = equator;
final int size = sequence1.size() + sequence2.size() + 2;
vDown = new int[size];
@ -122,7 +144,7 @@ public class SequencesComparator<T> {
int end = start;
while (end - diag < end2
&& end < end1
&& sequence1.get(end).equals(sequence2.get(end - diag))) {
&& equator.equate(sequence1.get(end), sequence2.get(end - diag))) {
++end;
}
return new Snake(start, end, diag);
@ -174,7 +196,7 @@ public class SequencesComparator<T> {
int x = vDown[i];
int y = x - start1 + start2 - k;
while (x < end1 && y < end2 && sequence1.get(x).equals(sequence2.get(y))) {
while (x < end1 && y < end2 && equator.equate(sequence1.get(x), sequence2.get(y))) {
vDown[i] = ++x;
++y;
}
@ -200,7 +222,7 @@ public class SequencesComparator<T> {
int x = vUp[i] - 1;
int y = x - start1 + start2 - k;
while (x >= start1 && y >= start2
&& sequence1.get(x).equals(sequence2.get(y))) {
&& equator.equate(sequence1.get(x), sequence2.get(y))) {
vUp[i] = x--;
y--;
}
@ -239,7 +261,7 @@ public class SequencesComparator<T> {
int i = start1;
int j = start2;
while (i < end1 || j < end2) {
if (i < end1 && j < end2 && sequence1.get(i).equals(sequence2.get(j))) {
if (i < end1 && j < end2 && equator.equate(sequence1.get(i), sequence2.get(j))) {
script.append(new KeepCommand<T>(sequence1.get(i)));
++i;
++j;