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Brought testAndAdd() into line with all the other methods which have a

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referential equality version foo() and an object equality version
fooEqual().

Modified the code so that the same version of each function can be used to
implement the referential and object equality versions with the help of an
equality comparator class.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@968 6335cc39-0255-0410-8fd6-9bcaacd3b74c
This commit is contained in:
mdb
2002-12-12 00:29:39 +00:00
parent b3e5c848f8
commit 2ddd5a3b4a
1 changed files with 87 additions and 54 deletions
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projects/samskivert/src/java/com/samskivert/util/ListUtil.java
+87 -54
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@@ -1,5 +1,5 @@
//
// $Id: ListUtil.java,v 1.10 2002/10/23 23:31:32 mdb Exp $
// $Id: ListUtil.java,v 1.11 2002/12/12 00:29:39 mdb Exp $
package com.samskivert.util;
@@ -154,6 +154,23 @@ public class ListUtil
return list;
}
/**
* Searches through the list checking to see if the element supplied
* is already in the list (using reference equality to check for
* existence) and adds it if it is not.
*
* @param list the list to which to add the element. Can be null.
* @param element the element to test and add.
*
* @return a reference to the list with element added (might not be
* the list you passed in due to expansion, or allocation) or null if
* the element was already in the original array.
*/
public static Object[] testAndAdd (Object[] list, Object element)
{
return testAndAdd(REFERENCE_COMP, list, element);
}
/**
* Searches through the list checking to see if the element supplied
* is already in the list (using <code>equals()</code> to check for
@@ -166,7 +183,14 @@ public class ListUtil
* the list you passed in due to expansion, or allocation) or null if
* the element was already in the original array.
*/
public static Object[] testAndAdd (Object[] list, Object element)
public static Object[] testAndAddEqual (Object[] list, Object element)
{
return testAndAdd(EQUALS_COMP, list, element);
}
/** Helper function for {@link #testAndAdd}, etc. */
protected static Object[] testAndAdd (
EqualityComparator eqc, Object[] list, Object element)
{
// make sure we've got a list to work with
if (list == null) {
@@ -186,7 +210,7 @@ public class ListUtil
index = i;
}
} else if (elem.equals(element)) {
} else if (eqc.equals(elem, element)) {
// oops, it's already in the list
return null;
}
@@ -214,17 +238,7 @@ public class ListUtil
*/
public static boolean contains (Object[] list, Object element)
{
if (list == null) {
return false;
}
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
if (list[i] == element) {
return true;
}
}
return false;
return contains(REFERENCE_COMP, list, element);
}
/**
@@ -237,6 +251,13 @@ public class ListUtil
* @return true if a matching element was found, false otherwise.
*/
public static boolean containsEqual (Object[] list, Object element)
{
return contains(EQUALS_COMP, list, element);
}
/** Helper function for {@link #contains}, etc. */
protected static boolean contains (
EqualityComparator eqc, Object[] list, Object element)
{
if (list == null) {
return false;
@@ -245,10 +266,11 @@ public class ListUtil
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
Object elem = list[i];
if (elem != null && elem.equals(element)) {
if (eqc.equals(elem, element)) {
return true;
}
}
return false;
}
@@ -264,13 +286,7 @@ public class ListUtil
*/
public static int indexOf (Object[] list, Object element)
{
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
if (list[i] == element) {
return i;
}
}
return -1;
return indexOf(REFERENCE_COMP, list, element);
}
/**
@@ -284,11 +300,18 @@ public class ListUtil
* otherwise.
*/
public static int indexOfEqual (Object[] list, Object element)
{
return indexOf(EQUALS_COMP, list, element);
}
/** Helper function for {@link #indexOf}, etc. */
protected static int indexOf (
EqualityComparator eqc, Object[] list, Object element)
{
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
Object elem = list[i];
if (elem != null && elem.equals(element)) {
if (eqc.equals(elem, element)) {
return i;
}
}
@@ -306,20 +329,7 @@ public class ListUtil
*/
public static Object clear (Object[] list, Object element)
{
// nothing to clear from an empty list
if (list == null) {
return null;
}
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
Object elem = list[i];
if (elem == element) {
list[i] = null;
return elem;
}
}
return null;
return clear(REFERENCE_COMP, list, element);
}
/**
@@ -333,6 +343,13 @@ public class ListUtil
* matching object was found.
*/
public static Object clearEqual (Object[] list, Object element)
{
return clear(EQUALS_COMP, list, element);
}
/** Helper function for {@link #clear}, etc. */
protected static Object clear (
EqualityComparator eqc, Object[] list, Object element)
{
// nothing to clear from an empty list
if (list == null) {
@@ -342,7 +359,7 @@ public class ListUtil
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
Object elem = list[i];
if (elem != null && elem.equals(element)) {
if (eqc.equals(elem, element)) {
list[i] = null;
return elem;
}
@@ -361,21 +378,7 @@ public class ListUtil
*/
public static Object remove (Object[] list, Object element)
{
// nothing to remove from an empty list
if (list == null) {
return null;
}
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
Object elem = list[i];
if (elem == element) {
System.arraycopy(list, i+1, list, i, llength-(i+1));
list[llength-1] = null;
return elem;
}
}
return null;
return remove(REFERENCE_COMP, list, element);
}
/**
@@ -391,6 +394,13 @@ public class ListUtil
* matching object was found.
*/
public static Object removeEqual (Object[] list, Object element)
{
return remove(EQUALS_COMP, list, element);
}
/** Helper function for {@link #remove}, etc. */
protected static Object remove (
EqualityComparator eqc, Object[] list, Object element)
{
// nothing to remove from an empty list
if (list == null) {
@@ -400,7 +410,7 @@ public class ListUtil
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
Object elem = list[i];
if (elem != null && elem.equals(element)) {
if (eqc.equals(elem, element)) {
System.arraycopy(list, i+1, list, i, llength-(i+1));
list[llength-1] = null;
return elem;
@@ -532,6 +542,29 @@ public class ListUtil
}
}
/** Used to allow the same code to optionally use reference equality
* and {@link Object#equals}.equality. */
protected static interface EqualityComparator
{
public boolean equals (Object o1, Object o2);
}
protected static final EqualityComparator REFERENCE_COMP =
new EqualityComparator() {
public boolean equals (Object o1, Object o2)
{
return o1 == o2;
}
};
protected static final EqualityComparator EQUALS_COMP =
new EqualityComparator() {
public boolean equals (Object o1, Object o2)
{
return (o1 == null) ? (o1 == o2) : o1.equals(o2);
}
};
/**
* The size of a list to create if we have to create one entirely
* from scratch rather than just expand it.