AfflictionNetworks/samskivert
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Throw a NullPointerException if anyone tries to do anything with null

Browse Source 
elements in the list. I do this because null elements are incompatible
with the implementation details of these utility methods. There were only
two related pieces of code in all our projects that used the behavior
of indexOf(null) and those now use the new indexOfNull() method.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1522 6335cc39-0255-0410-8fd6-9bcaacd3b74c
This commit is contained in:
ray
2004-10-25 18:51:01 +00:00
parent a2d3877796
commit 6513222d5a
1 changed files with 53 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
projects/samskivert/src/java/com/samskivert/util/ListUtil.java
+53 -27
View File
@@ -86,6 +86,9 @@ public class ListUtil
*/
public static Object[] add (Object[] list, int startIdx, Object element)
{
if (element == null) {
throw NPE();
}
// make sure we've got a list to work with
if (list == null) {
list = new Object[DEFAULT_LIST_SIZE];
@@ -127,6 +130,9 @@ public class ListUtil
*/
public static Object[] insert (Object[] list, int index, Object element)
{
if (element == null) {
throw NPE();
}
// make sure we've got a list to work with
if (list == null) {
list = new Object[DEFAULT_LIST_SIZE];
@@ -192,6 +198,9 @@ public class ListUtil
protected static Object[] testAndAdd (
EqualityComparator eqc, Object[] list, Object element)
{
if (element == null) {
throw NPE();
}
// make sure we've got a list to work with
if (list == null) {
list = new Object[DEFAULT_LIST_SIZE];
@@ -229,10 +238,7 @@ public class ListUtil
/**
* Looks for an object that is referentially equal to the supplied
* element (<code>list[idx] == element</code>). Passing a null
* <code>element</code> to this function will cleverly tell you
* whether or not there are any null elements in the array which is
* probably not very useful.
* element (<code>list[idx] == element</code>).
*
* @return true if a matching element was found, false otherwise.
*/
@@ -243,10 +249,7 @@ public class ListUtil
/**
* Looks for an element that is functionally equal to the supplied
* element (<code>list[idx].equals(element)</code>). Passing a null
* <code>element</code> to this function will call
* <code>equals(null)</code> on all objects in the list which may
* cause them to choke, so don't do that unless you mean it.
* element (<code>list[idx].equals(element)</code>).
*
* @return true if a matching element was found, false otherwise.
*/
@@ -259,6 +262,9 @@ public class ListUtil
protected static boolean contains (
EqualityComparator eqc, Object[] list, Object element)
{
if (element == null) {
throw NPE();
}
if (list == null) {
return false;
}
@@ -274,12 +280,26 @@ public class ListUtil
return false;
}
/**
* Returns the lowest index in the array that contains null,
* or -1 if there is no room to add elements without expanding the array.
*/
public static int indexOfNull (Object[] list)
{
if (list != null) {
for (int ii=0, nn = list.length; ii < nn; ii++) {
if (list[ii] == null) {
return ii;
}
}
}
return -1;
}
/**
* Looks for an object that is referentially equal to the supplied
* element (<code>list[idx] == element</code>) and returns its index
* in the array. Passing a null <code>element</code> to this function
* will cleverly tell you whether or not there are any null elements
* in the array which is probably not very useful.
* in the array.
*
* @return the index of the first matching element if one was found,
* -1 otherwise.
@@ -291,10 +311,7 @@ public class ListUtil
/**
* Looks for an element that is functionally equal to the supplied
* element (<code>list[idx].equals(element)</code>). Passing a null
* <code>element</code> to this function will call
* <code>equals(null)</code> on all objects in the list which may
* cause them to choke, so don't do that unless you mean it.
* element (<code>list[idx].equals(element)</code>).
*
* @return the index of the matching element if one was found, -1
* otherwise.
@@ -308,6 +325,9 @@ public class ListUtil
protected static int indexOf (
EqualityComparator eqc, Object[] list, Object element)
{
if (element == null) {
throw NPE();
}
if (list != null) {
int llength = list.length; // no optimizing bastards
for (int i = 0; i < llength; i++) {
@@ -322,10 +342,7 @@ public class ListUtil
/**
* Clears out the first element that is referentially equal to the
* supplied element (<code>list[idx] == element</code>). Passing a
* null <code>element</code> to this function will cleverly tell you
* the index of the first null element in the array which it will have
* kindly overwritten with null just for good measure.
* supplied element (<code>list[idx] == element</code>).
*
* @return the element that was removed or null if it was not found.
*/
@@ -336,10 +353,7 @@ public class ListUtil
/**
* Clears out the first element that is functionally equal to the
* supplied element (<code>list[idx].equals(element)</code>). Passing
* a null <code>element</code> to this function will call
* <code>equals(null)</code> on all objects in the list which may
* cause them to choke, so don't do that unless you mean it.
* supplied element (<code>list[idx].equals(element)</code>).
*
* @return the object that was cleared from the array or null if no
* matching object was found.
@@ -353,6 +367,9 @@ public class ListUtil
protected static Object clear (
EqualityComparator eqc, Object[] list, Object element)
{
if (element == null) {
throw NPE();
}
// nothing to clear from an empty list
if (list == null) {
return null;
@@ -387,10 +404,7 @@ public class ListUtil
* Removes the first element that is functionally equal to the
* supplied element (<code>list[idx].equals(element)</code>). The
* elements after the removed element will be slid down the array one
* spot to fill the place of the removed element. Passing a null
* <code>element</code> to this function will call
* <code>equals(null)</code> on all objects in the list which may
* cause them to choke, so don't do that unless you mean it.
* spot to fill the place of the removed element.
*
* @return the object that was removed from the array or null if no
* matching object was found.
@@ -404,6 +418,9 @@ public class ListUtil
protected static Object remove (
EqualityComparator eqc, Object[] list, Object element)
{
if (element == null) {
throw NPE();
}
// nothing to remove from an empty list
if (list == null) {
return null;
@@ -476,6 +493,15 @@ public class ListUtil
return newlist;
}
/**
* Throw a NullPointerException with the bad news.
*/
protected static NullPointerException NPE ()
{
return new NullPointerException(
"ListUtil does not support null elements.");
}
/**
* Run some tests.
*/