jstrachan 01/08/29 09:10:29
Modified: collections/src/java/org/apache/commons/collections
CollectionUtils.java
Log:
Added Bay's helper methods to CollectionUtils
Revision Changes Path
1.5 +114 -4
jakarta-commons/collections/src/java/org/apache/commons/collections/CollectionUtils.java
Index: CollectionUtils.java
===================================================================
RCS file:
/home/cvs/jakarta-commons/collections/src/java/org/apache/commons/collections/CollectionUtils.java,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- CollectionUtils.java 2001/05/22 15:53:06 1.4
+++ CollectionUtils.java 2001/08/29 16:10:29 1.5
@@ -1,7 +1,7 @@
/*
- * $Header:
/home/cvs/jakarta-commons/collections/src/java/org/apache/commons/collections/CollectionUtils.java,v
1.4 2001/05/22 15:53:06 jstrachan Exp $
- * $Revision: 1.4 $
- * $Date: 2001/05/22 15:53:06 $
+ * $Header:
/home/cvs/jakarta-commons/collections/src/java/org/apache/commons/collections/CollectionUtils.java,v
1.5 2001/08/29 16:10:29 jstrachan Exp $
+ * $Revision: 1.5 $
+ * $Date: 2001/08/29 16:10:29 $
*
* ====================================================================
*
@@ -67,6 +67,7 @@
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
+import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
@@ -76,7 +77,7 @@
*
* @author Rodney Waldhoff
*
- * @version $Id: CollectionUtils.java,v 1.4 2001/05/22 15:53:06 jstrachan Exp $
+ * @version $Id: CollectionUtils.java,v 1.5 2001/08/29 16:10:29 jstrachan Exp $
*/
public class CollectionUtils {
/**
@@ -407,6 +408,115 @@
}
}
+ /**
+ * Given an Object, and an index, it will get the nth value in the
+ * object.
+ */
+ public static Object index(Object obj, int idx) {
+ return index(obj, new Integer(idx));
+ }
+
+ /**
+ * Given an Object, and an index, it will get the nth value in the
+ * object.
+ */
+ public static Object index(Object obj, Object index) {
+ if(obj instanceof Map) {
+ Map map = (Map)obj;
+ if(map.containsKey(index)) {
+ return map.get(index);
+ }
+ }
+ int idx = -1;
+ if(index instanceof Integer) {
+ idx = ((Integer)index).intValue();
+ }
+ if(idx < 0) {
+ return obj;
+ }
+ else if(obj instanceof Map) {
+ Map map = (Map)obj;
+ Iterator iterator = map.keySet().iterator();
+ while(iterator.hasNext()) {
+ idx--;
+ if(idx == -1) {
+ return iterator.next();
+ } else {
+ iterator.next();
+ }
+ }
+ }
+ else if(obj instanceof List) {
+ return ((List)obj).get(idx);
+ }
+ else if(obj instanceof Object[]) {
+ return ((Object[])obj)[idx];
+ }
+ else if(obj instanceof Enumeration) {
+ Enumeration enum = (Enumeration)obj;
+ while(enum.hasMoreElements()) {
+ idx--;
+ if(idx == -1) {
+ return enum.nextElement();
+ } else {
+ enum.nextElement();
+ }
+ }
+ }
+ else if(obj instanceof Iterator) {
+ Iterator iterator = (Iterator)obj;
+ while(iterator.hasNext()) {
+ idx--;
+ if(idx == -1) {
+ return iterator.next();
+ } else {
+ iterator.next();
+ }
+ }
+ }
+ return obj;
+ }
+
+ /** Returns an Iterator for the given object. Currently this method can handle
+ * Iterator, Enumeration, Collection, Map, Object[] or array */
+ public static Iterator getIterator(Object obj) {
+ if(obj instanceof Iterator) {
+ return (Iterator)obj;
+ }
+ else if(obj instanceof Collection) {
+ return ((Collection)obj).iterator();
+ }
+ else if(obj instanceof Object[]) {
+ return new ArrayIterator( obj );
+ }
+ else if(obj instanceof Enumeration) {
+ return new EnumerationIterator( (Enumeration)obj );
+ }
+ else if(obj instanceof Map) {
+ return ((Map)obj).values().iterator();
+ }
+ else if(obj != null && obj.getClass().isArray()) {
+ return new ArrayIterator( obj );
+ }
+ else{
+ return null;
+ }
+ }
+
+ /** Reverses the order of the given array */
+ public static void reverseArray(Object[] array) {
+ int i = 0;
+ int j = array.length - 1;
+ Object tmp;
+
+ while(j>i) {
+ tmp = array[j];
+ array[j] = array[i];
+ array[i] = tmp;
+ j--;
+ i++;
+ }
+ }
private static final int getFreq(final Object obj, final Map freqMap) {
try {
return ((Integer)(freqMap.get(obj))).intValue();
