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Improve capacity handling and checks for large maps 

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@131773 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne 2004-06-04 23:27:30 +00:00
parent f959880118
commit b72b6f471c
1 changed files with 30 additions and 21 deletions
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51
src/java/org/apache/commons/collections/map/AbstractHashedMap.java
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@ -47,7 +47,7 @@ import org.apache.commons.collections.iterators.EmptyMapIterator;
* need for unusual subclasses is here.
*
* @since Commons Collections 3.0
* @version $Revision: 1.18 $ $Date: 2004/05/26 21:56:05 $
* @version $Revision: 1.19 $ $Date: 2004/06/04 23:27:30 $
*
* @author java util HashMap
* @author Stephen Colebourne
@ -292,7 +292,8 @@ public class AbstractHashedMap implements IterableMap {
if (mapSize == 0) {
return;
}
ensureCapacity(calculateNewCapacity(size + mapSize));
int newSize = (int) ((size + mapSize) / loadFactor + 1);
ensureCapacity(calculateNewCapacity(newSize));
for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
Map.Entry entry = (Map.Entry) it.next();
put(entry.getKey(), entry.getValue());
@ -578,39 +579,47 @@ public class AbstractHashedMap implements IterableMap {
*/
protected void checkCapacity() {
if (size >= threshold) {
ensureCapacity(data.length * 2);
int newCapacity = data.length * 2;
if (newCapacity <= MAXIMUM_CAPACITY) {
ensureCapacity(newCapacity);
}
}
}
/**
* Changes the size of the data structure to the capacity proposed.
*
* @param newCapacity the new capacity of the array
* @param newCapacity the new capacity of the array (a power of two, less or equal to max)
*/
protected void ensureCapacity(int newCapacity) {
int oldCapacity = data.length;
if (newCapacity <= oldCapacity) {
return;
}
HashEntry oldEntries[] = data;
HashEntry newEntries[] = new HashEntry[newCapacity];
if (size == 0) {
threshold = calculateThreshold(newCapacity, loadFactor);
data = new HashEntry[newCapacity];
} else {
HashEntry oldEntries[] = data;
HashEntry newEntries[] = new HashEntry[newCapacity];
modCount++;
for (int i = oldCapacity - 1; i >= 0; i--) {
HashEntry entry = oldEntries[i];
if (entry != null) {
oldEntries[i] = null; // gc
do {
HashEntry next = entry.next;
int index = hashIndex(entry.hashCode, newCapacity);
entry.next = newEntries[index];
newEntries[index] = entry;
entry = next;
} while (entry != null);
modCount++;
for (int i = oldCapacity - 1; i >= 0; i--) {
HashEntry entry = oldEntries[i];
if (entry != null) {
oldEntries[i] = null; // gc
do {
HashEntry next = entry.next;
int index = hashIndex(entry.hashCode, newCapacity);
entry.next = newEntries[index];
newEntries[index] = entry;
entry = next;
} while (entry != null);
}
}
threshold = calculateThreshold(newCapacity, loadFactor);
data = newEntries;
}
threshold = calculateThreshold(newCapacity, loadFactor);
data = newEntries;
}
/**
@ -628,7 +637,7 @@ public class AbstractHashedMap implements IterableMap {
while (newCapacity < proposedCapacity) {
newCapacity <<= 1; // multiply by two
}
if (proposedCapacity > MAXIMUM_CAPACITY) {
if (newCapacity > MAXIMUM_CAPACITY) {
newCapacity = MAXIMUM_CAPACITY;
}
}