// Done !!! :D :D :D
public void addSingleIndex(String column, float loadFactor, int bucketSize)
throws IOException, ClassNotFoundException, DBAppException {
if (!ColNameType.containsKey(column)) throw new DBAppException();
singleIndexedColumns.add(column);
LinearHashTable LHT = new LinearHashTable(tableName, column, loadFactor, bucketSize);
for (int i = 1; i <= numberOfPages; i++) {
Page p = (Page) DBApp.readObj("src/classes/Datei/" + tableName + i + ".class");
for (int j = 0; j < p.length(); j++) {
String val = p.getValue(j, column);
if (val != null) LHT.put(p.getValue(j, column), p.getPageNumber() + "#" + j);
}
}
DBApp.writeObj(LHT, "src/classes/Datei/Hashtable#" + tableName + "#" + column + ".class");
}
/**
* Get the value for the given key, or null if not found.
*
* @param p the page
* @param key the key
* @return the value or null
*/
protected Object binarySearch(Page p, Object key) {
int x = p.binarySearch(key);
if (!p.isLeaf()) {
if (x < 0) {
x = -x - 1;
} else {
x++;
}
p = p.getChildPage(x);
return binarySearch(p, key);
}
if (x >= 0) {
return p.getValue(x);
}
return null;
}
/**
* Remove a key-value pair.
*
* @param p the page (may not be null)
* @param writeVersion the write version
* @param key the key
* @return the old value, or null if the key did not exist
*/
protected Object remove(Page p, long writeVersion, Object key) {
int index = p.binarySearch(key);
Object result = null;
if (p.isLeaf()) {
if (index >= 0) {
result = p.getValue(index);
p.remove(index);
if (p.getKeyCount() == 0) {
removePage(p.getPos());
}
}
return result;
}
// node
if (index < 0) {
index = -index - 1;
} else {
index++;
}
Page cOld = p.getChildPage(index);
Page c = copyOnWrite(cOld, writeVersion);
result = remove(c, writeVersion, key);
if (result == null) {
return null;
}
if (c.getTotalCount() == 0) {
// this child was deleted
if (p.getKeyCount() == 0) {
p.setChild(index, c);
p.setCounts(index, c);
removePage(p.getPos());
} else {
p.remove(index);
}
} else {
p.setChild(index, c);
p.setCounts(index, c);
}
return result;
}
