/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.bytecode.enhance.internal.tracker;
/**
* small low memory class to keep track of changed fields
*
* similar to BasicTracker but where the array is kept ordered to reduce the cost of verifying duplicates
*
* @author <a href="mailto:lbarreiro@redhat.com">Luis Barreiro</a>
*/
public final class SortedFieldTracker implements DirtyTracker {
private String[] names;
private boolean suspended;
public SortedFieldTracker() {
names = new String[0];
}
@Override
public void add(String name) {
if ( suspended ) {
return;
}
// we do a binary search: even if we don't find the name at least we get the position to insert into the array
int insert = 0;
for ( int low = 0, high = names.length - 1; low <= high; ) {
final int middle = low + ( ( high - low ) / 2 );
final int compare = names[middle].compareTo( name );
if ( compare > 0 ) {
// bottom half: higher bound in (middle - 1) and insert position in middle
high = middle - 1;
insert = middle;
}
else if( compare < 0 ) {
// top half: lower bound in (middle + 1) and insert position after middle
insert = low = middle + 1;
}
else {
return;
}
}
final String[] newNames = new String[names.length + 1];
System.arraycopy( names, 0, newNames, 0, insert );
System.arraycopy( names, insert, newNames, insert + 1, names.length - insert );
newNames[insert] = name;
names = newNames;
}
@Override
public boolean contains(String name) {
for ( int low = 0, high = names.length - 1; low <= high; ) {
final int middle = low + ( ( high - low ) / 2 );
final int compare = names[middle].compareTo( name );
if ( compare > 0 ) {
// bottom half: higher bound in (middle - 1) and insert position in middle
high = middle - 1;
}
else if( compare < 0 ) {
// top half: lower bound in (middle + 1) and insert position after middle
low = middle + 1;
}
else {
return true;
}
}
return false;
}
@Override
public void clear() {
if ( !isEmpty() ) {
names = new String[0];
}
}
@Override
public boolean isEmpty() {
return names.length == 0;
}
@Override
public String[] get() {
return names;
}
@Override
public void suspend(boolean suspend) {
this.suspended = suspend;
}
}