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This is the ehcache core module. Pair it with other modules for added functionality.
/**
* Copyright 2003-2010 Terracotta, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.sf.ehcache.store.disk.ods;
/**
* A region set based on an augmented AA-Tree.
*
* @author Chris Dennis
*/
class RegionSet extends AATreeSet {
private final long size;
/**
* Construct the tree.
*/
protected RegionSet(long size) {
super();
add(new Region(0, size - 1));
this.size = size;
}
@Override
public Region removeAndReturn(Object o) {
Region r = super.removeAndReturn(o);
if (r != null) {
return new Region(r);
} else {
return null;
}
}
@Override
public Region find(Object o) {
Region r = super.find(o);
if (r != null) {
return new Region(r);
} else {
return null;
}
}
/**
* Find a region of the the given size.
*/
public Region find(long size) {
Node currentNode = getRoot();
Region currentRegion = currentNode.getPayload();
if (currentRegion == null || size > currentRegion.contiguous()) {
throw new IllegalArgumentException("Need to grow the region set");
} else {
while (true) {
if (currentRegion.size() >= size) {
return new Region(currentRegion.start(), currentRegion.start() + size - 1);
} else {
Region left = currentNode.getLeft().getPayload();
Region right = currentNode.getRight().getPayload();
if (left != null && left.contiguous() >= size) {
currentNode = currentNode.getLeft();
currentRegion = currentNode.getPayload();
} else if (right != null && right.contiguous() >= size) {
currentNode = currentNode.getRight();
currentRegion = currentNode.getPayload();
} else {
throw new IllegalArgumentException("Couldn't find a " + size + " sized free area in " + currentRegion);
}
}
}
}
}
}