/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.fusesource.hawtdb.internal.page;
import java.util.Iterator;
import org.fusesource.hawtdb.api.Allocator;
import org.fusesource.hawtdb.api.OutOfSpaceException;
import org.fusesource.hawtdb.internal.util.Ranges;
import org.fusesource.hawtdb.internal.util.Ranges.Range;
import static org.fusesource.hawtdb.internal.page.Logging.*;
/**
* This class is used to provides allocation management of pages.
*
* @author <a href="http://hiramchirino.com">Hiram Chirino</a>
*/
public class SimpleAllocator implements Allocator {
private final Ranges freeRanges = new Ranges();
private volatile int limit;
public SimpleAllocator(int limit) {
this.limit = limit;
freeRanges.add(0, limit);
}
private void op_trace(String op, int page, int count) {
if( traced(page) ) {
trace("%s: %d : %d", op, page, count);
}
}
/**
* @see Allocator#alloc(int)
*/
synchronized public int alloc(int size) throws OutOfSpaceException {
for (Iterator<Range> i = freeRanges.iterator(); i.hasNext();) {
Range r = (Range) i.next();
if( r.size() >= size ) {
int rc = r.start;
op_trace("ALLOC", rc, size);
freeRanges.remove(rc, size);
return rc;
}
}
throw new OutOfSpaceException();
}
/**
* @see Allocator#free(int, int)
*/
synchronized public void free(int pageId, int count) {
freeRanges.add(pageId, count);
op_trace("FREE", pageId, count);
}
/**
* @see Allocator#unfree(int, int)
*/
synchronized public void unfree(int pageId, int count) {
freeRanges.remove(pageId, count);
}
synchronized public void clear() throws UnsupportedOperationException {
freeRanges.clear();
freeRanges.add(0, limit);
}
synchronized public void setFreeRanges(Ranges freePages) throws UnsupportedOperationException {
freeRanges.copy(freePages);
}
public int getLimit() {
return limit;
}
public boolean isAllocated(int page) {
return !freeRanges.contains(page);
}
public Ranges getFreeRanges() {
return freeRanges;
}
@Override
public String toString() {
return "{ free pages: "+freeRanges.toString()+" }";
}
}