org.apache.jackrabbit.oak.plugins.segment.ListRecord Maven / Gradle / Ivy
/*
* 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.apache.jackrabbit.oak.plugins.segment;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.collect.Lists.newArrayListWithCapacity;
import static java.util.Collections.emptyList;
import static java.util.Collections.singletonList;
import java.util.List;
class ListRecord extends Record {
static final int LEVEL_SIZE = Segment.SEGMENT_REFERENCE_LIMIT;
private final int size;
private final int bucketSize;
ListRecord(Segment segment, RecordId id, int size) {
super(segment, id);
checkArgument(size >= 0);
this.size = size;
int bs = 1;
while (bs * LEVEL_SIZE < size) {
bs *= LEVEL_SIZE;
}
this.bucketSize = bs;
}
public int size() {
return size;
}
public RecordId getEntry(int index) {
checkElementIndex(index, size);
if (size == 1) {
return getRecordId();
} else {
int bucketIndex = index / bucketSize;
int bucketOffset = index % bucketSize;
Segment segment = getSegment();
RecordId id = segment.readRecordId(getOffset(0, bucketIndex));
ListRecord bucket = new ListRecord(
segment, id,
Math.min(bucketSize, size - bucketIndex * bucketSize));
return bucket.getEntry(bucketOffset);
}
}
public List getEntries() {
if (size == 0) {
return emptyList();
} else if (size == 1) {
return singletonList(getRecordId());
} else {
List list = newArrayListWithCapacity(size);
Segment segment = getSegment();
int offset = getOffset();
for (int i = 0; i < size; i += bucketSize) {
RecordId id = segment.readRecordId(offset);
if (bucketSize == 1) {
list.add(id);
} else {
ListRecord bucket = new ListRecord(
segment, id, Math.min(bucketSize, size - i));
list.addAll(bucket.getEntries());
}
offset += Segment.RECORD_ID_BYTES;
}
return list;
}
}
}