/*
* 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.phoenix.compile;
import java.util.Collections;
import java.util.List;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.filter.SkipScanFilter;
import org.apache.phoenix.query.KeyRange;
import org.apache.phoenix.schema.RowKeySchema;
import org.apache.phoenix.util.ScanUtil;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
public class ScanRanges {
private static final List<List<KeyRange>> EVERYTHING_RANGES = Collections.<List<KeyRange>>emptyList();
private static final List<List<KeyRange>> NOTHING_RANGES = Collections.<List<KeyRange>>singletonList(Collections.<KeyRange>singletonList(KeyRange.EMPTY_RANGE));
public static final ScanRanges EVERYTHING = new ScanRanges(EVERYTHING_RANGES,null,false);
public static final ScanRanges NOTHING = new ScanRanges(NOTHING_RANGES,null,false);
public static ScanRanges create(List<List<KeyRange>> ranges, RowKeySchema schema) {
return create(ranges, schema, false);
}
public static ScanRanges create(List<List<KeyRange>> ranges, RowKeySchema schema, boolean forceRangeScan) {
if (ranges.isEmpty()) {
return EVERYTHING;
} else if (ranges.size() == 1 && ranges.get(0).size() == 1 && ranges.get(0).get(0) == KeyRange.EMPTY_RANGE) {
return NOTHING;
}
return new ScanRanges(ranges, schema, forceRangeScan);
}
private SkipScanFilter filter;
private final List<List<KeyRange>> ranges;
private final RowKeySchema schema;
private final boolean forceRangeScan;
private ScanRanges (List<List<KeyRange>> ranges, RowKeySchema schema, boolean forceRangeScan) {
List<List<KeyRange>> sortedRanges = Lists.newArrayListWithExpectedSize(ranges.size());
for (int i = 0; i < ranges.size(); i++) {
List<KeyRange> sorted = Lists.newArrayList(ranges.get(i));
Collections.sort(sorted, KeyRange.COMPARATOR);
sortedRanges.add(ImmutableList.copyOf(sorted));
}
this.ranges = ImmutableList.copyOf(sortedRanges);
this.schema = schema;
if (schema != null && !ranges.isEmpty()) {
this.filter = new SkipScanFilter(this.ranges, schema);
}
this.forceRangeScan = forceRangeScan;
}
public SkipScanFilter getSkipScanFilter() {
return filter;
}
public List<List<KeyRange>> getRanges() {
return ranges;
}
public RowKeySchema getSchema() {
return schema;
}
public boolean isEverything() {
return this == EVERYTHING;
}
public boolean isDegenerate() {
return this == NOTHING;
}
public boolean isPointLookup() {
if (schema == null || forceRangeScan || ranges.size() < schema.getMaxFields()) {
return false;
}
for (List<KeyRange> orRanges : ranges) {
for (KeyRange keyRange : orRanges) {
if (!keyRange.isSingleKey()) {
return false;
}
}
}
return true;
}
/**
* Use SkipScanFilter under two circumstances:
* 1) If we have multiple ranges for a given key slot (use of IN)
* 2) If we have a range (i.e. not a single/point key) that is
* not the last key slot
*/
public boolean useSkipScanFilter() {
if (forceRangeScan) {
return false;
}
boolean hasRangeKey = false, useSkipScan = false;
for (List<KeyRange> orRanges : ranges) {
useSkipScan |= orRanges.size() > 1 | hasRangeKey;
if (useSkipScan) {
return true;
}
for (KeyRange range : orRanges) {
hasRangeKey |= !range.isSingleKey();
}
}
return false;
}
/**
* @return true if this represents the full key to a single row
*/
public boolean isSingleRowScan() {
if (schema == null || ranges.size() < schema.getMaxFields()) {
return false;
}
boolean isSingleKey = true;
for (List<KeyRange> orRanges : ranges) {
if (orRanges.size() > 1) {
return false;
}
isSingleKey &= orRanges.get(0).isSingleKey();
}
return isSingleKey;
}
public void setScanStartStopRow(Scan scan) {
if (isEverything()) {
return;
}
if (isDegenerate()) {
scan.setStartRow(KeyRange.EMPTY_RANGE.getLowerRange());
scan.setStopRow(KeyRange.EMPTY_RANGE.getUpperRange());
return;
}
byte[] expectedKey;
expectedKey = ScanUtil.getMinKey(schema, ranges);
if (expectedKey != null) {
scan.setStartRow(expectedKey);
}
expectedKey = ScanUtil.getMaxKey(schema, ranges);
if (expectedKey != null) {
scan.setStopRow(expectedKey);
}
}
public static final ImmutableBytesWritable UNBOUND = new ImmutableBytesWritable(KeyRange.UNBOUND);
/**
* Return true if the range formed by the lowerInclusiveKey and upperExclusiveKey
* intersects with any of the scan ranges and false otherwise. We cannot pass in
* a KeyRange here, because the underlying compare functions expect lower inclusive
* and upper exclusive keys. We cannot get their next key because the key must
* conform to the row key schema and if a null byte is added to a lower inclusive
* key, it's no longer a valid, real key.
* @param lowerInclusiveKey lower inclusive key
* @param upperExclusiveKey upper exclusive key
* @return true if the scan range intersects with the specified lower/upper key
* range
*/
public boolean intersect(byte[] lowerInclusiveKey, byte[] upperExclusiveKey) {
if (isEverything()) {
return true;
}
if (isDegenerate()) {
return false;
}
return filter.hasIntersect(lowerInclusiveKey, upperExclusiveKey);
}
@Override
public String toString() {
return "ScanRanges[" + ranges.toString() + "]";
}
}