| /* |
| * 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.iterate; |
| |
| import java.sql.SQLException; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Set; |
| |
| import org.apache.hadoop.hbase.io.ImmutableBytesWritable; |
| import org.apache.phoenix.compile.ColumnProjector; |
| import org.apache.phoenix.compile.RowProjector; |
| import org.apache.phoenix.expression.Expression; |
| import org.apache.phoenix.expression.aggregator.Aggregator; |
| import org.apache.phoenix.schema.tuple.Tuple; |
| |
| import com.google.common.collect.Iterators; |
| import com.google.common.collect.Sets; |
| |
| /** |
| * Result scanner that dedups the incoming tuples to make them distinct. |
| * <p> |
| * Note that the results are held in memory |
| * |
| * |
| * @since 1.2 |
| */ |
| public class DistinctAggregatingResultIterator implements AggregatingResultIterator { |
| private final AggregatingResultIterator delegate; |
| private final RowProjector rowProjector; |
| private Iterator<ResultEntry> resultIterator; |
| private final ImmutableBytesWritable ptr1 = new ImmutableBytesWritable(); |
| private final ImmutableBytesWritable ptr2 = new ImmutableBytesWritable(); |
| |
| private class ResultEntry { |
| private final int hashCode; |
| private final Tuple result; |
| |
| ResultEntry(Tuple result) { |
| final int prime = 31; |
| this.result = result; |
| int hashCode = 0; |
| for (ColumnProjector column : rowProjector.getColumnProjectors()) { |
| Expression e = column.getExpression(); |
| if (e.evaluate(this.result, ptr1)) { |
| hashCode = prime * hashCode + ptr1.hashCode(); |
| } |
| } |
| this.hashCode = hashCode; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o == this) { |
| return true; |
| } |
| if (o == null) { |
| return false; |
| } |
| if (o.getClass() != this.getClass()) { |
| return false; |
| } |
| ResultEntry that = (ResultEntry) o; |
| for (ColumnProjector column : rowProjector.getColumnProjectors()) { |
| Expression e = column.getExpression(); |
| boolean isNull1 = !e.evaluate(this.result, ptr1); |
| boolean isNull2 = !e.evaluate(that.result, ptr2); |
| if (isNull1 && isNull2) { |
| return true; |
| } |
| if (isNull1 || isNull2) { |
| return false; |
| } |
| if (ptr1.compareTo(ptr2) != 0) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public int hashCode() { |
| return hashCode; |
| } |
| |
| Tuple getResult() { |
| return result; |
| } |
| } |
| |
| protected ResultIterator getDelegate() { |
| return delegate; |
| } |
| |
| public DistinctAggregatingResultIterator(AggregatingResultIterator delegate, |
| RowProjector rowProjector) { |
| this.delegate = delegate; |
| this.rowProjector = rowProjector; |
| } |
| |
| @Override |
| public Tuple next() throws SQLException { |
| Iterator<ResultEntry> iterator = getResultIterator(); |
| if (iterator.hasNext()) { |
| ResultEntry entry = iterator.next(); |
| Tuple tuple = entry.getResult(); |
| aggregate(tuple); |
| return tuple; |
| } |
| resultIterator = Iterators.emptyIterator(); |
| return null; |
| } |
| |
| private Iterator<ResultEntry> getResultIterator() throws SQLException { |
| if (resultIterator != null) { |
| return resultIterator; |
| } |
| |
| Set<ResultEntry> entries = Sets.<ResultEntry>newHashSet(); // TODO: size? |
| try { |
| for (Tuple result = delegate.next(); result != null; result = delegate.next()) { |
| ResultEntry entry = new ResultEntry(result); |
| entries.add(entry); |
| } |
| } finally { |
| delegate.close(); |
| } |
| |
| resultIterator = entries.iterator(); |
| return resultIterator; |
| } |
| |
| @Override |
| public void close() { |
| resultIterator = Iterators.emptyIterator(); |
| } |
| |
| |
| @Override |
| public void explain(List<String> planSteps) { |
| delegate.explain(planSteps); |
| planSteps.add("CLIENT DISTINCT ON " + rowProjector.toString()); |
| } |
| |
| @Override |
| public Aggregator[] aggregate(Tuple result) { |
| return delegate.aggregate(result); |
| } |
| |
| @Override |
| public String toString() { |
| return "DistinctAggregatingResultIterator [delegate=" + delegate |
| + ", rowProjector=" + rowProjector + ", resultIterator=" |
| + resultIterator + ", ptr1=" + ptr1 + ", ptr2=" + ptr2 + "]"; |
| } |
| } |