/*
* 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.accumulo.core.iterators;
import java.io.IOException;
import java.util.Collection;
import java.util.Map;
import org.apache.accumulo.core.data.ByteSequence;
import org.apache.accumulo.core.data.Key;
import org.apache.accumulo.core.data.Range;
import org.apache.accumulo.core.data.Value;
/**
* A SortedKeyValueIterator similar to {@link org.apache.accumulo.core.iterators.ServerFilter} but with the implemented methods marked as synchronized. The
* {@link #init(SortedKeyValueIterator, Map, IteratorEnvironment)} method is also not supported since the source can only be assigned in the constructor.
*
* @since 2.0
*/
public abstract class SynchronizedServerFilter implements SortedKeyValueIterator<Key,Value> {
protected final SortedKeyValueIterator<Key,Value> source;
public SynchronizedServerFilter(SortedKeyValueIterator<Key,Value> source) {
this.source = source;
}
@Override
public abstract SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env);
@Override
public synchronized void next() throws IOException {
source.next();
findTop();
}
@Override
public synchronized void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive) throws IOException {
source.seek(range, columnFamilies, inclusive);
findTop();
}
@Override
public synchronized Key getTopKey() {
return source.getTopKey();
}
@Override
public synchronized Value getTopValue() {
return source.getTopValue();
}
@Override
public synchronized boolean hasTop() {
return source.hasTop();
}
/**
* Iterates over the source until an acceptable key/value pair is found.
*/
private void findTop() throws IOException {
while (source.hasTop()) {
Key top = source.getTopKey();
if (top.isDeleted() || (accept(top, source.getTopValue()))) {
break;
}
source.next();
}
}
/**
* @return <tt>true</tt> if the key/value pair is accepted by the filter.
*/
protected abstract boolean accept(Key k, Value v);
@Override
public void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env) throws IOException {
throw new UnsupportedOperationException();
}
}