/*
* 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.system;
import java.io.IOException;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
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;
import org.apache.accumulo.core.iterators.IteratorEnvironment;
import org.apache.accumulo.core.iterators.SortedKeyValueIterator;
public class EmptyIterator implements InterruptibleIterator {
public static final EmptyIterator EMPTY_ITERATOR = new EmptyIterator();
@Override
public void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env) throws IOException {}
@Override
public boolean hasTop() {
return false;
}
@Override
public void next() throws IOException {
// nothing should call this since hasTop always returns false
throw new UnsupportedOperationException();
}
@Override
public void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive) throws IOException {}
@Override
public Key getTopKey() {
// nothing should call this since hasTop always returns false
throw new UnsupportedOperationException();
}
@Override
public Value getTopValue() {
// nothing should call this since hasTop always returns false
throw new UnsupportedOperationException();
}
@Override
public SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env) {
return EMPTY_ITERATOR;
}
@Override
public void setInterruptFlag(AtomicBoolean flag) {}
}