com.hazelcast.org.apache.calcite.runtime.EnumeratorCursor 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 com.hazelcast.com.liance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.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 com.hazelcast.org.apache.calcite.runtime;
import com.hazelcast.org.apache.calcite.avatica.util.PositionedCursor;
import com.hazelcast.org.apache.calcite.linq4j.Enumerator;
/**
* Implementation of {@link com.hazelcast.org.apache.calcite.avatica.util.Cursor} on top of an
* {@link com.hazelcast.org.apache.calcite.linq4j.Enumerator} that
* returns a record for each row. The returned record is cached to avoid
* multiple com.hazelcast.com.utations of current row.
* For instance,
* {@link com.hazelcast.org.apache.calcite.adapter.enumerable.EnumerableCalc}
* com.hazelcast.com.utes result just in {@code current()} method, thus it makes sense to
* cache the result and make it available for all the accessors.
*
* @param Element type
*/
public abstract class EnumeratorCursor extends PositionedCursor {
private final Enumerator enumerator;
/**
* Creates a {@code EnumeratorCursor}
* @param enumerator input enumerator
*/
protected EnumeratorCursor(Enumerator enumerator) {
this.enumerator = enumerator;
}
protected T current() {
return enumerator.current();
}
public boolean next() {
return enumerator.moveNext();
}
public void close() {
enumerator.close();
}
}