/*
* 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.
*/
using System;
namespace Lucene.Net.Search
{
/// This abstract class defines methods to iterate over a set of non-decreasing
/// doc ids. Note that this class assumes it iterates on doc Ids, and therefore
/// is set to Int32.MaxValue in order to be used as
/// a sentinel object. Implementations of this class are expected to consider
/// as an invalid value.
///
public abstract class DocIdSetIterator
{
// TODO (3.0): review the javadocs and remove any references to '3.0'.
private int doc = - 1;
/// When returned by , and
/// it means there are no more docs in the iterator.
///
public static readonly int NO_MORE_DOCS = System.Int32.MaxValue;
/// Unsupported anymore. Call instead. This method throws
/// if called.
///
///
/// use instead.
///
[Obsolete("use DocID() instead.")]
public virtual int Doc()
{
throw new System.NotSupportedException("Call docID() instead.");
}
/// Returns the following:
///
/// - -1 or if or
/// were not called yet.
/// - if the iterator has exhausted.
/// - Otherwise it should return the doc ID it is currently on.
///
///
/// NOTE: in 3.0, this method will become abstract.
///
///
/// 2.9
///
public virtual int DocID()
{
return doc;
}
/// Unsupported anymore. Call instead. This method throws
/// if called.
///
///
/// use instead. This will be removed in 3.0
///
[Obsolete("use NextDoc() instead. This will be removed in 3.0")]
public virtual bool Next()
{
throw new System.NotSupportedException("Call nextDoc() instead.");
}
/// Unsupported anymore. Call instead. This method throws
/// if called.
///
///
/// use instead. This will be removed in 3.0
///
[Obsolete("use Advance(int) instead. This will be removed in 3.0")]
public virtual bool SkipTo(int target)
{
throw new System.NotSupportedException("Call advance() instead.");
}
/// Advances to the next document in the set and returns the doc it is
/// currently on, or if there are no more docs in the
/// set.
///
/// NOTE: in 3.0 this method will become abstract, following the removal
/// of . For backward compatibility it is implemented as:
///
///
/// public int nextDoc() throws IOException {
/// return next() ? doc() : NO_MORE_DOCS;
/// }
///
///
/// NOTE: after the iterator has exhausted you should not call this
/// method, as it may result in unpredicted behavior.
///
///
/// 2.9
///
public virtual int NextDoc()
{
return doc = Next()?Doc():NO_MORE_DOCS;
}
/// Advances to the first beyond the current whose document number is greater
/// than or equal to target. Returns the current document number or
/// if there are no more docs in the set.
///
/// Behaves as if written:
///
///
/// int advance(int target) {
/// int doc;
/// while ((doc = nextDoc()) < target) {
/// }
/// return doc;
/// }
///
///
/// Some implementations are considerably more efficient than that.
///
/// NOTE: certain implemenations may return a different value (each
/// time) if called several times in a row with the same target.
///
/// NOTE: this method may be called with for
/// efficiency by some Scorers. If your implementation cannot efficiently
/// determine that it should exhaust, it is recommended that you check for that
/// value in each call to this method.
///
/// NOTE: after the iterator has exhausted you should not call this
/// method, as it may result in unpredicted behavior.
///
/// NOTE: in 3.0 this method will become abstract, following the removal
/// of .
///
///
/// 2.9
///
public virtual int Advance(int target)
{
if (target == NO_MORE_DOCS)
{
return doc = NO_MORE_DOCS;
}
return doc = SkipTo(target)?Doc():NO_MORE_DOCS;
}
}
}