/* * Copyright 2004 The Apache Software Foundation * * Licensed 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; using IndexReader = Lucene.Net.Index.IndexReader; namespace Lucene.Net.Search.Spans { /// Matches spans near the beginning of a Field. [Serializable] public class SpanFirstQuery:SpanQuery { private class AnonymousClassSpans : Spans { public AnonymousClassSpans(Lucene.Net.Index.IndexReader reader, SpanFirstQuery enclosingInstance) { InitBlock(reader, enclosingInstance); } private void InitBlock(Lucene.Net.Index.IndexReader reader, SpanFirstQuery enclosingInstance) { this.reader = reader; this.enclosingInstance = enclosingInstance; spans = Enclosing_Instance.match.GetSpans(reader); } private Lucene.Net.Index.IndexReader reader; private SpanFirstQuery enclosingInstance; public SpanFirstQuery Enclosing_Instance { get { return enclosingInstance; } } private Spans spans; public virtual bool Next() { while (spans.Next()) { // scan to next match if (End() <= Enclosing_Instance.end) return true; } return false; } public virtual bool SkipTo(int target) { if (!spans.SkipTo(target)) return false; if (spans.End() <= Enclosing_Instance.end) // there is a match return true; return Next(); // scan to next match } public virtual int Doc() { return spans.Doc(); } public virtual int Start() { return spans.Start(); } public virtual int End() { return spans.End(); } public override System.String ToString() { return "spans(" + Enclosing_Instance.ToString() + ")"; } } private SpanQuery match; private int end; /// Construct a SpanFirstQuery matching spans in match whose end /// position is less than or equal to end. /// public SpanFirstQuery(SpanQuery match, int end) { this.match = match; this.end = end; } /// Return the SpanQuery whose matches are filtered. public virtual SpanQuery GetMatch() { return match; } /// Return the maximum end position permitted in a match. public virtual int GetEnd() { return end; } public override System.String GetField() { return match.GetField(); } public override System.Collections.ICollection GetTerms() { return match.GetTerms(); } public override System.String ToString(System.String field) { System.Text.StringBuilder buffer = new System.Text.StringBuilder(); buffer.Append("spanFirst("); buffer.Append(match.ToString(field)); buffer.Append(", "); buffer.Append(end); buffer.Append(")"); return buffer.ToString(); } public override Spans GetSpans(IndexReader reader) { return new AnonymousClassSpans(reader, this); } } }