FieldSpans.java

package org.apache.lucene.search.spans;


/**
 * Copyright 2005 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.
 */
import java.util.HashMap;
import java.util.Set;

/**
 * Keeps a record of the matching spans and search terms for each field.
 */
public class FieldSpans 
{
  /** One {@link Entry} per field */
  private HashMap entries = new HashMap();

  /**
   * Record matching spans for a given field.
   *
   * @param field     field that was matched
   * @param spanTotal total number of matching spans (which might be more
   *                  than we're recording if some low-scoring ones dropped
   *                  off the bottom.)
   * @param spans     matching spans
   * @param terms     set of all search terms on this field
   */
  public void recordSpans(String field, int spanTotal, Span[] spans, Set terms) {
    entries.put(field, new Entry(spanTotal, spans, terms));
  }

  /**
   * Add matching spans for one or more fields.
   *
   * @param other     set of matching spans
   */
  public void addSpans(FieldSpans other) {
    entries.putAll(other.entries);
  }

  /** Get a set of all the field names */
  public Set getFields() {
    return entries.keySet();
  }

  /** Retrieve the total number of spans which matched the field */
  public int getSpanTotal(String field) {
    Entry ent = (Entry)entries.get(field);
    return (ent == null) ? 0 : ent.total;
  }

  /** Retrieve the number of spans stored for a given field */
  public int getSpanCount(String field) {
    Entry ent = (Entry)entries.get(field);
    return (ent == null) ? 0 : ent.spans.length;
  }

  /**
   * Retrieve the matching spans for a given field. They are always in
   * increasing position order.
   */
  public Span[] getSpans(String field) {
    Entry ent = (Entry)entries.get(field);
    return (ent == null) ? null : ent.spans;
  }

  /** Retrieve the set of search terms for a given field */
  public Set getTerms(String field) {
    Entry ent = (Entry)entries.get(field);
    return (ent == null) ? null : ent.terms;
  }

  /** true if no spans have yet been stored */
  public boolean isEmpty() {
    return entries.isEmpty();
  }

  /** Stores all the information for a field */
  private class Entry 
  {
    int total;
    Span[] spans;
    Set terms;

    Entry(int total, Span[] spans, Set terms) {
      this.total = total;
      this.spans = spans;
      this.terms = terms;
    }
  }
}