Lucene example source code file (SetBasedFieldSelector.java)

This example Lucene source code file (SetBasedFieldSelector.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

fieldselector, fieldselector, fieldselectorresult, fieldselectorresult, set, set, setbasedfieldselector, setbasedfieldselector, util

The Lucene SetBasedFieldSelector.java source code

package org.apache.lucene.document;

import java.util.Set;
/**
 * 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.
 */

/**
 * Declare what fields to load normally and what fields to load lazily
 *
 **/
public class SetBasedFieldSelector implements FieldSelector {
  
  private Set<String> fieldsToLoad;
  private Set<String> lazyFieldsToLoad;
  
  /**
   * Pass in the Set of {@link Field} names to load and the Set of {@link Field} names to load lazily.  If both are null, the
   * Document will not have any {@link Field} on it.  
   * @param fieldsToLoad A Set of {@link String} field names to load.  May be empty, but not null
   * @param lazyFieldsToLoad A Set of {@link String} field names to load lazily.  May be empty, but not null  
   */
  public SetBasedFieldSelector(Set<String> fieldsToLoad, Set lazyFieldsToLoad) {
    this.fieldsToLoad = fieldsToLoad;
    this.lazyFieldsToLoad = lazyFieldsToLoad;
  }

  /**
   * Indicate whether to load the field with the given name or not. If the {@link Field#name()} is not in either of the 
   * initializing Sets, then {@link org.apache.lucene.document.FieldSelectorResult#NO_LOAD} is returned.  If a Field name
   * is in both <code>fieldsToLoad and lazyFieldsToLoad, lazy has precedence.
   * 
   * @param fieldName The {@link Field} name to check
   * @return The {@link FieldSelectorResult}
   */
  public FieldSelectorResult accept(String fieldName) {
    FieldSelectorResult result = FieldSelectorResult.NO_LOAD;
    if (fieldsToLoad.contains(fieldName) == true){
      result = FieldSelectorResult.LOAD;
    }
    if (lazyFieldsToLoad.contains(fieldName) == true){
      result = FieldSelectorResult.LAZY_LOAD;
    }                                           
    return result;
  }
}