Java tutorial
/* * 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. */ package org.apache.lucene.facet; import java.io.IOException; import java.util.List; /** Common base class for all facets implementations. * * @lucene.experimental */ public abstract class Facets { /** Default constructor. */ public Facets() { } /** Returns the topN child labels under the specified * path. Returns null if the specified path doesn't * exist or if this dimension was never seen. */ public abstract FacetResult getTopChildren(int topN, String dim, String... path) throws IOException; /** Return the count or value * for a specific path. Returns -1 if * this path doesn't exist, else the count. */ public abstract Number getSpecificValue(String dim, String... path) throws IOException; /** Returns topN labels for any dimension that had hits, * sorted by the number of hits that dimension matched; * this is used for "sparse" faceting, where many * different dimensions were indexed, for example * depending on the type of document. */ public abstract List<FacetResult> getAllDims(int topN) throws IOException; }