/*
* 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.taxonomy.writercache;
import org.apache.lucene.facet.taxonomy.FacetLabel;
/**
* Abstract class for storing Label->Ordinal mappings in a taxonomy.
*
* @lucene.experimental
*/
public abstract class LabelToOrdinal {
/** How many ordinals we've seen. */
protected int counter;
/** Returned by {@link #getOrdinal} when the label isn't
* recognized. */
public static final int INVALID_ORDINAL = -2;
/** Default constructor. */
public LabelToOrdinal() {
}
/**
* return the maximal Ordinal assigned so far
*/
public int getMaxOrdinal() {
return this.counter;
}
/**
* Returns the next unassigned ordinal. The default behavior of this method
* is to simply increment a counter.
*/
public int getNextOrdinal() {
return this.counter++;
}
/**
* Adds a new label if its not yet in the table.
* Throws an {@link IllegalArgumentException} if the same label with
* a different ordinal was previoulsy added to this table.
*/
public abstract void addLabel(FacetLabel label, int ordinal);
/**
* Returns the ordinal assigned to the given label,
* or {@link #INVALID_ORDINAL} if the label cannot be found in this table.
*/
public abstract int getOrdinal(FacetLabel label);
}