/*
* 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.analysis.util;
import java.util.Map;
import java.util.Set;
import org.apache.lucene.analysis.TokenStream;
/**
* Abstract parent class for analysis factories that create {@link org.apache.lucene.analysis.TokenFilter}
* instances.
*/
public abstract class TokenFilterFactory extends AbstractAnalysisFactory {
private static final AnalysisSPILoader<TokenFilterFactory> loader =
new AnalysisSPILoader<>(TokenFilterFactory.class,
new String[] { "TokenFilterFactory", "FilterFactory" });
/** looks up a tokenfilter by name from context classpath */
public static TokenFilterFactory forName(String name, Map<String,String> args) {
return loader.newInstance(name, args);
}
/** looks up a tokenfilter class by name from context classpath */
public static Class<? extends TokenFilterFactory> lookupClass(String name) {
return loader.lookupClass(name);
}
/** returns a list of all available tokenfilter names from context classpath */
public static Set<String> availableTokenFilters() {
return loader.availableServices();
}
/**
* Reloads the factory list from the given {@link ClassLoader}.
* Changes to the factories are visible after the method ends, all
* iterators ({@link #availableTokenFilters()},...) stay consistent.
*
* <p><b>NOTE:</b> Only new factories are added, existing ones are
* never removed or replaced.
*
* <p><em>This method is expensive and should only be called for discovery
* of new factories on the given classpath/classloader!</em>
*/
public static void reloadTokenFilters(ClassLoader classloader) {
loader.reload(classloader);
}
/**
* Initialize this factory via a set of key-value pairs.
*/
protected TokenFilterFactory(Map<String,String> args) {
super(args);
}
/** Transform the specified input TokenStream */
public abstract TokenStream create(TokenStream input);
}