com.groupbyinc.common.apache.commons.text.lookup.MapStringLookup Maven / Gradle / Ivy
/*
* 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.commons.text.lookup;
import java.util.Map;
/**
* A map-based lookup where the request for a lookup is answered with the value for that key.
*
* @param
* A map's value type
*
* @since 1.3
*/
final class MapStringLookup implements StringLookup {
/**
* Creates a new instance backed by a Map. Used by the default lookup.
*
* @param
* the map's value type.
* @param map
* the map of keys to values, may be null.
* @return a new instance backed by the given map.
*/
static MapStringLookup on(final Map map) {
return new MapStringLookup<>(map);
}
/**
* Map keys are variable names and value.
*/
private final Map map;
/**
* Creates a new instance backed by a Map. Used by the default lookup.
*
* @param map
* the map of keys to values, may be null.
*/
private MapStringLookup(final Map map) {
this.map = map;
}
/**
* Gets the map used in lookups.
*
* @return the map used in lookups.
*/
Map getMap() {
return map;
}
/**
* Looks up a String key to a String value using the map.
*
* If the map is null, then null is returned. The map result object is converted to a string using toString().
*
*
* @param key
* the key to be looked up, may be null.
* @return the matching value, null if no match
*/
@Override
public String lookup(final String key) {
if (map == null) {
return null;
}
final V obj;
try {
obj = map.get(key);
} catch (final NullPointerException e) {
// Could be a ConcurrentHashMap and a null key request
return null;
}
return obj != null ? obj.toString() : null;
}
@Override
public String toString() {
return getClass().getName() + " [map=" + map + "]";
}
}