| /* |
| * 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.function.BiFunction; |
| import java.util.function.Function; |
| |
| /** |
| * Lookups a String key for a String value. |
| * <p> |
| * This class represents the simplest form of a string to string map. It has a benefit over a map in that it can create |
| * the result on demand based on the key. |
| * </p> |
| * <p> |
| * For example, it would be possible to implement a lookup that used the key as a primary key, and looked up the value |
| * on demand from the database. |
| * </p> |
| * <p> |
| * Like {@link BiFunction} is a variant of {@link Function}, this {@code BiStringLookup} is a variant of |
| * {@link StringLookup}. |
| * </p> |
| * |
| * @param <U> The second argument type. |
| * |
| * @since 1.9 |
| */ |
| @FunctionalInterface |
| public interface BiStringLookup<U> extends StringLookup { |
| |
| /** |
| * Looks up a String key to provide a String value. |
| * <p> |
| * The internal implementation may use any mechanism to return the value. The simplest implementation is to use a |
| * Map. However, virtually any implementation is possible. |
| * </p> |
| * <p> |
| * For example, it would be possible to implement a lookup that used the key as a primary key, and looked up the |
| * value on demand from the database Or, a numeric based implementation could be created that treats the key as an |
| * integer, increments the value and return the result as a string - converting 1 to 2, 15 to 16 etc. |
| * </p> |
| * <p> |
| * This method always returns a String, regardless of the underlying data, by converting it as necessary. For |
| * example: |
| * </p> |
| * |
| * <pre> |
| * Map<String, Object> map = new HashMap<String, Object>(); |
| * map.put("number", new Integer(2)); |
| * assertEquals("2", StringLookupFactory.biFunctionStringLookup(map).lookup("number", "A context object")); |
| * </pre> |
| * |
| * @param key the key to look up, may be null. |
| * @param object ignored by default. |
| * @return The matching value, null if no match. |
| */ |
| default String lookup(final String key, final U object) { |
| return lookup(key); |
| } |
| |
| } |