| /* |
| * 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.Objects; |
| |
| import javax.script.ScriptEngine; |
| import javax.script.ScriptEngineManager; |
| |
| import org.apache.commons.text.StringSubstitutor; |
| |
| /** |
| * Executes the script with the given engine name. |
| * <p> |
| * Execute the script with the engine name in the format "EngineName:Script". |
| * </p> |
| * <p> |
| * For example: {@code "javascript:3 + 4"}. |
| * </p> |
| * <p> |
| * Using a {@link StringSubstitutor}: |
| * </p> |
| * <pre> |
| * StringSubstitutor.createInterpolator().replace("${script:javascript:3 + 4}")); |
| * </pre> |
| * @since 1.5 |
| */ |
| final class ScriptStringLookup extends AbstractStringLookup { |
| |
| /** |
| * Defines the singleton for this class. |
| */ |
| static final ScriptStringLookup INSTANCE = new ScriptStringLookup(); |
| |
| /** |
| * No need to build instances for now. |
| */ |
| private ScriptStringLookup() { |
| // empty |
| } |
| |
| /** |
| * Execute the script with the engine name in the format "EngineName:Script". |
| * Extra colons will be ignored. |
| * <p> |
| * For example: {@code "javascript:3 + 4"}. |
| * </p> |
| * |
| * @param key |
| * the engine:script to execute, may be null |
| * @return The value returned by the execution. |
| */ |
| @Override |
| public String lookup(final String key) { |
| if (key == null) { |
| return null; |
| } |
| final String[] keys = key.split(SPLIT_STR, 2); |
| final int keyLen = keys.length; |
| if (keyLen != 2) { |
| throw IllegalArgumentExceptions.format("Bad script key format [%s]; expected format is EngineName:Script.", |
| key); |
| } |
| final String engineName = keys[0]; |
| final String script = keys[1]; |
| try { |
| final ScriptEngine scriptEngine = new ScriptEngineManager().getEngineByName(engineName); |
| if (scriptEngine == null) { |
| throw new IllegalArgumentException("No script engine named " + engineName); |
| } |
| return Objects.toString(scriptEngine.eval(script), null); |
| } catch (final Exception e) { |
| throw IllegalArgumentExceptions.format(e, "Error in script engine [%s] evaluating script [%s].", engineName, |
| script); |
| } |
| } |
| |
| } |