| /* |
| * 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.scxml2; |
| |
| /** |
| * Interface for a component that may be used by the SCXML engines to |
| * evaluate the expressions within the SCXML document. |
| * |
| */ |
| public interface Evaluator { |
| |
| /** SCXML 1.0 Null Data Model name **/ |
| String NULL_DATA_MODEL = "null"; |
| |
| /** SCXML 1.0 ECMAScript Data Model name **/ |
| String ECMASCRIPT_DATA_MODEL = "ecmascript"; |
| |
| /** Default Data Model name **/ |
| String DEFAULT_DATA_MODEL = ""; |
| |
| /** |
| * The allowable types of <assign/> including and in particular when using XPath |
| */ |
| enum AssignType { |
| |
| REPLACE_CHILDREN("replacechildren"), |
| FIRST_CHILD("firstchild"), |
| LAST_CHILD("lastchild"), |
| PREVIOUS_SIBLING("previoussibling"), |
| NEXT_SIBLING("nextsibling"), |
| REPLACE("replace"), |
| DELETE("delete"), |
| ADD_ATTRIBUTE("addattribute"); |
| |
| private final String value; |
| |
| private AssignType(String value) { |
| this.value = value; |
| } |
| |
| public String value() { |
| return value; |
| } |
| |
| public static AssignType fromValue(String value) { |
| for (AssignType type : AssignType.values()) { |
| if (type.value().equals(value)) { |
| return type; |
| } |
| } |
| return null; |
| } |
| } |
| |
| /** |
| * Get the datamodel type supported by this Evaluator |
| * @return The supported datamodel type |
| */ |
| String getSupportedDatamodel(); |
| |
| /** |
| * @param data data to be cloned |
| * @return A deep clone of the data |
| */ |
| Object cloneData(Object data); |
| |
| /** |
| * Evaluate an expression returning a data value |
| * |
| * @param ctx variable context |
| * @param expr expression |
| * @return the result of the evaluation |
| * @throws SCXMLExpressionException A malformed expression exception |
| */ |
| Object eval(Context ctx, String expr) |
| throws SCXMLExpressionException; |
| |
| /** |
| * Evaluate a condition. |
| * Manifests as "cond" attributes of <transition>, |
| * <if> and <elseif> elements. |
| * |
| * @param ctx variable context |
| * @param expr expression |
| * @return true/false |
| * @throws SCXMLExpressionException A malformed expression exception |
| */ |
| Boolean evalCond(Context ctx, String expr) |
| throws SCXMLExpressionException; |
| |
| /** |
| * Assigns data to a location |
| * |
| * @param ctx variable context |
| * @param location location expression |
| * @param data the data to assign. |
| * @param type the type of assignment to perform, null assumes {@link AssignType#REPLACE_CHILDREN} |
| * @param attr the name of the attribute to add when using type {@link AssignType#ADD_ATTRIBUTE} |
| * @throws SCXMLExpressionException A malformed expression exception |
| */ |
| void evalAssign(Context ctx, String location, Object data, AssignType type, String attr) |
| throws SCXMLExpressionException; |
| |
| /** |
| * Evaluate a script. |
| * Manifests as <script> element. |
| * |
| * @param ctx variable context |
| * @param script The script |
| * @return The result of the script execution. |
| * @throws SCXMLExpressionException A malformed script |
| */ |
| Object evalScript(Context ctx, String script) |
| throws SCXMLExpressionException; |
| |
| /** |
| * Create a new child context. |
| * |
| * @param parent parent context |
| * @return new child context |
| */ |
| Context newContext(Context parent); |
| |
| } |
| |