io.github.microcks.util.el.EvaluationContext Maven / Gradle / Ivy
/*
* Licensed to Laurent Broudoux (the "Author") under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Author 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 io.github.microcks.util.el;
import io.github.microcks.util.el.function.ELFunction;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* A context used during evaluation of EL expressions. Can be used to register functions,
* store input variables or intermediary results.
* @author laurent
*/
public class EvaluationContext {
private final Map variables = new ConcurrentHashMap<>();
/**
* Put a variable into this context
* @param name The name of variable
* @param value The variable itself
*/
public void setVariable(String name, Object value) {
variables.put(name, value);
}
/**
* Put a set of variables into this context
* @param variables key/value pairs for variables names and their values
*/
public void setVariables(Map variables) {
variables.forEach(this::setVariable);
}
/**
* Retrieve a registered variable by it's name.
* @param name The name of variable to look for
* @return The variable having this name or null if no variable.
*/
public Object lookupVariable(String name) {
return variables.get(name);
}
/**
* Register a function using a name and the ELFunction class.
* @param name The name of function to register
* @param function The class representing the function
* @param Any implementation of {@code ELFunction} interface
*/
public void registerFunction(String name, Class function) {
this.variables.put(name, function);
}
/**
* Retrieve a registered function by it's name.
* @param name The name of function to look for
* @param Any implementation of {@code ELFunction} interface
* @return The Function class object
*/
@SuppressWarnings("unchecked")
public Class lookupFunction(String name) {
Object function = variables.get(name);
if (function instanceof Class) {
Class functionClazz = (Class) function;
if (ELFunction.class.isAssignableFrom(functionClazz)) {
return (Class) functionClazz;
}
}
return null;
}
}