groovy.lang.Binding 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 groovy.lang;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* Represents the variable bindings of a script which can be altered
* from outside the script object or created outside of a script and passed
* into it.
* Binding instances are not supposed to be used in a multi-threaded context.
*
* @author James Strachan
*/
public class Binding extends GroovyObjectSupport {
private Map variables;
public Binding() {
}
public Binding(Map variables) {
this.variables = variables;
}
/**
* A helper constructor used in main(String[]) method calls
*
* @param args are the command line arguments from a main()
*/
public Binding(String[] args) {
this();
setVariable("args", args);
}
/**
* @param name the name of the variable to lookup
* @return the variable value
*/
public Object getVariable(String name) {
if (variables == null)
throw new MissingPropertyException(name, this.getClass());
Object result = variables.get(name);
if (result == null && !variables.containsKey(name)) {
throw new MissingPropertyException(name, this.getClass());
}
return result;
}
/**
* Sets the value of the given variable
*
* @param name the name of the variable to set
* @param value the new value for the given variable
*/
public void setVariable(String name, Object value) {
if (variables == null)
variables = new LinkedHashMap();
variables.put(name, value);
}
/**
* Simple check for whether the binding contains a particular variable or not.
*
* @param name the name of the variable to check for
*/
public boolean hasVariable(String name) {
return variables != null && variables.containsKey(name);
}
public Map getVariables() {
if (variables == null)
variables = new LinkedHashMap();
return variables;
}
/**
* Overloaded to make variables appear as bean properties or via the subscript operator
*/
public Object getProperty(String property) {
/** @todo we should check if we have the property with the metaClass instead of try/catch */
try {
return super.getProperty(property);
}
catch (MissingPropertyException e) {
return getVariable(property);
}
}
/**
* Overloaded to make variables appear as bean properties or via the subscript operator
*/
public void setProperty(String property, Object newValue) {
/** @todo we should check if we have the property with the metaClass instead of try/catch */
try {
super.setProperty(property, newValue);
}
catch (MissingPropertyException e) {
setVariable(property, newValue);
}
}
}