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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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 org.codehaus.groovy.ast.ClassNode;
import java.util.List;
/**
* A MetaClass within Groovy defines the behaviour of any given Groovy or Java class. The MetaClass
* interface defines two parts. The client API, which is defined via the extend MetaObjectProtocol interface
* and the contract with the Groovy runtime system.
*
* In general the compiler and Groovy runtime engine interact with methods on this class whilst MetaClass
* clients interact with the method defined by the MetaObjectProtocol interface
*
* @see MetaClassImpl
* @see groovy.lang.MetaObjectProtocol
*
* @author John Wilson
* @author Graeme Rocher
*/
public interface MetaClass extends MetaObjectProtocol {
/**
* Invokes a method on the given receiver for the specified arguments. The sender is the class that invoked the method on the object.
* The MetaClass will attempt to establish the method to invoke based on the name and arguments provided.
*
*
The isCallToSuper and fromInsideClass help the Groovy runtime perform optimisations on the call to go directly
* to the super class if necessary
*
* @param sender The java.lang.Class instance that invoked the method
* @param receiver The object which the method was invoked on
* @param methodName The name of the method
* @param arguments The arguments to the method
* @param isCallToSuper Whether the method is a call to a super class method
* @param fromInsideClass Whether the call was invoked from the inside or the outside of the class
*
* @return The return value of the method
*/
Object invokeMethod(Class sender, Object receiver, String methodName, Object[] arguments, boolean isCallToSuper, boolean fromInsideClass);
/**
*
Retrieves a property on the given receiver for the specified arguments. The sender is the class that is requesting the property from the object.
* The MetaClass will attempt to establish the method to invoke based on the name and arguments provided.
*
*
The isCallToSuper and fromInsideClass help the Groovy runtime perform optimisations on the call to go directly
* to the super class if necessary
*
* @param sender The java.lang.Class instance that requested the property
* @param receiver The Object which the property is being retrieved from
* @param property The name of the property
* @param isCallToSuper Whether the call is to a super class property
* @param fromInsideClass ??
*
* @return The properties value
*/
Object getProperty(Class sender, Object receiver, String property, boolean isCallToSuper, boolean fromInsideClass);
/**
*
Sets a property on the given receiver for the specified arguments. The sender is the class that is setting the property from the object.
* The MetaClass will attempt to establish the method to invoke based on the name and arguments provided.
*
*
The isCallToSuper and fromInsideClass help the Groovy runtime perform optimisations on the call to go directly
* to the super class if necessary
*
* @param sender The java.lang.Class instance that is mutating the property
* @param receiver The Object which the property is being set on
* @param property The name of the property
* @param value The new value of the property to set
* @param isCallToSuper Whether the call is to a super class property
* @param fromInsideClass Whether the call was invoked from the inside or the outside of the class
*/
void setProperty(Class sender, Object receiver, String property, Object value, boolean isCallToSuper, boolean fromInsideClass);
/**
*
*
Attempts to invoke the methodMissing method otherwise throws a MissingMethodException
*
* @see groovy.lang.MissingMethodException
*
* @param instance The instance to invoke methodMissing on
* @param methodName The name of the method
* @param arguments The arguments to the method
* @return The results of methodMissing or throws MissingMethodException
*/
Object invokeMissingMethod(Object instance, String methodName, Object[] arguments);
/**
* Invokes the propertyMissing method otherwise throws a MissingPropertyException
*
* @param instance The instance of the class
* @param propertyName The name of the property
* @param optionalValue The value of the property which could be null in the case of a getter
* @param isGetter Whether the missing property event was the result of a getter or a setter
*
* @return The result of the propertyMissing method or throws MissingPropertyException
*/
Object invokeMissingProperty(Object instance, String propertyName, Object optionalValue, boolean isGetter);
/**
* Retrieves the value of an attribute (field). This method is to support the Groovy runtime and not for general client API usage.
*
* @param sender The class of the object that requested the attribute
* @param receiver The instance
* @param messageName The name of the attribute
* @param useSuper Whether to look-up on the super class or not
* @return The attribute value
*/
Object getAttribute(Class sender, Object receiver, String messageName, boolean useSuper);
/**
* Sets the value of an attribute (field). This method is to support the Groovy runtime and not for general client API usage.
*
* @param sender The class of the object that requested the attribute
* @param receiver The instance
* @param messageName The name of the attribute
* @param messageValue The value of the attribute
* @param useSuper Whether to look-up on the super class or not
* @param fromInsideClass Whether the call happened from the inside or the outside of a class
*/
void setAttribute(Class sender, Object receiver, String messageName, Object messageValue, boolean useSuper, boolean fromInsideClass);
/**
* Complete the initialisation process. After this method
* is called no methods should be added to the meta class.
* Invocation of methods or access to fields/properties is
* forbidden unless this method is called. This method
* should contain any initialisation code, taking a longer
* time to complete. An example is the creation of the
* Reflector. It is suggested to synchronize this
* method.
*/
void initialize();
/**
* Retrieves a list of MetaProperty instances that the MetaClass has
*
* @see MetaProperty
*
* @return A list of MetaProperty instances
*/
List getProperties();
/**
* Retrieves a list of MetaMethods held by the class. This list does not include MetaMethods added by groovy.lang.ExpandoMetaClass.
*
* @return A list of MetaMethods
*/
List getMethods();
/**
* Obtains a reference to the original AST for the MetaClass if it is available at runtime
*
* @return The original AST or null if it cannot be returned
*/
ClassNode getClassNode();
/**
* Retrieves a list of MetaMethods held by this class. This list includes MetaMethods added by groovy.lang.ExpandoMetaClass.
*
* @return A list of MetaMethods
*/
List getMetaMethods();
/**
*
* Internal method to support Groovy runtime. Not for client usage.
*
* @param numberOfConstructors The number of constructors
* @param arguments The arguments
*
* @return selected index
*/
int selectConstructorAndTransformArguments(int numberOfConstructors, Object[] arguments);
/**
* Selects a method by name and argument classes. This method
* does not search for an exact match, it searches for a compatible
* method. For this the method selection mechanism is used as provided
* by the implementation of this MetaClass. pickMethod may or may
* not be used during the method selection process when invoking a method.
* There is no warranty for that.
*
* @return a matching MetaMethod or null
* @throws GroovyRuntimeException if there is more than one matching method
* @param methodName the name of the method to pick
* @param arguments the method arguments
*/
MetaMethod pickMethod(String methodName, Class[] arguments);
}