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/*
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 *  or more contributor license agreements.  See the NOTICE file
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 *  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
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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); }





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