content: /*
   * MethodContact.java April 2007
   *
   * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
   *
   * Licensed 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 com.aliyun.odps.simpleframework.xml.core;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Method;
  
  /**
   * The <code>MethodContact</code> object is acts as a contact that
   * can set and get data to and from an object using methods. This 
   * requires a get method and a set method that share the same class
   * type for the return and parameter respectively.
   *
   * @author Niall Gallagher
   *
   * @see MethodScanner
   */ 
  class MethodContact implements Contact {
     
     /**
      * This is the label that marks both the set and get methods.
      */         
     private Annotation label;
     
     /**
      * This is the set method which is used to set the value.
      */ 
     private MethodPart set;
     
     /**
      * This is the get method which is used to get the value.
      */
     private MethodPart get;
  
     /**
      * This is the dependent types as taken from the get method.
      */
     private Class[] items;
     
     /**
      * This represents the declaring class for this method.
      */
     private Class owner;
     
     /**
      * This is the dependent type as taken from the get method.
      */
     private Class item;
     
     /**
      * This is the type associated with this point of contact.
      */ 
     private Class type; 
     
     /**
      * This represents the name of the method for this contact.
      */
     private String name;
     
     /**
      * Constructor for the <code>MethodContact</code> object. This is
      * used to compose a point of contact that makes use of a get and
      * set method on a class. The specified methods will be invoked
      * during the serialization process to get and set values.
      *
      * @param get this forms the get method for the object
      */ 
     public MethodContact(MethodPart get) {
        this(get, null);
     }
     
     /**
      * Constructor for the <code>MethodContact</code> object. This is
      * used to compose a point of contact that makes use of a get and
      * set method on a class. The specified methods will be invoked
      * during the serialization process to get and set values.
      *
      * @param get this forms the get method for the object
      * @param set this forms the get method for the object 
      */ 
     public MethodContact(MethodPart get, MethodPart set) {
        this.owner = get.getDeclaringClass();
        this.label = get.getAnnotation();   
        this.items = get.getDependents();
        this.item = get.getDependent();
        this.type = get.getType();   
        this.name = get.getName();
        this.set = set;
        this.get = get;
     }  
     
     /**
      * This is used to determine if the annotated contact is for a
      * read only variable. A read only variable is a field that
      * can be set from within the constructor such as a blank final
      * variable. It can also be a method with no set counterpart.
      * 
      * @return this returns true if the contact is a constant one
      */
     public boolean isReadOnly() {
        return set == null;
     }
     
     /**
      * This returns the get part of the method. Acquiring separate
      * parts of the method ensures that method parts can be inherited
      * easily between types as overriding either part of a property.
      * 
      * @return this returns the get part of the method contact
      */
     public MethodPart getRead() {
        return get;
     }
     
     /**
      * This returns the set part of the method. Acquiring separate
      * parts of the method ensures that method parts can be inherited
      * easily between types as overriding either part of a property.
      * 
      * @return this returns the set part of the method contact
      */
     public MethodPart getWrite() {
        return set;
     }
     
     /**
      * This is the annotation associated with the point of contact.
      * This will be an XML annotation that describes how the contact
      * should be serialized and deserialized from the object.
      *
      * @return this provides the annotation associated with this
      */
     public Annotation getAnnotation() {
        return label;
     }
     
     /**
      * This is the annotation associated with the point of contact.
      * This will be an XML annotation that describes how the contact
      * should be serialized and deserialized from the object.
      * 
      * @param type this is the type of the annotation to acquire
      *
      * @return this provides the annotation associated with this
      */
     public <T extends Annotation> T getAnnotation(Class<T> type) {
        T result = get.getAnnotation(type);
        
        if(type == label.annotationType()) {
           return (T) label;
        }
        if(result == null && set != null) {        
           return set.getAnnotation(type);
        }
        return result;
     }
  
     /**
      * This will provide the contact type. The contact type is the
      * class that is to be set and get on the object. This represents
      * the return type for the get and the parameter for the set.
      *
      * @return this returns the type that this contact represents
      */
     public Class getType() {
        return type;
     }
     
     /**
      * This provides the dependent class for the contact. This will
      * actually represent a generic type for the actual type. For
      * contacts that use a <code>Collection</code> type this will
      * be the generic type parameter for that collection.
      * 
      * @return this returns the dependent type for the contact
      */
     public Class getDependent() {
        return item;
     }
     
     /**
      * This provides the dependent classes for the contact. This will
      * typically represent a generic types for the actual type. For
      * contacts that use a <code>Map</code> type this will be the 
      * generic type parameter for that map type declaration.
      * 
      * @return this returns the dependent type for the contact
      */
     public Class[] getDependents() {
        return items;
     } 
     
     /**
      * This is the class that declares the contact. The declaring
      * class is where the method represented has been defined. This 
      * will typically be a class rather than an interface.
      * 
      * @return this returns the class the contact is declared within
      */
     public Class getDeclaringClass() {
        return owner;
     }
     
     /**
      * This is used to acquire the name of the method. This returns
      * the name of the method without the get, set or is prefix that
      * represents the Java Bean method type. Also this decapitalizes
      * the resulting name. The result is used to represent the XML
      * attribute of element within the class schema represented.
      * 
      *  @return this returns the name of the method represented
      */
     public String getName() {
        return name;
     }   
  
     /**
      * This is used to set the specified value on the provided object.
      * The value provided must be an instance of the contact class so
      * that it can be set without a runtime class compatibility error.
      *
      * @param source this is the object to set the value on
      * @param value this is the value that is to be set on the object
      */    
     public void set(Object source, Object value) throws Exception{
        Method method = get.getMethod();
        Class type = method.getDeclaringClass();
        
        if(set == null) {
           throw new MethodException("Property '%s' is read only in %s", name, type);
        }
        set.getMethod().invoke(source, value);
     }
     
     /**
      * This is used to get the specified value on the provided object.
      * The value returned from this method will be an instance of the
      * contact class type. If the returned object is of a different
      * type then the serialization process will fail.
      *
      * @param source this is the object to acquire the value from
      *
      * @return this is the value that is acquired from the object
      */ 
     public Object get(Object source) throws Exception {
        return get.getMethod().invoke(source);
     }
     
     /**
      * This is used to describe the contact as it exists within the
      * owning class. It is used to provide error messages that can
      * be used to debug issues that occur when processing a contact.
      * The string provided contains both the set and get methods.
      * 
      * @return this returns a string representation of the contact
      */
     public String toString() {
        return String.format("method '%s'", name);
     }
  }
  