content: /*
   * CacheParameter.java April 2012
   *
   * Copyright (C) 2012, 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;
  
  /**
   * The <code>CacheParameter</code> object represents a parameter 
   * which caches its values internally. As well as caching parameter
   * values this also caches a key from a <code>Label</code> object
   * which ties the parameter an label together making it possible
   * to reference each other from hash containers.
   * 
   * @author Niall Gallagher
   */
  class CacheParameter implements Parameter{
  
     /**
      * This is the annotation used to represent this parameter.
      */
     private final Annotation annotation;
     
     /**
      * This is the XPath expression used to represent the parameter.
      */
     private final Expression expression;
     
     /**
      * This is the name of the element or attribute for the parameter.
      */
     private final String name;
     
     /**
      * This is the path of the element or attribute for the parameter.
      */
     private final String path;
     
     /**
      * This is the string representation of this parameter object.
      */
     private final String string;
     
     /**
      * This is the type within the constructor of this parameter.
      */
     private final Class type;
     
     /**
      * This is the key that uniquely identifies this parameter.
      */
     private final Object key;
     
     /**
      * This is the index within the constructor for the parameter.
      */
     private final int index;
     
     /**
      * Determines if this parameter represents a primitive value.
      */
     private final boolean primitive;
     
     /**
      * This is true if this parameter is required to exist.
      */
     private final boolean required;
     
     /**
      * This is true if this parameter represents an attribute.
      */
     private final boolean attribute;
     
     /**
      * This is true if this parameter represents a text value.
      */
     private final boolean text;
     
     /**
      * Constructor for the <code>CacheParameter</code> object. This
      * is used to create a parameter that internally caches all of
      * the information of the provided parameter and also makes 
      * use of the label provided to generate a unique key.
      * 
      * @param value this is the parameter to cache values from
      * @param label this is the label to acquire the key from
      */
     public CacheParameter(Parameter value, Label label) throws Exception {
        this.annotation = value.getAnnotation();
        this.expression = value.getExpression();
        this.attribute = value.isAttribute();
        this.primitive = value.isPrimitive();
        this.required = label.isRequired();
        this.string = value.toString();
        this.text = value.isText();
        this.index = value.getIndex();
        this.name = value.getName();
        this.path = value.getPath();
        this.type = value.getType();
        this.key = label.getKey();
     }
     
     /**
      * This is the key used to represent the parameter. The key is
      * used to store the parameter in hash containers. Unlike the
      * path is not necessarily the path for the parameter.
      * 
      * @return this is the key used to represent the parameter
      */
     public Object getKey() {
        return key;
     }
  
     /**
      * This is used to acquire the annotated type class. The class
      * is the type that is to be deserialized from the XML. This
      * is used to validate against annotated fields and methods.
      * 
      * @return this returns the type used for the parameter
      */
     public Class getType() {
        return type;
     }
  
     /**
      * This returns the index position of the parameter in the
      * constructor. This is used to determine the order of values
      * that are to be injected in to the constructor.
      * 
      * @return this returns the index for the parameter
      */
     public int getIndex() {
        return index;
     }
  
     /**
      * This is used to acquire the annotation that is used for the
      * parameter. The annotation provided will be an XML annotation
      * such as the <code>Element</code> or <code>Attribute</code>
      * annotation.
      * 
      * @return this returns the annotation used on the parameter
      */
     public Annotation getAnnotation() {
        return annotation;
     }
  
     /**
      * This method is used to return an XPath expression that is 
      * used to represent the position of this parameter. If there is 
      * no XPath expression associated with this then an empty path 
      * is returned. This will never return a null expression.
      * 
      * @return the XPath expression identifying the location
      */
     public Expression getExpression() {
        return expression;
     }
  
     /**
      * This is used to acquire the name of the parameter that this
      * represents. The name is determined using annotation and 
      * the name attribute of that annotation, if one is provided.
      * 
      * @return this returns the name of the annotated parameter
      */
     public String getName() {
        return name;
     }
  
     /**
      * This is used to acquire the path of the element or attribute
      * represented by this parameter. The path is determined by
      * acquiring the XPath expression and appending the name of the
      * label to form a fully qualified path.
      * 
      * @return returns the path that is used for this parameter
      */
     public String getPath() {
        return path;
     }
  
     /**
      * This is used to determine if the parameter is required. If 
      * an attribute is not required then it can be null. Which 
      * means that we can inject a null value. Also, this means we
      * can match constructors in a more flexible manner.
      * 
      * @return this returns true if the parameter is required
      */
     public boolean isRequired() {
        return required;
     }
  
     /**
      * This is used to determine if the parameter is primitive. A
      * primitive parameter must not be null. As there is no way to
      * provide the value to the constructor. A default value is 
      * not a good solution as it affects the constructor score.
      * 
      * @return this returns true if the parameter is primitive
      */
     public boolean isPrimitive() {
        return primitive;
     }
  
     /**
      * This method is used to determine if the parameter represents 
      * an attribute. This is used to style the name so that elements
      * are styled as elements and attributes are styled as required.
      * 
      * @return this is used to determine if this is an attribute
      */
     public boolean isAttribute() {
        return attribute;
     }
  
     /**
      * This is used to determine if the parameter represents text. 
      * If this represents text it typically does not have a name,
      * instead the empty string represents the name. Also text
      * parameters can not exist with other text parameters.
      * 
      * @return returns true if this parameter represents text
      */
     public boolean isText() {
        return text;
     }
     
     /**
      * This is used to provide a textual representation of the 
      * parameter. Providing a string describing the parameter is
      * useful for debugging and for exception messages.
      * 
      * @return this returns the string representation for this
      */
     public String toString() {
        return string;
     }  
  }