content: /*
   * ModelSection.java November 2010
   *
   * Copyright (C) 2010, 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.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * The <code>ModelSection</code> represents a section that is backed
   * by a <code>Model</code> instance. This is used to expose the XML
   * structure of a schema class. In addition to wrapping the model
   * this will also apply a <code>Style</code> to the names of the
   * attributes and elements of the class schema. 
   * 
   * @author Niall Gallagher
   */
  class ModelSection implements Section { 
  
     /**
      * Represents a mapping between styled names and attributes.
      */
     private LabelMap attributes;
     
     /**
      * Represents a mapping between styled names and elements.
      */
     private LabelMap elements;
     
     /**
      * Represents a mapping between styled names and models.
      */
     private ModelMap models;
     
     /**
      * This is the model that contains the elements and attributes.
      */
     private Model model;
     
     /**
      * Constructor for the <code>ModelSection</code> object. This is
      * used to wrap a <code>Model</code> in such a way that it can
      * not be modified. This allows it to be used concurrently.
      * 
      * @param model this is the model this section will wrap
      */
     public ModelSection(Model model) {
        this.model = model;
     }
     
     /**
      * This is used to return the name of the section. The name is 
      * must be a valid XML element name. It is used when a style
      * is applied to a path as the section name must be styled.
      * 
      * @return this returns the name of this section instance
      */
     public String getName() {
        return model.getName();
     }
     
     /**
      * This is used to acquire the path prefix for the section. The
      * path prefix is used when the section is transformed in to an
      * XML structure. This ensures that the XML element created to
      * represent the section contains the optional prefix.
      * 
      * @return this returns the prefix for this section
      */
     public String getPrefix() {
        return model.getPrefix();
     }
     
     /**
      * This is used to acquire the full element path for this
      * section. The element path is simply the fully qualified
      * path for this expression with the provided name appended.
      * If this is an empty path, the provided name is returned.
      * 
      * @param name this is the name of the element to be used
      * 
      * @return a fully qualified path for the specified name
      */
     public String getPath(String name) throws Exception {
        Expression path = model.getExpression();
        
        if(path == null) {
           return name;
        }
        return path.getElement(name);
     }
     
     /**
      * This is used to acquire the full attribute path for this 
      * section. The attribute path is simply the fully qualified
      * path for this expression with the provided name appended.
      * If this is an empty path, the provided name is returned.
      * 
      * @param name this is the name of the attribute to be used
      * 
      * @return a fully qualified path for the specified name
      */
     public String getAttribute(String name) throws Exception {
        Expression path = model.getExpression();
        
        if(path == null) {
           return name;
        }
        return path.getAttribute(name);
     }
     
     /**
      * This will return the names of all elements contained within
      * the model. This includes the names of all XML elements that
      * have been registered as well as any other models that have
      * been added. Iteration is done in an ordered manner, according
      * to the registration of elements and models.
      * 
      * @return an ordered and styled list of elements and models
      */
     public Iterator<String> iterator() {
        List<String> list = new ArrayList<String>();
        
        for(String element : model) {
           list.add(element);
        }
        return list.iterator();
     }
     
     /**
      * To differentiate between a section and an element this can be
      * used. When iterating over the elements within the section the
      * names of both elements and sections are provided. So in order
      * to determine how to interpret the structure this can be used.
      * 
      * @param name this is the name of the element to be determined
      * 
      * @return this returns true if the name represents a section
      */   
     public boolean isSection(String name) throws Exception {      
        return getModels().get(name) != null;
     }
     
     /**
      * Returns a <code>LabelMap</code> that contains the details for
      * all fields and methods marked with XML annotations. All of the
      * attribute annotations are considered and gathered by name in 
      * this map. Also, if there is an associated <code>Style</code> 
      * for serialization the attribute names are renamed with this.
      * 
      * @return returns the attributes associated with this section
      */
     public ModelMap getModels() throws Exception {
        if(models == null) {
           models = model.getModels();
        }
        return models;
     }
  
     /**
      * This is used to acquire the text label for this section if 
      * one has been specified. A text label can only exist in a
      * section if there are no elements associated with the section
      * and the section is not composite, as in it does not contain
      * any further sections.
      * 
      * @return this returns the text label for this section
      */
     public Label getText() throws Exception {
        return model.getText();
     }
  
     /**
      * Returns a <code>LabelMap</code> that contains the details for
      * all fields and methods marked with XML annotations. All of the
      * attribute annotations are considered and gathered by name in 
      * this map. Also, if there is an associated <code>Style</code> 
      * for serialization the attribute names are renamed with this.
      * 
      * @return returns the attributes associated with this section
      */
     public LabelMap getAttributes() throws Exception {
        if(attributes == null) {
           attributes = model.getAttributes();
        }
        return attributes;
     }
  
     /**
      * Returns a <code>LabelMap</code> that contains the details for
      * all fields and methods marked with XML annotations. All of the
      * element annotations are considered and gathered by name in 
      * this map. Also, if there is an associated <code>Style</code> 
      * for serialization the element names are renamed with this.
      * 
      * @return returns the elements associated with this section
      */
     public LabelMap getElements() throws Exception {
        if(elements == null) {
           elements = model.getElements();
        }
        return elements;
     }
     
     /**
      * Returns the named element as a <code>Label</code> object.
      * For convenience this method is provided so that when iterating
      * over the names of the elements in the section a specific one
      * of interest can be acquired. 
      * <p>
      * To ensure that elements of the same name are not referenced
      * more than once this will remove the element once acquired. 
      * This ensures that they are visited only once in serialization.
      * 
      * @param name the name of the element that is to be acquired
      * 
      * @return this returns the label associated with the name
      */
     public Label getElement(String name) throws Exception {
        return getElements().getLabel(name);
     }
  
     /**
      * Returns the named section as a <code>Section</code> object.
      * For convenience this method is provided so that when iterating
      * over the names of the elements in the section a specific one
      * of interest can be acquired. 
      * <p>
      * To ensure that models of the same name are not referenced
      * more than once this will remove the model once acquired. 
      * This ensures that they are visited only once in serialization.
      * 
      * @param name the name of the element that is to be acquired
      * 
      * @return this returns the section associated with the name
      */
     public Section getSection(String name) throws Exception {
        ModelMap map = getModels();
        ModelList list = map.get(name);      
        
        if(list != null) {
           Model model = list.take();
           
           if(model != null){
              return new ModelSection(model);
           }
        }
        return null;
     }
  }
  