content: /*
   * Collector.java December 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.util.Collection;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  
  /**
   * The <code>Collector</code> object is used to store variables for
   * a deserialized object. Each variable contains the label and value
   * for a field or method. The <code>Composite</code> object uses
   * this to store deserialized values before committing them to the
   * objects methods and fields. 
   * 
   * @author Niall Gallagher
   * 
   * @see Composite
   */
  class Collector implements Criteria {
     
     /**
      * This is the registry containing all the variables collected.
      */
     private final Registry registry;
     
     /**
      * This is the registry that contains variables mapped to paths.
      */
     private final Registry alias;
     
     /**
      * Constructor for the <code>Collector</code> object. This is 
      * used to store variables for an objects fields and methods.
      * Each variable is stored using the name of the label.
      */
     public Collector() {
        this.registry = new Registry();
        this.alias = new Registry();
     }
  
     /**
      * This is used to get the <code>Variable</code> that represents
      * a deserialized object. The variable contains all the meta
      * data for the field or method and the value that is to be set
      * on the method or field.
      * 
      * @param key this is the key of the variable to be acquired
      * 
      * @return this returns the keyed variable if it exists
      */
     public Variable get(Object key) {
        return registry.get(key);
     } 
     
     /**
      * This is used to get the <code>Variable</code> that represents
      * a deserialized object. The variable contains all the meta
      * data for the field or method and the value that is to be set
      * on the method or field.
      * 
      * @param label this is the label to resolve the variable with
      * 
      * @return this returns the variable associated with the label
      */
     public Variable get(Label label) throws Exception {
        if(label != null) {
           Object key = label.getKey();
           
           return registry.get(key);
        }
        return null;
     } 
     
     /**
      * This is used to resolve the <code>Variable</code> by using 
      * the union names of a label. This will also acquire variables
      * based on the actual name of the variable.
      * 
      * @param path this is the path of the variable to be acquired
      * 
      * @return this returns the variable mapped to the path
      */
     public Variable resolve(String path) {
        return alias.get(path);
     }
     
     /**
      * This is used to remove the <code>Variable</code> from this
      * criteria object. When removed, the variable will no longer be
      * used to set the method or field when the <code>commit</code>
      * method is invoked.
      * 
      * @param key this is the key associated with the variable
      * 
      * @return this returns the keyed variable if it exists
      */
     public Variable remove(Object key) throws Exception{
        return registry.remove(key);
     }
     
     /**
      * This is used to acquire an iterator over the named variables.
      * Providing an <code>Iterator</code> allows the criteria to be
      * used in a for each loop. This is primarily for convenience.
      * 
      * @return this returns an iterator of all the variable names
      */
     public Iterator<Object> iterator() {
        return registry.iterator();
     }
     
     /**
      * This is used to create a <code>Variable</code> and set it for
      * this criteria. The variable can be retrieved at a later stage
      * using the name of the label. This allows for repeat reads as
      * the variable can be used to acquire the labels converter.
      * 
      * @param label this is the label used to create the variable
      * @param value this is the value of the object to be read
      */
     public void set(Label label, Object value) throws Exception {
        Variable variable = new Variable(label, value);
  
        if(label != null) {
           String[] paths = label.getPaths();
           Object key = label.getKey();
           
           for(String path : paths) {
              alias.put(path,  variable);
           }
           registry.put(key, variable);
        }
     }
     
     /**
      * This is used to set the values for the methods and fields of
      * the specified object. Invoking this performs the population
      * of an object being deserialized. It ensures that each value 
      * is set after the XML element has been fully read.
      * 
      * @param source this is the object that is to be populated
      */
     public void commit(Object source) throws Exception {
        Collection<Variable> set = registry.values();
        
        for(Variable entry : set) { 
           Contact contact = entry.getContact();
           Object value = entry.getValue();
  
           contact.set(source, value);
        }
     }  
     
     /**
      * The <code>Registry</code> object is used to store variables 
      * for the collector. All variables are stored under its name so
      * that they can be later retrieved and used to populate the
      * object when deserialization of all variables has finished.
      * 
      * @author Niall Gallagher
      */
     private static class Registry extends LinkedHashMap<Object, Variable> {
        
        /**
         * This is used to iterate over the names of the variables
         * in the registry. This is primarily used for convenience
         * so that the variables can be acquired in a for each loop.
         * 
         * @return an iterator containing the names of the variables
         */
        public Iterator<Object> iterator() {
           return keySet().iterator();
        }
     }
  }