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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau;

import static org.apache.juneau.internal.StringUtils.*;

import java.io.*;
import java.util.*;

import org.apache.juneau.annotation.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.json.*;
import org.apache.juneau.parser.*;
import org.apache.juneau.reflect.*;
import org.apache.juneau.transform.*;
import org.apache.juneau.xml.annotation.*;

/**
 * Java bean wrapper class.
 *
 * <h5 class='topic'>Description</h5>
 *
 * A wrapper that wraps Java bean instances inside of a {@link Map} interface that allows properties on the wrapped
 * object can be accessed using the {@link Map#get(Object) get()} and {@link Map#put(Object,Object) put()} methods.
 *
 * <p>
 * Use the {@link BeanContext} class to create instances of this class.
 *
 * <h5 class='topic'>Bean property order</h5>
 *
 * The order of the properties returned by the {@link Map#keySet() keySet()} and {@link Map#entrySet() entrySet()}
 * methods are as follows:
 * <ul class='spaced-list'>
 *    <li>
 *       If {@link Bean @Bean} annotation is specified on class, then the order is the same as the list of properties
 *       in the annotation.
 *    <li>
 *       If {@link Bean @Bean} annotation is not specified on the class, then the order is the same as that returned
 *       by the {@link java.beans.BeanInfo} class (i.e. ordered by definition in the class).
 * </ul>
 *
 * <p>
 * <br>The order can also be overridden through the use of a {@link BeanFilter}.
 *
 * <h5 class='topic'>POJO swaps</h5>
 *
 * If {@link PojoSwap PojoSwaps} are defined on the class types of the properties of this bean or the bean properties
 * themselves, the {@link #get(Object)} and {@link #put(String, Object)} methods will automatically transform the
 * property value to and from the serialized form.
 *
 * @param <T> Specifies the type of object that this map encapsulates.
 */
public class BeanMap<T> extends AbstractMap<String,Object> implements Delegate<T> {

   /** The wrapped object. */
   protected T bean;

   /** Temporary holding cache for beans with read-only properties.  Normally null. */
   protected Map<String,Object> propertyCache;

   /** Temporary holding cache for bean properties of array types when the add() method is being used. */
   protected Map<String,List<?>> arrayPropertyCache;

   /** The BeanMeta associated with the class of the object. */
   protected BeanMeta<T> meta;

   private final BeanSession session;
   private final String typePropertyName;

   /**
    * Convenience method for wrapping a bean inside a {@link BeanMap}.
    *
    * @param <T> The bean type.
    * @param bean The bean being wrapped.
    * @return A new {@link BeanMap} instance wrapping the bean.
    */
   public static <T> BeanMap<T> create(T bean) {
      return BeanContext.DEFAULT.createBeanSession().toBeanMap(bean);
   }

   /**
    * Instance of this class are instantiated through the BeanContext class.
    *
    * @param session The bean session object that created this bean map.
    * @param bean The bean to wrap inside this map.
    * @param meta The metadata associated with the bean class.
    */
   protected BeanMap(BeanSession session, T bean, BeanMeta<T> meta) {
      this.session = session;
      this.bean = bean;
      this.meta = meta;
      if (meta.constructorArgs.length > 0)
         propertyCache = new TreeMap<>();
      this.typePropertyName = session.getBeanTypePropertyName(meta.classMeta);
   }

   /**
    * Returns the metadata associated with this bean map.
    *
    * @return The metadata associated with this bean map.
    */
   public BeanMeta<T> getMeta() {
      return meta;
   }

   /**
    * Returns the bean session that created this bean map.
    *
    * @return The bean session that created this bean map.
    */
   public final BeanSession getBeanSession() {
      return session;
   }

   /**
    * Returns the wrapped bean object.
    *
    * <p>
    * Triggers bean creation if bean has read-only properties set through a constructor defined by the
    * {@link Beanc @Beanc} annotation.
    *
    * @return The inner bean object.
    */
   public T getBean() {
      T b = getBean(true);

      // If we have any arrays that need to be constructed, do it now.
      if (arrayPropertyCache != null) {
         for (Map.Entry<String,List<?>> e : arrayPropertyCache.entrySet()) {
            String key = e.getKey();
            List<?> value = e.getValue();
            BeanPropertyMeta bpm = getPropertyMeta(key);
            try {
               bpm.setArray(b, value);
            } catch (Exception e1) {
               throw new RuntimeException(e1);
            }
         }
         arrayPropertyCache = null;
      }

      // Initialize any null Optional<X> fields.
      for (BeanPropertyMeta pMeta : this.meta.properties.values()) {
         ClassMeta<?> cm = pMeta.getClassMeta();
         if (cm.isOptional() && pMeta.get(this, pMeta.getName()) == null)
            pMeta.set(this, pMeta.getName(), cm.getOptionalDefault());
      }
      // Do the same for hidden fields.
      for (BeanPropertyMeta pMeta : this.meta.hiddenProperties.values()) {
         ClassMeta<?> cm = pMeta.getClassMeta();
         if (cm.isOptional() && pMeta.get(this, pMeta.getName()) == null)
            pMeta.set(this, pMeta.getName(), cm.getOptionalDefault());
      }

      return b;
   }

   /**
    * Returns the wrapped bean object.
    *
    * <p>
    * If <c>create</c> is <jk>false</jk>, then this method may return <jk>null</jk> if the bean has read-only
    * properties set through a constructor defined by the {@link Beanc @Beanc} annotation.
    *
    * <p>
    * This method does NOT always return the bean in it's final state.
    * Array properties temporary stored as ArrayLists are not finalized until the {@link #getBean()} method is called.
    *
    * @param create If bean hasn't been instantiated yet, then instantiate it.
    * @return The inner bean object.
    */
   public T getBean(boolean create) {
      /** If this is a read-only bean, then we need to create it. */
      if (bean == null && create && meta.constructorArgs.length > 0) {
         String[] props = meta.constructorArgs;
         ConstructorInfo c = meta.constructor;
         Object[] args = new Object[props.length];
         for (int i = 0; i < props.length; i++)
            args[i] = propertyCache.remove(props[i]);
         try {
            bean = c.<T>invoke(args);
            for (Map.Entry<String,Object> e : propertyCache.entrySet())
               put(e.getKey(), e.getValue());
            propertyCache = null;
         } catch (IllegalArgumentException e) {
            throw new BeanRuntimeException(e, meta.classMeta.innerClass, "IllegalArgumentException occurred on call to class constructor ''{0}'' with argument types ''{1}''", c.getSimpleName(), SimpleJsonSerializer.DEFAULT.toString(ClassUtils.getClasses(args)));
         } catch (Exception e) {
            throw new BeanRuntimeException(e);
         }
      }
      return bean;
   }

   /**
    * Sets a property on the bean.
    *
    * <p>
    * If there is a {@link PojoSwap} associated with this bean property or bean property type class, then you must pass
    * in a transformed value.
    * For example, if the bean property type class is a {@link Date} and the bean property has the
    * {@link org.apache.juneau.transforms.TemporalDateSwap.IsoInstant} swap associated with it through the
    * {@link Swap#value() @Swap(value)} annotation, the value being passed in must be
    * a String containing an ISO8601 date-time string value.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a bean with a 'birthDate' Date field</jc>
    *    Person p = <jk>new</jk> Person();
    *
    *    <jc>// Create a bean context and add the ISO8601 date-time swap</jc>
    *    BeanContext beanContext = <jk>new</jk> BeanContext().swaps(DateSwap.ISO8601DT.<jk>class</jk>);
    *
    *    <jc>// Wrap our bean in a bean map</jc>
    *    BeanMap&lt;Person&gt; b = beanContext.forBean(p);
    *
    *    <jc>// Set the field</jc>
    *    myBeanMap.put(<js>"birthDate"</js>, <js>"'1901-03-03T04:05:06-5000'"</js>);
    * </p>
    *
    * @param property The name of the property to set.
    * @param value The value to set the property to.
    * @return
    *    If the bean context setting {@code beanMapPutReturnsOldValue} is <jk>true</jk>, then the old value of the
    *    property is returned.
    *    Otherwise, this method always returns <jk>null</jk>.
    * @throws
    *    RuntimeException if any of the following occur.
    *    <ul>
    *       <li>BeanMapEntry does not exist on the underlying object.
    *       <li>Security settings prevent access to the underlying object setter method.
    *       <li>An exception occurred inside the setter method.
    *    </ul>
    */
   @Override /* Map */
   public Object put(String property, Object value) {
      BeanPropertyMeta p = getPropertyMeta(property);
      if (p == null) {
         if (meta.ctx.isIgnoreUnknownBeanProperties())
            return meta.onWriteProperty(bean, property, null);

         if (property.equals(typePropertyName))
            return meta.onWriteProperty(bean, property, null);

         p = getPropertyMeta("*");
         if (p == null)
            throw new BeanRuntimeException(meta.c, "Bean property ''{0}'' not found.", property);
      }
      return p.set(this, property, value);
   }

   @Override /* Map */
   public boolean containsKey(Object property) {
      if (getPropertyMeta(emptyIfNull(property)) != null)
         return true;
      return super.containsKey(property);
   }

   /**
    * Add a value to a collection or array property.
    *
    * <p>
    * As a general rule, adding to arrays is not recommended since the array must be recreate each time this method is
    * called.
    *
    * @param property Property name or child-element name (if {@link Xml#childName() @Xml(childName)} is specified).
    * @param value The value to add to the collection or array.
    */
   public void add(String property, Object value) {
      BeanPropertyMeta p = getPropertyMeta(property);
      if (p == null) {
         if (meta.ctx.isIgnoreUnknownBeanProperties())
            return;
         throw new BeanRuntimeException(meta.c, "Bean property ''{0}'' not found.", property);
      }
      p.add(this, property, value);
   }

   /**
    * Gets a property on the bean.
    *
    * <p>
    * If there is a {@link PojoSwap} associated with this bean property or bean property type class, then this method
    * will return the transformed value.
    * For example, if the bean property type class is a {@link Date} and the bean property has the
    * {@link org.apache.juneau.transforms.TemporalDateSwap.IsoInstant} swap associated with it through the
    * {@link Swap#value() @Swap(value)} annotation, this method will return a String containing an
    * ISO8601 date-time string value.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a bean with a 'birthDate' Date field</jc>
    *    Person p = <jk>new</jk> Person();
    *    p.setBirthDate(<jk>new</jk> Date(1, 2, 3, 4, 5, 6));
    *
    *    <jc>// Create a bean context and add the ISO8601 date-time swap</jc>
    *    BeanContext beanContext = <jk>new</jk> BeanContext().swaps(DateSwap.ISO8601DT.<jk>class</jk>);
    *
    *    <jc>// Wrap our bean in a bean map</jc>
    *    BeanMap&lt;Person&gt; b = beanContext.forBean(p);
    *
    *    <jc>// Get the field as a string (i.e. "'1901-03-03T04:05:06-5000'")</jc>
    *    String s = myBeanMap.get(<js>"birthDate"</js>);
    * </p>
    *
    * @param property The name of the property to get.
    * @throws
    *    RuntimeException if any of the following occur.
    *    <ol>
    *       <li>BeanMapEntry does not exist on the underlying object.
    *       <li>Security settings prevent access to the underlying object getter method.
    *       <li>An exception occurred inside the getter method.
    *    </ol>
    */
   @Override /* Map */
   public Object get(Object property) {
      String pName = stringify(property);
      BeanPropertyMeta p = getPropertyMeta(pName);
      if (p == null) 
         return meta.onReadProperty(this.bean, pName, null);
      return p.get(this, pName);
   }

   /**
    * Same as {@link #get(Object)} except bypasses the POJO filter associated with the bean property or bean filter
    * associated with the bean class.
    *
    * @param property The name of the property to get.
    * @return The raw property value.
    */
   public Object getRaw(Object property) {
      String pName = stringify(property);
      BeanPropertyMeta p = getPropertyMeta(pName);
      if (p == null)
         return null;
      return p.getRaw(this, pName);
   }

   /**
    * Convenience method for setting multiple property values by passing in JSON text.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    aPersonBean.load(<js>"{name:'John Smith',age:21}"</js>)
    * </p>
    *
    * @param input The text that will get parsed into a map and then added to this map.
    * @return This object (for method chaining).
    * @throws ParseException Malformed input encountered.
    */
   public BeanMap<T> load(String input) throws ParseException {
      putAll(OMap.ofJson(input));
      return this;
   }

   /**
    * Convenience method for setting multiple property values by passing in a reader.
    *
    * @param r The text that will get parsed into a map and then added to this map.
    * @param p The parser to use to parse the text.
    * @return This object (for method chaining).
    * @throws ParseException Malformed input encountered.
    * @throws IOException Thrown by <c>Reader</c>.
    */
   public BeanMap<T> load(Reader r, ReaderParser p) throws ParseException, IOException {
      putAll(OMap.ofText(r, p));
      return this;
   }

   /**
    * Convenience method for loading this map with the contents of the specified map.
    *
    * <p>
    * Identical to {@link #putAll(Map)} except as a fluent-style method.
    *
    * @param entries The map containing the entries to add to this map.
    * @return This object (for method chaining).
    */
   @SuppressWarnings({"unchecked","rawtypes"})
   public BeanMap<T> load(Map entries) {
      putAll(entries);
      return this;
   }

   /**
    * Returns the names of all properties associated with the bean.
    *
    * <p>
    * The returned set is unmodifiable.
    */
   @Override /* Map */
   public Set<String> keySet() {
      if (meta.dynaProperty == null)
         return meta.properties.keySet();
      Set<String> l = new LinkedHashSet<>();
      for (String p : meta.properties.keySet())
         if (! "*".equals(p))
            l.add(p);
      try {
         l.addAll(meta.dynaProperty.getDynaMap(bean).keySet());
      } catch (Exception e) {
         throw new BeanRuntimeException(e);
      }
      return l;
   }

   /**
    * Returns the specified property on this bean map.
    *
    * <p>
    * Allows you to get and set an individual property on a bean without having a handle to the bean itself by using
    * the {@link BeanMapEntry#getValue()} and {@link BeanMapEntry#setValue(Object)} methods.
    *
    * <p>
    * This method can also be used to get metadata on a property by calling the {@link BeanMapEntry#getMeta()} method.
    *
    * @param propertyName The name of the property to look up.
    * @return The bean property, or null if the bean has no such property.
    */
   public BeanMapEntry getProperty(String propertyName) {
      BeanPropertyMeta p = getPropertyMeta(propertyName);
      if (p == null)
         return null;
      return new BeanMapEntry(this, p, propertyName);
   }

   /**
    * Returns the metadata on the specified property.
    *
    * @param propertyName The name of the bean property.
    * @return Metadata on the specified property, or <jk>null</jk> if that property does not exist.
    */
   public BeanPropertyMeta getPropertyMeta(String propertyName) {
      return meta.getPropertyMeta(propertyName);
   }

   /**
    * Returns the {@link ClassMeta} of the wrapped bean.
    *
    * @return The class type of the wrapped bean.
    */
   @Override /* Delegate */
   public ClassMeta<T> getClassMeta() {
      return this.meta.getClassMeta();
   }

   /**
    * Invokes all the getters on this bean and return the values as a list of {@link BeanPropertyValue} objects.
    *
    * <p>
    * This allows a snapshot of all values to be grabbed from a bean in one call.
    *
    * @param keepNulls
    *    Also return properties whose values are null.
    * @param prependVals
    *    Additional bean property values to prepended to this list.
    *    Any <jk>null</jk> values in this list will be ignored.
    * @return The list of all bean property values.
    */
   public List<BeanPropertyValue> getValues(boolean keepNulls, BeanPropertyValue...prependVals) {
      Collection<BeanPropertyMeta> properties = getProperties();
      int capacity = ((! keepNulls) && properties.size() > 10) ? 10 : properties.size() + prependVals.length;
      List<BeanPropertyValue> l = new ArrayList<>(capacity);
      for (BeanPropertyValue v : prependVals)
         if (v != null)
            l.add(v);
      for (BeanPropertyMeta bpm : properties) {
         if (bpm.canRead()) {
            try {
               if (bpm.isDyna()) {
                  Map<String,Object> dynaMap = bpm.getDynaMap(bean);
                  if (dynaMap != null) {
                     for (String pName : bpm.getDynaMap(bean).keySet()) {
                        Object val = bpm.get(this, pName);
                        if (val != null || keepNulls)
                           l.add(new BeanPropertyValue(bpm, pName, val, null));
                     }
                  }
               } else {
                  Object val = bpm.get(this, null);
                  if (val != null || keepNulls)
                     l.add(new BeanPropertyValue(bpm, bpm.getName(), val, null));
               }
            } catch (Error e) {
               // Errors should always be uncaught.
               throw e;
            } catch (Throwable t) {
               l.add(new BeanPropertyValue(bpm, bpm.getName(), null, t));
            }
         }
      }
      if (meta.sortProperties && meta.dynaProperty != null)
         Collections.sort(l);
      return l;
   }

   /**
    * Given a string containing variables of the form <c>"{property}"</c>, replaces those variables with property
    * values in this bean.
    *
    * @param s The string containing variables.
    * @return A new string with variables replaced, or the same string if no variables were found.
    */
   public String resolveVars(String s) {
      return StringUtils.replaceVars(s, this);
   }

   /**
    * Returns a simple collection of properties for this bean map.
    *
    * @return A simple collection of properties for this bean map.
    */
   protected Collection<BeanPropertyMeta> getProperties() {
      return meta.properties.values();
   }

   /**
    * Returns all the properties associated with the bean.
    *
    * @return A new set.
    */
   @Override
   public Set<Entry<String,Object>> entrySet() {

      // If this bean has a dyna-property, then we need to construct the entire set before returning.
      // Otherwise, we can create an iterator without a new data structure.
      if (meta.dynaProperty != null) {
         Set<Entry<String,Object>> s = new LinkedHashSet<>();
         for (BeanPropertyMeta pMeta : getProperties()) {
            if (pMeta.isDyna()) {
               try {
                  for (Map.Entry<String,Object> e : pMeta.getDynaMap(bean).entrySet())
                     s.add(new BeanMapEntry(this, pMeta, e.getKey()));
               } catch (Exception e) {
                  throw new BeanRuntimeException(e);
               }
            } else {
               s.add(new BeanMapEntry(this, pMeta, pMeta.getName()));
            }
         }
         return s;
      }

      // Construct our own anonymous set to implement this function.
      Set<Entry<String,Object>> s = new AbstractSet<Entry<String,Object>>() {

         // Get the list of properties from the meta object.
         // Note that the HashMap.values() method caches results, so this collection
         // will really only be constructed once per bean type since the underlying
         // map never changes.
         final Collection<BeanPropertyMeta> pSet = getProperties();

         @Override /* Set */
         public Iterator<java.util.Map.Entry<String, Object>> iterator() {

            // Construct our own anonymous iterator that uses iterators against the meta.properties
            // map to maintain position.  This prevents us from having to construct any of our own
            // collection objects.
            return new Iterator<Entry<String,Object>>() {

               final Iterator<BeanPropertyMeta> pIterator = pSet.iterator();

               @Override /* Iterator */
               public boolean hasNext() {
                  return pIterator.hasNext();
               }

               @Override /* Iterator */
               public Map.Entry<String, Object> next() {
                  return new BeanMapEntry(BeanMap.this, pIterator.next(), null);
               }

               @Override /* Iterator */
               public void remove() {
                  throw new UnsupportedOperationException("Cannot remove item from iterator.");
               }
            };
         }

         @Override /* Set */
         public int size() {
            return pSet.size();
         }
      };

      return s;
   }

   @SuppressWarnings("unchecked")
   void setBean(Object bean) {
      this.bean = (T)bean;
   }
}