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Notes on Metaschema-aware parsing API

XML Parsing

Deserializer

The main entry point is DefaultXmlDeserializer.deserialize(Reader). This determines the root class and delegates to the ClassBinding.readItem(PropertyCollector, Object, StartElement, XmlParsingContext) method to parse the contents of the assembly using a SingletonPropertyCollector collector for the instance read.

Assembly or Field Bound Classes

The method AbstractClassBinding.readInternal(Object, Object, StartElement, XmlParsingContext) is the main entry point for bound Assembly or Field classes.

This method will first read the flag properties via a call to Property.read(Object, StartElement, XmlParsingContext). It will then call AbstractClassBinding.readBody(Object, StartElement, XmlParsingContext) which is implemented by the AssemblyClassBinding and FieldClassBinding implementations to handled the model contents.

Assembly (DefaultAssemblyClassBinding)

The main entry points for a bound assembly class are:

  • For a root assembly DefaultAssemblyClassBinding.readRoot(XmlParsingContext). In this case the outer wrapper elements are read and then AbstractClassBinding.readInternal(Object, Object, StartElement, XmlParsingContext) is called to read the contents.
  • For any child assembly AbstractClassBinding.readItem(PropertyCollector, Object, StartElement, XmlParsingContext). Then AbstractClassBinding.readInternal(Object, Object, StartElement, XmlParsingContext) is called to read the contents.

After flags are read by AbstractClassBinding.readInternal(Object, Object, StartElement, XmlParsingContext), the method DefaultAssemblyClassBinding.readBody(Object, StartElement, XmlParsingContext) is called from to parse the model contents.

The assembly model contents are read iteratively through calls to Property.read(Object, StartElement, XmlParsingContext).

Call tree:

  • DefaultAssemblyClassBinding.readRoot(XmlParsingContext)
    • AbstractClassBinding.readInternal(Object, Object, StartElement, XmlParsingContext)
      • DefaultAssemblyClassBinding.readBody(Object, StartElement, XmlParsingContext)
        • Property.read(Object, StartElement, XmlParsingContext)
  • AbstractClassBinding{as DefaultAssemblyClassBinding}.readItem(PropertyCollector, Object, StartElement, XmlParsingContext)
    • AbstractClassBinding{as DefaultAssemblyClassBinding}.readInternal(Object, Object, StartElement, XmlParsingContext)
      • DefaultAssemblyClassBinding.readBody(Object, StartElement, XmlParsingContext)
        • Property.read(Object, StartElement, XmlParsingContext)

Field (DefaultFieldClassBinding)

The main entry point for any bound field class is AbstractClassBinding.readItem(PropertyCollector, Object, StartElement, XmlParsingContext). Then AbstractClassBinding.readInternal(Object, Object, StartElement, XmlParsingContext) is called to read the contents.

The field value is read by calling Property.read(Object, StartElement, XmlParsingContext).

Field Value Property (DefaultFieldValueProperty)

The main entry point for a field value is DefaultFieldValueProperty.read(Object, StartElement, XmlParsingContext), which delegates to the type adapter to read the value using JavaTypeAdapter.parse(XMLEventReader2).

Call tree:

- DefaultFieldValueProperty.read(Object, StartElement, XmlParsingContext)
  - JavaTypeAdapter.parse(XMLEventReader2)

Flag Property (DefaultFlagProperty)

The main entry point for a flag value is DefaultFlagProperty.read(Object, StartElement, XmlParsingContext), which delegates to the type adapter to read the value using JavaTypeAdapter.parse(String), since the attribute value is already parsed as a string value.

Call tree:

- DefaultFlagProperty.read(Object, StartElement, XmlParsingContext)
  - JavaTypeAdapter.parse(String)

Assembly Instance Property (DefaultAssemblyProperty)

The main entry point for an assembly instance value is AbstractNamedModelProperty.read(Object, StartElement, XmlParsingContext). This method parses the grouping element if specified by the model. The parsing of the value(s) is delegated to the ModelPropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext) method, which is specific to the occurrence model of the property (i.e., SingletonPropertyInfo, ListPropertyInfo, MapPropertyInfo). A call to PropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext) then delegates to the DefaultAssemblyProperty.readItem(PropertyCollector, Object, StartElement, XmlParsingContext) to read each value item.

The DefaultAssemblyProperty.readItem(PropertyCollector, Object, StartElement, XmlParsingContext) calls AbstractNamedModelProperty.getBindingSupplier() to retrieve the XML value parser (XmlBindingSupplier). Parsing is then delegated to XmlBindingSupplier.get(PropertyCollector, Object, StartElement, XmlParsingContext).

Call tree:

- AbstractNamedModelProperty{as DefaultAssemblyProperty}.read(Object, StartElement, XmlParsingContext)
  - ModelPropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext)
    - PropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext)
      - NamedModelProperty{as DefaultAssemblyProperty}.readItem(PropertyCollector, Object, StartElement, XmlParsingContext)
        - AbstractNamedModelProperty{as DefaultAssemblyProperty}.getBindingSupplier()
          - XmlBindingSupplier.get(PropertyCollector, Object, StartElement, XmlParsingContext)

Field Instance Property (DefaultFieldProperty)

The main entry point for a field instance value is AbstractNamedModelProperty.read(Object, StartElement, XmlParsingContext). This method parses the grouping element if specified by the model. The parsing of the value(s) is delegated to the ModelPropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext) method, which is specific to the occurrence model of the property (i.e., SingletonPropertyInfo, ListPropertyInfo, MapPropertyInfo). A call to PropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext) then delegates to the DefaultFieldProperty.readItem(PropertyCollector, Object, StartElement, XmlParsingContext) to read each value item.

The DefaultAssemblyProperty.readItem(PropertyCollector, Object, StartElement, XmlParsingContext) calls AbstractNamedModelProperty.getBindingSupplier() to retrieve the XML value parser (XmlBindingSupplier). Parsing is then delegated to XmlBindingSupplier.get(PropertyCollector, Object, StartElement, XmlParsingContext).

Call tree:

- AbstractNamedModelProperty{as DefaultFieldProperty}.read(Object, StartElement, XmlParsingContext)
  - ModelPropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext)
    - PropertyInfo.readValue(PropertyCollector, Object, StartElement, XmlParsingContext)
      - NamedModelProperty{as DefaultFieldProperty}.readItem(PropertyCollector, Object, StartElement, XmlParsingContext)
        - AbstractNamedModelProperty{as DefaultFieldProperty}.getBindingSupplier()
          - XmlBindingSupplier.get(PropertyCollector, Object, StartElement, XmlParsingContext)

XML instance value parsing (XmlBindingSupplier)

The XML value parser delegates value parsing by calling XmlBindingSupplier.get(PropertyCollector, Object, StartElement, XmlParsingContext).

There are two types of binding suppliers:

  • For bound classes, ClassDataTypeHandler delegates parsing to a bound field (DefaultFieldClassBinding) or assembly (DefaultAssemblyClassBinding) class by calling the AbstractClassBinding.readItem(PropertyCollector, Object, StartElement, XmlParsingContext) method.
  • For scalar values, JavaTypeAdapterDataTypeHandler delegates to the type adapter to read the value using the JavaTypeAdapter.parse(XMLEventReader2) method.

Call tree:

- XmlBindingSupplier{as ClassDataTypeHandler}.get(PropertyCollector, Object, StartElement, XmlParsingContext)
  - AbstractClassBinding(as DefaultFieldClassBinding or DefaultAssemblyClassBinding}.readItem(PropertyCollector, Object, StartElement, XmlParsingContext)
- XmlBindingSupplier{as JavaTypeAdapterDataTypeHandler}.get(PropertyCollector, Object, StartElement, XmlParsingContext)
  - JavaTypeAdapter.parse(XMLEventReader2)