Module: Jinx::Introspector

Includes:
Propertied
Included in:
Metadata
Defined in:
lib/jinx/metadata/introspector.rb

Overview

Meta-data mix-in to infer attribute meta-data from Java properties.

Instance Attribute Summary

Attributes included from Propertied

#attributes, #defaults

Instance Method Summary collapse

Methods included from Propertied

#add_alternate_key_attribute, #add_attribute, #add_attribute_aliases, #add_attribute_default, #add_attribute_defaults, #add_mandatory_attribute, #add_mandatory_attributes, #add_primary_key_attribute, #add_property, #add_restriction, #add_secondary_key_attribute, #alias_attribute, #alias_standard_attribute_hash, #all_key_attributes, #alternate_key_attributes, #append_ancestor_enum, #attribute_filter, #collect_mandatory_attributes, #collection_attribute?, #create_nonjava_property, #default_mandatory_local_attributes, #dependent_attributes, #detect_attribute_with_type, #domain_attribute?, #domain_attributes, #each_property, #independent_attributes, #init_property_classifiers, #java_attributes, #mandatory_attributes, #mandatory_owner_attribute, #most_specific_domain_attribute, #nondomain_attribute?, #nondomain_attributes, #nondomain_java_attributes, #nonowner_attributes, #offset_attribute, #primary_key_attributes, #property, #property_defined?, #property_hash, #property_path, #qualify_attribute, #register_property_alias, #remove_attribute, #secondary_key_attributes, #secondary_key_non_owner_domain_attributes, #set_alternate_key_attributes, #set_attribute_type, #set_primary_key_attributes, #set_secondary_key_attributes, #standard_attribute, #unidirectional_dependent_attributes

Instance Method Details

#add_attribute_value_initializer ⇒ Object

Adds an optional attribute=>value constructor parameter to this class.



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# File 'lib/jinx/metadata/introspector.rb', line 18

def add_attribute_value_initializer
  class << self
    def new(params=nil)
      obj = super()
      obj.merge_attributes(params) if params
      obj
    end
  end
  logger.debug { "#{self} is extended with an optional {attribute=>value} constructor parameter." }
end

#add_java_property(pd) ⇒ Property (private)

Makes a standard attribute for the given property descriptor. Adds a camelized Java-like alias to the standard attribute.

Parameters:

  • the (Java::PropertyDescriptor) —

    introspected property descriptor

Returns:



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# File 'lib/jinx/metadata/introspector.rb', line 153

def add_java_property(pd)
  # make the attribute metadata
  prop = create_java_property(pd)
  add_property(prop)
  # the property name is an alias for the standard attribute
  pa = prop.attribute
  # the Java property name as an attribute symbol
  ja = pd.name.to_sym
  delegate_to_property(ja, prop) unless prop.reader == ja
  prop
end

#alias_property_accessors(property) ⇒ Object (private)

Aliases the given Ruby property reader and writer to its underlying Java property reader and writer, resp.

Parameters:

  • property (Property) —

    the property to alias



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# File 'lib/jinx/metadata/introspector.rb', line 140

def alias_property_accessors(property)
  # the Java reader and writer accessor method symbols
  jra, jwa = property.java_accessors
  # strip the Java reader and writer is/get/set prefix and make a symbol
  alias_method(property.reader, jra)
  alias_method(property.writer, jwa)
end

#create_java_property(pd) ⇒ Property (private)

Returns the new property.

Parameters:

  • the (Java::PropertyDescriptor) —

    introspected property descriptor

Returns:



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# File 'lib/jinx/metadata/introspector.rb', line 167

def create_java_property(pd)
  JavaProperty.new(pd, self)
end

#define_java_property(pd) ⇒ Object (private)

Defines the Java property attribute and standard attribute methods, e.g. study_protocol and studyProtocol. A boolean attribute is provisioned with an additional reader alias, e.g. available? for is_available.

A standard attribute which differs from the property attribute delegates to the property attribute, e.g. study_protocol delegates to studyProtocol rather than aliasing setStudyProtocol. Redefining these methods results in a call to the redefined method. This contrasts with a Ruby alias, where each attribute alias is bound to the respective attribute reader or writer.

Parameters:

  • the (Java::PropertyDescriptor) —

    introspected property descriptor



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# File 'lib/jinx/metadata/introspector.rb', line 75

def define_java_property(pd)
  if transient?(pd) then
    logger.debug { "Ignoring #{name.demodulize} transient attribute #{pd.name}." }
    return
  end
  # the standard underscore lower-case attributes
  prop = add_java_property(pd)
  # delegate the standard attribute accessors to the attribute accessors
  alias_property_accessors(prop)
  # add special wrappers
  wrap_java_property(prop)
  # create Ruby alias for boolean, e.g. alias :empty? for :empty
  if pd.property_type.name[/\w+$/].downcase == 'boolean' then
    # Strip the leading is_, if any, before appending a question mark.
    aliaz = prop.to_s[/^(is_)?(\w+)/, 2] << '?'
    delegate_to_property(aliaz, prop)
  end
end

#delegate_to_property(aliaz, property) ⇒ Object (private)

Defines methods aliaz and aliaz= which calls the standard attribute and attribute= accessor methods, resp. Calling rather than aliasing the attribute accessor allows the aliaz accessor to reflect a change to the attribute accessor.



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# File 'lib/jinx/metadata/introspector.rb', line 175

def delegate_to_property(aliaz, property)
  ra, wa = property.accessors
  if aliaz == ra then raise MetadataError.new("Cannot delegate #{self} #{aliaz} to itself.") end
  define_method(aliaz) { send(ra) }
  define_method("#{aliaz}=".to_sym) { |value| send(wa, value) }
  register_property_alias(aliaz, property.attribute)
end

#introspect ⇒ Object

Defines the Java attribute access methods, e.g. study_protocol and studyProtocol. A boolean attribute is provisioned with an additional reader alias, e.g. available? for is_available.

Each Java property attribute delegates to the Java attribute getter and setter. Each standard attribute delegates to the Java property attribute. Redefining these methods results in a call to the redefined method. This contrasts with a Ruby alias, where the alias remains bound to the original method body.



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# File 'lib/jinx/metadata/introspector.rb', line 38

def introspect
  # Set up the attribute data structures; delegates to Propertied.
  init_property_classifiers
  logger.debug { "Introspecting #{qp} metadata..." }
  # check for method conflicts
  conflicts = instance_methods(false) & Resource.instance_methods(false)
  unless conflicts.empty? then
    logger.warn("#{self} methods conflict with #{Resource} methods: #{conflicts.qp}")
  end
  # If this is a Java class rather than interface, then define the Java property
  # attributes.
  if Class === self then
    # the Java attributes defined by this class with both a read and a write method
    pds = property_descriptors(false)
    # Define the standard Java attribute methods.
    pds.each { |pd| define_java_property(pd) }
  end
  # Mark this class as introspected.
  @introspected = true
  logger.debug { "Introspection of #{qp} metadata complete." }
  self
end

#introspected? ⇒ Boolean

Returns whether this class has been introspected.

Returns:

  • (Boolean) —

    whether this class has been introspected



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# File 'lib/jinx/metadata/introspector.rb', line 13

def introspected?
  !!@introspected
end

#wrap_java_date_property(property) ⇒ Object (private)

Adds a Java-Ruby Date filter to the given Date property Ruby access methods. The reader returns a Ruby date. The writer sets a Java date.



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# File 'lib/jinx/metadata/introspector.rb', line 118

def wrap_java_date_property(property)
  ra, wa = property.accessors
  jra, jwa = property.java_accessors
  
  # filter the attribute reader
  define_method(ra) do
    value = send(jra)
    Java::JavaUtil::Date === value ? value.to_ruby_date : value
  end
  
  # filter the attribute writer
  define_method(wa) do |value|
    value = Java::JavaUtil::Date.from_ruby_date(value) if ::Date === value
    send(jwa, value)
  end

  logger.debug { "Filtered #{qp} #{ra} and #{wa} methods with Java Date <-> Ruby Date converter." }
end

#wrap_java_property(property) ⇒ Object (private)

Adds a filter to the given property access methods if it is a String or Date.



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# File 'lib/jinx/metadata/introspector.rb', line 95

def wrap_java_property(property)
  pd = property.property_descriptor
  if pd.property_type == Java::JavaLang::String.java_class then
    wrap_java_string_property(property)
  elsif pd.property_type == Java::JavaUtil::Date.java_class then
    wrap_java_date_property(property)
  end
end

#wrap_java_string_property(property) ⇒ Object (private)

Adds a number -> string filter to the given String property Ruby access methods.



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# File 'lib/jinx/metadata/introspector.rb', line 105

def wrap_java_string_property(property)
  ra, wa = property.accessors
  jra, jwa = property.java_accessors
  # filter the attribute writer
  define_method(wa) do |value|
    stdval = Math.numeric?(value) ? value.to_s : value
    send(jwa, stdval)
  end
  logger.debug { "Filtered #{qp} #{wa} method with non-String -> String converter." }
end