Selection

Overview

CppGraph© provides powerful mechanisms to locate objects in a node graph based on arbitrarily complex criteria.

A significant portion of conventional development time is dedicated to providing ways for objects to access other objects. The conventional approach is to hardwire access. A class has a data member pointer that the instantiator is required to pass to its constructor. This approach is limited, inflexible, disruptive, and time consuming.

By contrast, the graph selection approach provides access, at runtime, to any objects in the system. Furthermore, no classes, interfaces, function signatures, or function calls require modification. A single function call dynamically to locate items is all that needs to be added.

Selections

A selection operation provides either a collection of handles, or a single handle, to one of the following types of objects:

• node.
• node link.
• property.
• property link.

Select Operations

A select operation is a query provided by:

• node member functions.
• node link member functions.
• node class member functions.

The types of select operation are:

• Multiple Select
  • A collection of handles is returned.
  • The caller specifies whether the search is 1 level deep or all levels deep.
  • The caller may specify a filter.
  • The caller specifies the required multiplicity of the resulting collection:
    • zero or more.
    • 1 or more.
    • exactly 1.
  • The caller specifies whether or not an assert is triggered if the specified multiplcity is violated.
  • An empty collection is returned if the specified multiplicity is violated.
• Single Select
  • A handle to an item, or nullptr is returned.
  • The caller specifies whether the search is:
    • 1 level deep.
    • all levels deep..
  • The caller may specify a filter.
  • The caller specifies whether or not an assert is triggered if there are no matching items.
  • An assert is triggered if there is more than 1 matching item.
  • nullptr is returned if there are no matching items.

Select Functions

The following sets of member functions include functions that perform select operations:

• Selecting nodes from all existing node instances in the current thread.
• Selecting nodes specified by a relative path starting at a specified node.
• Selecting properties specified by a relative path starting at a specified node.
• Selecting descendant nodes of a specified node.
• Selecting ancestor nodes of a specified node.
• Selecting descendant node links of a specified node.
• Selecting ancestor node links of a specified node.
• Selecting properties of nodes where the nodes are the endpoints of a specified path starting at a specified node.
• Selecting properties of a specified node or node link.
• Selecting property links of a specified node or node link.