Patterns of Enterprise Application Architecture

Splits user interface interaction into three distinct roles.

An object that handles a request for a specific page or action on a Web site.

A controller that handles all requests for a Web site.

Renders information into HTML by embedding markers in an HTML page.

A view that processes domain data element by element and transforms it into HTML.

Turns domain data into HTML in two steps: first by forming some kind of logical page, then rendering the logical page into HTML.

A centralized point for handling screen navigation and the flow of an application.

Provides a coarse-grained facade on fine-grained objects to improve efficiency over a network.

An object that carries data between processes in order to reduce the number of method calls.

Prevents conflicts between concurrent business transactions by detecting a conflict and rolling back the transaction.

Prevents conflicts between concurrent business transactions by allowing only one business transaction at a time to access data.

Locks a set of related objects with a single lock.

Allows framework or layer supertype code to acquire offline locks.

Stores session state on the client.

Keeps the session state on a server system in a serialized form.

Stores session data as committed data in the database.

An object that encapsulates access to an external system or resource.

An object that sets up a communication between two independent objects.

A type that acts as the supertype for all types in its layer.

Defines an interface in a separate package from its implementation.

A well-known object that other objects can use to find common objects and services.

A small simple object, like money or a date range, whose equality isn't based on identity.

Represents a monetary value.

A subclass that provides special behavior for particular cases.

Links classes during configuration rather than compilation.

Removes dependence upon problematic services during testing. WSDL

An in-memory representation of tabular data.

Organizes business logic by procedures where each procedure handles a single request from the presentation.

An object model of the domain that incorporates both behavior and data.

A single instance that handles the business logic for all rows in a database table or view.

Defines an application's boundary with a layer of services that establishes a set of available operations and coordinates the application's response in each operation.

An object that acts as a Gateway (466) to a database table. One instance handles all the rows in the table.

An object that acts as a Gateway (466) to a single record in a data source. There is one instance per row.

An object that wraps a row in a database table or view, encapsulates the database access, and adds domain logic on that data.

A layer of Mappers (473) that moves data between objects and a database while keeping them independent of each other and the mapper itself.

Maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency problems.

Ensures that each object gets loaded only once by keeping every loaded object in a map. Looks up objects using the map when referring to them.

An object that doesn't contain all of the data you need but knows how to get it.

Saves a database ID field in an object to maintain identity between an in-memory object and a database row.

Maps an association between objects to a foreign key reference between tables.

Saves an association as a table with foreign keys to the tables that are linked by the association.

Has one class perform the database mapping for a child class.

Maps an object into several fields of another object's table.

Saves a graph of objects by serializing them into a single large object (LOB), which it stores in a database field.

Represents an inheritance hierarchy of classes as a single table that has columns for all the fields of the various classes.

Represents an inheritance hierarchy of classes with one table for each class.

Represents an inheritance hierarchy of classes with one table per concrete class in the hierarchy.

A structure to organize database mappers that handle inheritance hierarchies.

Holds details of object-relational mapping in metadata.

An object that represents a database query.

Mediates between the domain and data mapping layers using a collection-like interface for accessing domain objects.