crossportlet

Crossportlet is a term used in portal and portlet architecture to describe mechanisms that enable two or more portlets to interact, share data, or coordinate behavior on a single page or across portals. The aim is to create integrated user interfaces where portlets can respond to each other’s state or events without tight coupling.

In practice, crossportlet communication is achieved through several patterns. Inter-portlet events allow a portlet to publish a message that other portlets on the page can receive and react to. Public render parameters provide named values that multiple portlets can read or write during the render phase, enabling coordinated rendering without direct references between portlets. Some platforms also support shared data sources or session-scoped state to facilitate coordination, and modern frameworks may expose REST or other service-based APIs for cross-portlet interactions.

Standards and implementations of crossportlet functionality are primarily associated with the Portlet API. Inter-portlet events and public render parameters were introduced to support loose coupling and page-level coordination. Web Services for Remote Portlets (WSRP) offers cross-portal interoperability by enabling remote portlets to participate in a shared portal experience. Popular portal frameworks, such as Liferay, GateIn, and Apache Pluto, provide built-in support for these mechanisms, while custom implementations may rely on backend services or additional messaging layers.

Common use cases include synchronized filtering and navigation across portlets, shared selections that update multiple components, and dynamic UI adaptation based on user actions. Design considerations include security, performance, lifecycle management, and version compatibility to avoid unintended data exposure or coupling.

See also: inter-portlet communication, public render parameters, JSR-286, WSRP, portal frameworks.