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Note: To store values that may be accessed across multiple pages, uses a session state object.

Making a field persistent is accomplished with the Persist annotation. Again, this does not refer to database persistence, it refers to session persistance.

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For each component, the meta-data property tapestry.persistence-strategy is checked. This can be specified using the Meta annotation.

If the value is non-blank, then that strategy is used. This allows a component to control the persistence strategy used inside any sub-components (that don't explicitly use a different strategy).

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You can mark your own session objects as immutable using the ImmutableSessionPersistedObject annotation.

OptimizedSessionPersistedObject

The OptimizedSessionPersistedObject interface allows an object to control this behavior. An object with this interface can track when its mutable state changes. Typically, you should extend from the BaseOptimizedSessionPersistedObject base class.

SessionPersistedObjectAnalyzer

The SessionPersistedObjectAnalyzer service is ultimately responsible for determining whether a session persisted object is dirty or not (dirty meaning in need of a restore into the session). This is an extensible service where new strategies, for new classes, can be introduced.