mvc: Dynamic List use case - allow collections/arrays to grow [SPR-4728]

[spring-projects-issues]

Dmitry Platonov opened SPR-4728 and commented

There's a popular use case (search forum for 'dynamic list') for implementing dynamic lists on web pages.

The most common approach is to create hacks in controller to initialize collections/arrays command object properties before binding - trim or grow collections/arrays properties to some calculated size. This will allow binder to bind props[0].name, props[1].name request params to command object even if original command.getProps() returns null or empty collection/array.

The approach must be used EACH controller which wants to work with dynamically added fields.

This could be fixed in SINGLE place - in BeanWrapperImpl#getPropertyValue(), which could allow collection/array to grow instead of simply (Array.get(value, Integer.parseInt(key)), list.get(Integer.parseInt(key)))

Or could we somehow override that method?

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Affects: 2.5.3

Issue Links:

• Option to expose empty value instead of NullValueInNestedPathException [SPR-1671] #6368 Option to expose empty value instead of NullValueInNestedPathException
• Data Binder: Auto-grow collections as needed to support nested property binding [SPR-6033] #10702 Data Binder: Auto-grow collections as needed to support nested property binding

7 votes, 9 watchers