Bug 512054 - Investigate how to support accessing a single transaction policy from multiple handlers
Summary: Investigate how to support accessing a single transaction policy from multipl...
Status: NEW
Alias: None
Product: GEF
Classification: Tools
Component: GEF MVC (show other bugs)
Version: 1.1.0   Edit
Hardware: All All
: P3 normal (vote)
Target Milestone: ---   Edit
Assignee: gef-inbox CLA
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Reported: 2017-02-10 12:04 EST by Matthias Wienand CLA
Modified: 2017-05-22 10:28 EDT (History)
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Description Matthias Wienand CLA 2017-02-10 12:04:41 EST 
Currently, when multiple interaction policies access the same transaction policy to perform their actions, the transaction policy is initialized more than once, which leads to an IllegalStateException ("already initialized").

This unfortunate constellation can be observed within the MVC Logo Example when interleaving touch gestures for panning and zooming (PanOrZoomOnScrollPolicy, ZoomOnPinchSpreadPolicy).

A workaround is to combine the multiple interaction policies to a single interaction policy that implements the individual interaction interfaces. This combined policy can then ensure that an underlying transaction policy is only once initialized.

We need to investigate how to simplify the combination of interaction policies that use the same transaction policy.