The World according to the App layer

What the App layer does

* Facilitate the flow of information between view and data representations (which have different requirements).

* Presenting information as to the configuration of the system to the UI and service layers, and receive information from them.

* Allowing a point of extension and integration in terms of extra data feeds and storage mechanisms, extendible through a plugin-like mechanism.

The Code

CSPi vs CSP

The app layer is split into

CSP = CollectionSpace PluginsCSPi = CollectionSpace Plugin implementations

The use of implementations allow the App layer to easily grow and accommodate multiple data sources and structures

CSPi Schema

Parses cspace-config.xml and makes it available to all areas of the App layer

CSPI-Schema / Spec

cspace-config.xml

CSPi WebUI

Deals with all calls from the UI and works out what to do with them

CSPi-WebUI/WebUI.java

CSPi-WebUI / WebLoginStatus

CSPi-WebUI / UISpec

CSPi-WebUI / RecordRead

RecordRead.java

/chain/objects/ef505766-b2be-49bc-bfe8

WebUI Spec

Cspace-config.xml

TermsUsed RecordDataRelatedObjects

/relations/subject/*/

/relations/csid

/{recordtype}/{csid}

/{recordtype}/{csid}/authorityrefs

/{recordtype}/{authcsid}/items/{itemscsid}

/{csid}

JSONObject

JSONObject

/chain/objects/ef505766-b2be-49bc-bfe8

APP LAYER

RESTFul toService Layer in CSPi-Services

JSONObjectJSONObject

CSPi Services

Talks to the service layer and finds out everything the UI needs to know

CSPi-Services / ServiceStorageGenerator

CSPi-Services / RecordStorage

Storage

XmlJsonConversion

A more complex example

Important to note that that filePath sent from the webUI is not necessarily the URL that the service layer needs and is more like a flag which helps the app layer decide what to do with it once it hits CSPi Services as sometimes we need to make multiple calls to the Service Layers RestFul services to get all the information needed

CSPi-WebUI/ RecordRead

CSPi-WebUI/ RecordRead

In Summary

Data Flow

Berkeley

Services

Toronto UI

MagicCSPi-

Services

CSPi-WebUI

RESTful XML/cspace-services/xxx/x

JSON/chain/xxx/xxx

App Layer

CSPi-Schema

cspace-config.xml

CSPi-Schema

This is responsible for maintaining the "core" configuration.

Many plugins will just be able to use the configuration managed by this plugin, and not have their own extensions at all.

Spec.java is the main class and is initialised only once at the startup and will parse the config against a set of “rules”.

Rules can be added in any class, any where in the system – which means that you can override specific rules for different implementations if needed.

CSPi-WebUI Main

WebUI.java maps urls to classes

Record/authority/relate/userroles/userdetails

All Fundamentally the same

Have 4 classes

CreateUpdate Delete Read Search

Nuispec

Magic that makes the uispecs for the UI layer from the config.

CSPi-Services XXXStorage

AutocreateJSON

UpdateJSON

DeleteJSON

GetPathsJSON

Everything else is mostly to do with caching, mini records and differences between the structure of XML that the service layer sends us for different data type

MiniRecords are summary records created (hopefully) only from the subset of data pulled when retrieving lists of data from the service layer. This should be enough data to populate RH columns and Search results.

The app layer internally talks to itself with JSON(hence why all the functions have JSON in the name)