Diploma Thesis Santiago Gómez Sáez - IAAS

6.2. NoSQL Support Implementation
which use its libraries. During the activation process of this OSGi bundle, an instance of
the component is created and registered in the Camel registry. Camel endpoints containing
in its URI the jdbccdasmix component create an instance of the JdbcCdasmixComponent class.
The original Camel-jdbc component requires the user to specify the data source name in the
endpoint URI, and its properties in the bean configuration. However, we do not require
the explicit description of the data source in the URI, as the component retrieves it from the
NMF, and creates it dynamically. The JdbcCdasmixEndpoint class creates an instance of the
producer endpoint, the JdbcCdasmixProducer. The JdbcCdasmixProducer includes the main logic
of the component. When a NMF is received in the jdbccdasmix endpoint, its properties are
extracted and analyzed, the connection to the backend database is established, the message
is demarshaled, the request on the database system is performed, the response from the
database system is marshaled into the NMF, and forwarded back to the endpoint which
created the exchange. The response’s meta-data is stored in the properties section of the NMF,
while the data is stored in the attachment section of the NMF. The storage of attachments in
the NMF through the Camel API requires the storage of the data in a class which implement
the javax.activation.DataSource class. Threfore, we implement two different classes which
implement it, and store different data: the data retrieved from the backend database system
(when success), or the error messages (when an error occurs). Operations on different backend
database systems in one message exchange are considered atomic. If one backend database
system answers with an error, the message exchange status is set to error, and forwarded to
the endpoint which created the message exchange.
The support of JDBC in a custom component and a unique endpoint URI prefix allows
the developers to use the existing Camel-jdbc component for their non multi-tenant aware
connections.
6.2. NoSQL Support Implementation
The prototype requirements described in Chapter 4 specify the need of support to NoSQL
Cloud data stores. In Chapter 5 we present a design for accessing backend NoSQL Cloud data
stores via a standardized protocol which is supported in most of the data stores interfaces:
JSON over HTTP. Gomez [Sá12] and Muhler [Muh12] extend the ServiceMix-http JBI BC in
order to provide multi-tenancy awareness at the communication level. We reuse and extend
the BC to support the communication protocol required in this diploma thesis.
6.2.1. Multi-tenant ServiceMix HTTP Binding Component
As discussed in previous chapters, the ServiceMix-mt JBI BC implements multi-tenancy
awareness for the HTTP communication protocol. However, the multi-tenancy awareness
supported ensures endpoint isolation at the tenant level, but not at the user level. Ensuring
tenant isolation in a system which connects to multiple tenant’s databases, and is accessed by
multiple tenant’s users, is not enough. Therefore, we modify the operations implemented in
Muhler’s approach [Muh12], in order to ensure tenant and user isolation.
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