+
+
+
+
+
+
Overview
+
+
Strolch is an open source component based software agent written in Java and can be compared, in a light
+ sense, with the Java EE stack: Strolch takes care of persistence, implements Services for use cases, Commands
+ as re-usable algorithms and has a parameterized data model.
+
+
Strolch has an intrinsic understanding for mandates, which are called realms so that a single agent can be
+ used to implement applications with multiple users/customers for instance in SaaS environments.
+
+
The parameterized data model consists of three top level objects, Resources, Orders and Activities. These
+ objects can have any number of ParameterBags which in turn can have any number of Parameters on them. This
+ allows for a very dynamic modelling of data structures including modification at run time. Multiple ready to
+ use Parameter types are already implemented which handle the primitive types in Java including ListParameters
+ for collections of these primitive types.
+
+
One of the main features of the Strolch agent, is that persistence is handled transparently and the user must
+ not be worried about databases and the likes. Currently there are two implementations for persisting the
+ Strolch model, a PostgreSQL and an XML file persistence. Currently both persistence layers persist the data
+ by converting to XML and storing it into the database. The XML file persistence stores each object in its own
+ file.
+
+
The agent itself has a small memory footprint and requires very few components to start. For the agent to be
+ useful it needs additional functionality which is implemented in StrolchComponents. Each component is
+ registered via its Java interface on the agent and is bound to the life cycle of the agent. When the agent is
+ started, these components can be retrieved and used to perform any number of functionalities. This is the
+ preferred way to extend the Strolch agent. There are a number of components already implemented, e.g. the
+ ServiceHandler which executes Services in a controlled fashion and can validate authorized access to these
+ services.
+
+
No software product is complete without a system for authentication and authorization. Strolch implements
+ this by using the Privilege framework which has been written by Robert von Burg. The standard ServiceHandler
+ detects the existence of the PrivilegeHandler and then validates that the user has authorization to perform
+ the service. This framework is implemented as its own Strolch component, thus can be retrieved at any time
+ during execution to perform fine grained and special authorization validation.
+
+
Motivation
+
+
A question often asked is why create Strolch. What are its benefits in contrast to using Java SE with an
+ OR-Mapper like Hibernate, or using Java EE on JBoss or Glassfish? Especially since many of the features
+ existing in those stacks needed to be re-created in Strolch.
+
+
The first answer to this question is that those systems are often overly complicated and bloated. Java SE
+ with Hibernate certainly is a viable option when it comes to being light-weightier but Hibernate, even though
+ it is supposed to, often fails to truly help remove the need to really understand an RDBMS. Often enough
+ Hibernate will just get in the way of the most important part of development: writing the business code.
+ Being an OR-Mapper which is supposed to implement all the nitty-gritty details of an RDBMS system, Hibernate,
+ and JPA for that matter, still often has the developer go back to understanding these details.
+
+
Strolch tries a different approach to persistence. Instead of writing pojos/entities, Strolch's model has the
+ concept that each element's attributes are part of a composition pattern: each attribute is its own object
+ and thus can be dynamically changed at runtime, but also makes persistence of such an element generic.
+ Instead of having fixed attributes for a concrete class, these parameters are stored in a map and are
+ accessed through the parameter's ID.
+
+
Assigning an ID to an attribute for accessing of course brings its own downsides, i.e. the parameter might
+ simply not be there, when being accessed. This is certainly an issue that the developer must handle, when
+ implementing a project using Strolch, but allows the developer to not need to worry about persistence, as
+ this is generically handled.
+
+
Since the persistence is generically handled, and Strolch stays lightweight on its requirements at runtime,
+ the developer can quickly get down to what is important for business value: Writing the business logic and
+ the presentation layer. Here too Strolch tries to help the developer by bringing in concepts which are easy
+ to follow: Use cases are implemented as Services, and re-usable business logic is put into Commands.
+
+
There will be reasons against using Strolch, as there will be against using the Java EE stack, or an
+ OR-Mapper or even the Java ecosystem for that fact. Important is to note, that the concepts behind Strolch
+ are nothing new, but have been implemented in at least two previous proprietary products. Since those
+ products are not accessible to the public, it was decided that a re-implementation might be of use to the
+ programming community at large.
+
+
Currently there is at least one company using Strolch in a commercial project which helps drive Strolch's
+ development and further motivates its existence.
+
+
Strolch is an open source project and licensed under the Apache License 2.0.
+
+
Technologoy
+
+
Strolch is written in Java and is programmed against the JDK 8. Strolch runs on any JRE 8 compliant
+ environment. Strolch is tested on the Oracle JRE 8.
+
+
Dependencies
+
+
Strolch strives to use as few external dependencies as possible, so that the Strolch runtime is not bloated
+ unnecessarily. The following list of Strolch dependencies is a summary and was created using mvn
+ dependency:tree on the strolch_minimal project for release 1.6.47.
+
+
Logging
+
+ - org.slf4j:slf4j-api:jar:1.7.25
+ - ch.qos.logback:logback-classic:jar:1.2.3
+ - ch.qos.logback:logback-core:jar:1.2.3
+
+
+
Utils
+
+ - javax.mail:javax.mail-api:jar:1.6.0
+ - com.sun.mail:javax.mail:jar:1.6.0
+ - javax.activation:activation:jar:1.1
+
+
+
Testing
+
+ - junit:junit:jar:4.12
+ - org.hamcrest:hamcrest-core:jar:1.3
+ - org.hamcrest:hamcrest-library:jar:1.3
+ - org.mockito:mockito-core:jar:2.0.8-beta
+ - org.objenesis:objenesis:jar:2.1
+
+
+
Model
+
+ - com.google.code.gson:gson:jar:2.8.2
+
+
+
SOQL
+
+ - org.abego.treelayout:org.abego.treelayout.core:jar:1.0.3
+ - org.antlr:antlr-runtime:jar:3.5.2
+ - org.antlr:antlr4-runtime:jar:4.7
+ - org.antlr:antlr4:jar:4.7
+ - org.antlr:ST4:jar:4.0.8
+ - org.glassfish:javax.json:jar:1.0.4
+ - com.ibm.icu:icu4j:jar:58.2
+
+
+
PostgreSQL
+
+ - com.zaxxer:HikariCP:jar:2.7.1
+ - org.postgresql:postgresql:jar:42.1.4
+
+
+
REST
+
+ - javax.annotation:javax.annotation-api:jar:1.3.1
+ - javax.servlet:javax.servlet-api:jar:3.1.0
+ - javax.ws.rs:javax.ws.rs-api:jar:2.1
+
+
+
REST testing
+
+ - javax.validation:validation-api:jar:1.1.0.Final
+ - org.glassfish.grizzly:grizzly-framework:jar:2.3.28
+ - org.glassfish.grizzly:grizzly-http-server:jar:2.3.28
+ - org.glassfish.grizzly:grizzly-http-servlet:jar:2.3.28
+ - org.glassfish.grizzly:grizzly-http:jar:2.3.28
+ - org.glassfish.hk2:hk2-api:jar:2.5.0-b32
+ - org.glassfish.hk2:hk2-locator:jar:2.5.0-b32
+ - org.glassfish.hk2:hk2-utils:jar:2.5.0-b32
+ - org.glassfish.hk2:osgi-resource-locator:jar:1.0.1
+ - org.glassfish.hk2.external:aopalliance-repackaged:jar:2.5.0-b32
+ - org.glassfish.hk2.external:javax.inject:jar:2.5.0-b32
+ - org.glassfish.jersey.bundles.repackaged:jersey-guava:jar:2.25.1
+ - org.glassfish.jersey.containers:jersey-container-grizzly2-http:jar:2.25.1
+ - org.glassfish.jersey.containers:jersey-container-grizzly2-servlet:jar:2.25.1
+ - org.glassfish.jersey.containers:jersey-container-servlet-core:jar:2.25.1
+ - org.glassfish.jersey.containers:jersey-container-servlet:jar:2.25.1
+ - org.glassfish.jersey.core:jersey-client:jar:2.25.1
+ - org.glassfish.jersey.core:jersey-common:jar:2.25.1
+ - org.glassfish.jersey.core:jersey-server:jar:2.25.1
+ - org.glassfish.jersey.media:jersey-media-jaxb:jar:2.25.1
+ - org.glassfish.jersey.test-framework:jersey-test-framework-core:jar:2.25.1
+ - org.javassist:javassist:jar:3.20.0-GA
+
+
+
+
API
+
+
Check out the API page to see how to use Strolch.
+
+
+
+
+
+
+
-
Overview
+
Strolch in short
-
Strolch is an open source component based software agent written in Java and can be compared, in a light
- sense, with the Java EE stack: Strolch takes care of persistence, implements Services for use cases, Commands
- as re-usable algorithms and has a parameterized data model.
-
-
Strolch has an intrinsic understanding for mandates, which are called realms so that a single agent can be
- used to implement applications with multiple users/customers for instance in SaaS environments.
-
-
The parameterized data model consists of three top level objects, Resources, Orders and Activities. These
- objects can have any number of ParameterBags which in turn can have any number of Parameters on them. This
- allows for a very dynamic modelling of data structures including modification at run time. Multiple ready to
- use Parameter types are already implemented which handle the primitive types in Java including ListParameters
- for collections of these primitive types.
-
-
One of the main features of the Strolch agent, is that persistence is handled transparently and the user must
- not be worried about databases and the likes. Currently there are two implementations for persisting the
- Strolch model, a PostgreSQL and an XML file persistence. Currently both persistence layers persist the data
- by converting to XML and storing it into the database. The XML file persistence stores each object in its own
- file.
-
-
The agent itself has a small memory footprint and requires very few components to start. For the agent to be
- useful it needs additional functionality which is implemented in StrolchComponents. Each component is
- registered via its Java interface on the agent and is bound to the life cycle of the agent. When the agent is
- started, these components can be retrieved and used to perform any number of functionalities. This is the
- preferred way to extend the Strolch agent. There are a number of components already implemented, e.g. the
- ServiceHandler which executes Services in a controlled fashion and can validate authorized access to these
- services.
-
-
No software product is complete without a system for authentication and authorization. Strolch implements
- this by using the Privilege framework which has been written by Robert von Burg. The standard ServiceHandler
- detects the existence of the PrivilegeHandler and then validates that the user has authorization to perform
- the service. This framework is implemented as its own Strolch component, thus can be retrieved at any time
- during execution to perform fine grained and special authorization validation.
-
-
Motivation
-
-
A question often asked is why create Strolch. What are its benefits in contrast to using Java SE with an
- OR-Mapper like Hibernate, or using Java EE on JBoss or Glassfish? Especially since many of the features
- existing in those stacks needed to be re-created in Strolch.
-
-
The first answer to this question is that those systems are often overly complicated and bloated. Java SE
- with Hibernate certainly is a viable option when it comes to being light-weightier but Hibernate, even though
- it is supposed to, often fails to truly help remove the need to really understand an RDBMS. Often enough
- Hibernate will just get in the way of the most important part of development: writing the business code.
- Being an OR-Mapper which is supposed to implement all the nitty-gritty details of an RDBMS system, Hibernate,
- and JPA for that matter, still often has the developer go back to understanding these details.
-
-
Strolch tries a different approach to persistence. Instead of writing pojos/entities, Strolch's model has the
- concept that each element's attributes are part of a composition pattern: each attribute is its own object
- and thus can be dynamically changed at runtime, but also makes persistence of such an element generic.
- Instead of having fixed attributes for a concrete class, these parameters are stored in a map and are
- accessed through the parameter's ID.
-
-
Assigning an ID to an attribute for accessing of course brings its own downsides, i.e. the parameter might
- simply not be there, when being accessed. This is certainly an issue that the developer must handle, when
- implementing a project using Strolch, but allows the developer to not need to worry about persistence, as
- this is generically handled.
-
-
Since the persistence is generically handled, and Strolch stays lightweight on its requirements at runtime,
- the developer can quickly get down to what is important for business value: Writing the business logic and
- the presentation layer. Here too Strolch tries to help the developer by bringing in concepts which are easy
- to follow: Use cases are implemented as Services, and re-usable business logic is put into Commands.
-
-
There will be reasons against using Strolch, as there will be against using the Java EE stack, or an
- OR-Mapper or even the Java ecosystem for that fact. Important is to note, that the concepts behind Strolch
- are nothing new, but have been implemented in at least two previous proprietary products. Since those
- products are not accessible to the public, it was decided that a re-implementation might be of use to the
- programming community at large.
-
-
Currently there is at least one company using Strolch in a commercial project which helps drive Strolch's
- development and further motivates its existence.
-
-
Strolch is an open source project and licensed under the Apache License 2.0.
-
-
Technologoy
-
-
Strolch is written in Java and is programmed against the JDK 8. Strolch runs on any JRE 8 compliant
- environment. Strolch is tested on the Oracle JRE 8.
-
-
Dependencies
-
-
Strolch strives to use as few external dependencies as possible, so that the Strolch runtime is not bloated
- unnecessarily. The following list of Strolch dependencies is a summary and was created using mvn
- dependency:tree on the strolch_minimal project for release 1.6.47.
-
-
Logging
+
Strolch is framework for developing Software. It's main features are:
- - org.slf4j:slf4j-api:jar:1.7.25
- - ch.qos.logback:logback-classic:jar:1.2.3
- - ch.qos.logback:logback-core:jar:1.2.3
-
-
-
Utils
-
- - javax.mail:javax.mail-api:jar:1.6.0
- - com.sun.mail:javax.mail:jar:1.6.0
- - javax.activation:activation:jar:1.1
-
-
-
Testing
-
- - junit:junit:jar:4.12
- - org.hamcrest:hamcrest-core:jar:1.3
- - org.hamcrest:hamcrest-library:jar:1.3
- - org.mockito:mockito-core:jar:2.0.8-beta
- - org.objenesis:objenesis:jar:2.1
-
-
-
Model
-
- - com.google.code.gson:gson:jar:2.8.2
-
-
-
SOQL
-
- - org.abego.treelayout:org.abego.treelayout.core:jar:1.0.3
- - org.antlr:antlr-runtime:jar:3.5.2
- - org.antlr:antlr4-runtime:jar:4.7
- - org.antlr:antlr4:jar:4.7
- - org.antlr:ST4:jar:4.0.8
- - org.glassfish:javax.json:jar:1.0.4
- - com.ibm.icu:icu4j:jar:58.2
-
-
-
PostgreSQL
-
- - com.zaxxer:HikariCP:jar:2.7.1
- - org.postgresql:postgresql:jar:42.1.4
-
-
-
REST
-
- - javax.annotation:javax.annotation-api:jar:1.3.1
- - javax.servlet:javax.servlet-api:jar:3.1.0
- - javax.ws.rs:javax.ws.rs-api:jar:2.1
-
-
-
REST testing
-
- - javax.validation:validation-api:jar:1.1.0.Final
- - org.glassfish.grizzly:grizzly-framework:jar:2.3.28
- - org.glassfish.grizzly:grizzly-http-server:jar:2.3.28
- - org.glassfish.grizzly:grizzly-http-servlet:jar:2.3.28
- - org.glassfish.grizzly:grizzly-http:jar:2.3.28
- - org.glassfish.hk2:hk2-api:jar:2.5.0-b32
- - org.glassfish.hk2:hk2-locator:jar:2.5.0-b32
- - org.glassfish.hk2:hk2-utils:jar:2.5.0-b32
- - org.glassfish.hk2:osgi-resource-locator:jar:1.0.1
- - org.glassfish.hk2.external:aopalliance-repackaged:jar:2.5.0-b32
- - org.glassfish.hk2.external:javax.inject:jar:2.5.0-b32
- - org.glassfish.jersey.bundles.repackaged:jersey-guava:jar:2.25.1
- - org.glassfish.jersey.containers:jersey-container-grizzly2-http:jar:2.25.1
- - org.glassfish.jersey.containers:jersey-container-grizzly2-servlet:jar:2.25.1
- - org.glassfish.jersey.containers:jersey-container-servlet-core:jar:2.25.1
- - org.glassfish.jersey.containers:jersey-container-servlet:jar:2.25.1
- - org.glassfish.jersey.core:jersey-client:jar:2.25.1
- - org.glassfish.jersey.core:jersey-common:jar:2.25.1
- - org.glassfish.jersey.core:jersey-server:jar:2.25.1
- - org.glassfish.jersey.media:jersey-media-jaxb:jar:2.25.1
- - org.glassfish.jersey.test-framework:jersey-test-framework-core:jar:2.25.1
- - org.javassist:javassist:jar:3.20.0-GA
+ - Complete persisted data model:
+
+ - Parameters and values by time
+ - Resources, Orders with arbitrary parameter grouping
+ - Activity/Action hierarchy with arbitrary depth
+ - Policies for delegation
+ - JSON as well as XML transformation
+ - Locator API
+
+
+ - Transactions with pessimistic locking and optional
+ read-locking
+ - Search API
+ - Component based
+ - Deeply integrated privilege handling
+ - Fully in-memory
+ - Persisted auditing, versioning, operations log
+ - DAOs for file system or PostgreSQL, easily extended
+ - Execution framework
+ - Service / Command oriented
+ - Reporting API configured by Resource objects
+ - REST API for data access
+ - WebComponents UI for
+
+ - Inspector
+ - Users
+ - Roles
+ - Operations Log
+ - Login Screen
+ - Jobs
+
+
+ - runs on plain old Java SE
-
API
+
Strolch Intro
+
+
It is a different framework to Spring and other similar type of Java frameworks, as the model is defined as
+ an abstract model, where you always have the same three types of objects: Resources, Orders and Activities.
+ The fields are mapped as Parameter objects, of which the important primitives are available.
+
+
The nice part about this framework is, that you can be up and ready in a matter of minutes, and start
+ building your project immediately in that you open your favourite XML editor and start modelling your
+ data.
+
+
Once your data is defined, you write your business logic in the form of Services, Commands and Searches.
+ There are many predefined services and commands to manipulate the object model, so that you write your own
+ services when you need to enforce special business rules.
+
+
Through the use of Policy objects, you decouple algorithms from your object model, so that at runtime you can
+ change the behaviour, or easily implement different behaviour depending on your use-case. For instance you
+ might have a simple billing service which performs a few preparatory steps, and then calls the configured
+ billing policy to execute the billing depending on the customer, the warehouse, etc.
+
+
And of course persistence is as simple as configuring the persistence handler, pointing to your RDBMS and
+ then setting the mode to CACHED. For you as a developer there is no more thinking in terms of SQL etc., as
+ this is completely hidden from the developer. There is even a simple file persistence layer if you are
+ running IoT devices.
+
+
The runtime can be just about anything. Usually it is run inside an Apache Tomcat instance as a webapp, as a
+ WEB UI has been required for all current Strolch projects. You could just as well use a main class. Accessing
+ the Strolch Agent remotely is usually done through REST.
+
+
Strolch is being actively developed, and customers constantly give us reasons to improve and extend the
+ framework. There is a Polymer Inspector component which makes it easy to see and manipulate the actual data.
+ The new Search API makes it really easy to query your data.
+
+
Yes, Strolch is different, but the concept has come out of the planning and execution segment, and has been
+ refined over the years until it has become what it is today.
+
+
API
Check out the API page to see how to use Strolch.
+
More to motivation etc.
+