https://github.com/fluentcodes/elasticobjects

A java framework using typed JSON for looseless communication of composed objects by one generic endpoint. Functionality is provided by special call objects with a generic execute method. Predefined generic calls for files, JSON, Excel, CSV, databases or templates. Compared with todays RPC its a "Remote Object Call" (ROC) architecture.
https://github.com/fluentcodes/elasticobjects

csv database excel hacktoberfest hacktoberfest2020 java-8 json low-code templates

Last synced: 5 days ago
JSON representation

A java framework using typed JSON for looseless communication of composed objects by one generic endpoint. Functionality is provided by special call objects with a generic execute method. Predefined generic calls for files, JSON, Excel, CSV, databases or templates. Compared with todays RPC its a "Remote Object Call" (ROC) architecture.

• Host: GitHub
• URL: https://github.com/fluentcodes/elasticobjects
• Owner: fluentcodes
• License: apache-2.0
• Created: 2018-10-17T01:30:01.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2023-05-26T22:12:32.000Z (over 1 year ago)
• Last Synced: 2023-07-28T17:32:49.584Z (about 1 year ago)
• Topics: csv, database, excel, hacktoberfest, hacktoberfest2020, java-8, json, low-code, templates
• Language: Java
• Homepage: http://www.elasticobjects.org
• Size: 67.6 MB
• Stars: 0
• Watchers: 1
• Forks: 1
• Open Issues: 7
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
[![Open Source Helpers](https://www.codetriage.com/fluentcodes/elasticobjects/badges/users.svg)](https://www.codetriage.com/fluentcodes/elasticobjects)

> [elasticobjects.org](https://www.elasticobjects.org/examples/ExamplesStart.html) provide a detailed documentation with interactive examples build by template calls. The sources you find in  [example-springboot](example-springboot).

# (EO) Elastic Objects

Elastic Objects is a tiny layer offering path access methods to any java object tree.



The access

to underlying

java objects is mediated by key and

strict object configurations defined by

  ModelConfig.json

and

  FieldConfig.json

in the class path. The configurations become first class citizen to determine type in an object tree.





Embedded

   Call

objects could manipulate the object tree with a generic execute method.

It's a "Remote Object Call" (ROC) architecture instead of RPC concepts.



With the configuration key embedded in json the serialization/deserialization allows

typesafe communication between computers without endpoints or web frameworks.

Embedded in arbitrary text it could initiate complex workflows or compose complex text.

## Core (elastic-objects)

### elastic-objects Module

The [core](elastic-objects) has actually no dependencies beside Log4j and is rather small with a jar size of approximately 90 KB.

    

        org.fluentcodes.projects.elasticobjects

        elastic-objects

        0.9.4

    



mvn repository



### elastic-objects Examples



The following examples you find in

  EOReadmeTest

as runnable tests.

The test object is

  AnObject.



#### Get and Set

Some get and set operations.

    EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new AnObject());

    EOInterfaceScalar child = root.set("test", "myAnObject", "myString");

    

    assertEquals("test", root.get("myAnObject", "myString"));

    assertEquals("test", child.get());

#### Underlying Object



The set method changes the value of  

  AnObject

via its

≡AnObject configuration :



    EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new AnObject());

    root.set("test", "myAnObject", "myString");

    

    AnObject anObject = (AnObject) root.get();

    assertEquals("test", anObject.getMyAnObject().getMyString());    

#### String Path Representation

For all accessors one can use a path string with a "/" delimiter like in a file system. Again we set

the value *test* in the fields [≡AnObject](https://elasticobjects.org/config/ModelConfig/AnObject) and [≡myString](https://elasticobjects.org/config/FieldConfig/myString).

    EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new AnObject());

    EOInterfaceScalar child = root.set("test", "myAnObject/myString");

    

    assertEquals("test", root.get("myAnObject/myString"));

    assertEquals("test", child.get());

#### Remove child

One can remove a branch from the object tree in a path way.

    EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new AnObject());

    EOInterfaceScalar child = root.set("test", "myAnObject/myString");

    

    EO parent = child.remove();

    assertFalse(parent.hasEo("myString"));

    

    AnObject parentObject = (AnObject) parent.get();

    assertNull(parentObject.getMyString());    

#### Field Length Restrictions

The field configuration [≡myString](https://elasticobjects.org/config/FieldConfig/myString) has a max size of 20. It will be checked when setting a value. In this example the value *test01234567890123456789* has the length 24 and produce an exception.

    EoRoot root = EoRoot.ofClass(CONFIG_MAPS, AnObject.class);

    assertEquals(AnObject.class, root.getModelClass());

    Assertions.assertThatThrownBy(

            ()->{root.set("test01234567890123456789", "myString");})

            .isInstanceOf(EoException.class)

            .hasMessageContaining("Problem creating child at '/' with key 'myString' with value 'test01234567890123456789' with message String value for field 'test01234567890123456789' has size 24 bigger than max length 20.");

Interactive example: https://www.elasticobjects.org/examples/AnObjectTooLong.html.

#### Restrictions to a Map



It's possible to add field configurations with a Map as underlying object. In

  ModelConfig.json

the configuration of

≡AnObjectMap

has the field definition

≡myString.

This will be checked within

  ModelConfigMap

.


Here the previous example with "AnObjectMap":

    EoRoot root = EoRoot.ofClassName(CONFIG_MAPS, "AnObjectMap");

    assertEquals(LinkedHashMap.class.getSimpleName(), root.get().getClass().getSimpleName());

    Assertions.assertThatThrownBy(

            ()->{root.set("test01234567890123456789", "myString");})

            .isInstanceOf(EoException.class)

                .hasMessageContaining("Problem creating child at '/' with key 'myString' with value 'test01234567890123456789' with message String value for field 'test01234567890123456789' has size 24 bigger than max length 20.");

Interactive example: https://www.elasticobjects.org/examples/AnObjectMapTooLong.html.

##### Field does not exist

When field definition are set, also names will be checked:

    EoRoot root = EoRoot.ofClassName(CONFIG_MAPS, "AnObjectMap");

    Assertions.assertThatThrownBy(

            ()->{root.set("test", "notValid");})

            .isInstanceOf(EoException.class)

            .hasMessageContaining("Problem creating child at '/' with key 'notValid' with value 'test' with message No field defined for 'notValid'.");

Interactive example: https://www.elasticobjects.org/examples/AnObjectMapFieldNotExists.html.

#### Typed JSON

The default json representation contains keys of the model configuration [≡AnObject](https://elasticobjects.org/config/ModelConfig/AnObject):

        EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new AnObject());

        EOInterfaceScalar child = root.set("test", "myAnObject", "myString");

        assertEquals("{\n" +

                "  \"_rootmodel\": \"AnObject\",\n" +

                "  \"(AnObject)myAnObject\": {\n" +

                "    \"myString\": \"test\"\n" +

                "  }\n" +

                "}", root.toJson());

#### From JSON

This typed json will mapped to the appropriate object class when deserialized:

        EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new AnObject());

        root.set("test", "myAnObject", "myString");

        String json = root.toJson();      

         

        EoRoot rootFromJson = EoRoot.ofValue(CONFIG_MAPS, json);       

        assertEquals(AnObject.class, rootFromJson.get().getClass());

        

        AnObject myAnObject = (AnObject)rootFromJson.get();

        assertEquals("test", myAnObject.getMyAnObject().getMyString());

Interactive example: https://www.elasticobjects.org/examples/AnObjectTyped.html.

#### Clone

When a java object is mapped to EO the underlying object is a clone with the same structure and leaf values.

    final AnObject anObject = new AnObject();

    anObject.setMyString("value1");

    final EoRoot rootMap = EoRoot.ofValue(CONFIG_MAPS, anObject);

    final AnObject cloned = (AnObject) rootMap.get();

    assertNotEquals(anObject, cloned);

    assertEquals(anObject.getMyString(), cloned.getMyString());

#### Transform

One can easily transform an object to another type, when the target object has the same fields. The following example  

creates a Map from AnObject:

    final AnObject anObject = new AnObject();

    anObject.setMyString("value2");

    final EoRoot rootMap = EoRoot.ofClass(CONFIG_MAPS, anObject, Map.class);

    final Map transformed = (Map) rootMap.get();

    assertEquals(anObject.getMyString(), transformed.get("myString"));

#### Non Mapped values

Every field key starting with underscore will not be mapped to the parent object.

    final String json = "{\"myString\":\"test\", \"_comment\":\"FieldNames with underscore will not set in parent object.\"}";

    final EoRoot root = EoRoot.ofClass(CONFIG_MAPS, json, AnObject.class);

    assertEquals("FieldNames with underscore will not set in parent object.", root.get("_comment"));

    assertEquals("{\n" +

            "  \"myString\": \"test\"\n" +

            "}", root.toJson(JSONSerializationType.STANDARD));

Interactive example: https://www.elasticobjects.org/examples/Comment.html.

## Calls (eo-calls)

### eo-calls Module

The [calls](eo-calls) module with a jar size of about 150 KB offers some basic calls also using configurations with a role permission concept for

files and directories

simple csv

or templates.

    

        org.fluentcodes.projects.elasticobjects

        eo-calls

        0.9.2

    

  


mvn repository



### eo-calls Examples



The call classes implementing the

  Call

interface offer functionality. A bunch of calls including file access or

templates you find in

  eo-calls.





 The following examples using

   SinusValueCall

are found in

  EOReadmeTest.



#### Java Example



The generic execute method has EO as input.

Here we set the field key "squareDegree" to 2.1 and directly call

   SinusValueCall.



        final Call call = new SinusValueCall();

        EoRoot root = EoRoot.ofValue(CONFIG_MAPS, new HashMap());

        EOInterfaceScalar child = root.set(2.1, "squareDegree");

        assertEquals(2.1, child.get());

        assertEquals(Double.valueOf(0.8632093666488737), call.execute(child));

#### JSON Example

This call could be also embedded in some arbitrary json using the [≡sourcePath](https://www.elasticobjects.org/config/FieldConfig/sourcePath) as input. The result will stored to the [≡targetPath](https://www.elasticobjects.org/config/FieldConfig/targetPath) "sinusValue".

        EoRoot root = EoRoot.ofValue(CONFIG_MAPS, "{\n" +

                "  \"(Double)squareDegree\":1,\n" +

                "  \"(SinusValueCall)sinusValue\": {\n" +

                "    \"sourcePath\": \"/squareDegree\"\n" +

                "  }\n" +

                "}");

        root.execute();

        assertEquals("{\n" +

                "  \"squareDegree\": 1.0,\n" +

                "  \"sinusValue\": 0.8414709848078965\n" +

                "}", root.toJson(JSONSerializationType.STANDARD));

Interactive example: https://www.elasticobjects.org/examples/SinusValueCall.html.

#### Template Example

This json will be interpreted in an arbitrary text file via template call with the "@{...}" pattern. Here the target _asString will return the result to the template instead of setting the target in json.

        EoRoot root = EoRoot.of(CONFIG_MAPS);

        String template = "START - @{\n" +

                "  \"(Double)source\":1,\n" +

                "  \"(SinusValueCall)_asString\": {\n" +

                "    \"sourcePath\": \"/source\"\n" +

                "  }\n" +

                "}. - END";

        Call call = new TemplateCall(template);

        assertEquals("START -0.8414709848078965 - END", call.execute(root));

Interactive example: https://www.elasticobjects.org/examples/SinusValueCallTemplate.html.

##### Other Template forms

Calls could be included in an attribute and command form. This will be demonstrated by the following examples:

* https://www.elasticobjects.org/examples/SinusValueCallCommandTemplate.html

* https://www.elasticobjects.org/examples/SinusValueCallAttributeTemplate.html

#### Files

http://localhost:8080/examples/FileCall.html

http://localhost:8080/examples/JsonCall.html

#### Templates

Interactive Examples: http://localhost:8080/examples/TemplateExamples.html

## Csv (eo-csv)

[eo-csv](eo-csv) offers calls and configurations for reading and writing csv files  using [OpenCsv](https://mvnrepository.com/artifact/com.opencsv/opencsv).

    

        org.fluentcodes.projects.elasticobjects

        eo-csv

        0.9.4

    



mvn repository



Interactive examples: http://localhost:8080/examples/ListCall.html

## Database (eo-db)

[eo-db](eo-db)

is experimental providing the execution of sql configurations as list or as query.

    

        org.fluentcodes.projects.elasticobjects

        eo-db

        0.9.4

    



mvn repository



Interactive examples: https://www.elasticobjects.org/examples/DbCall.html.

## Excel (eo-xlsx)

[eo-xlsx](eo-xlsx) offers calls and configurations for reading and writing xlsx files using [Apache POI](https://mvnrepository.com/artifact/org.apache.poi/poi).

    

        org.fluentcodes.projects.elasticobjects

        eo-xlsx

        0.9.4

    

Interactive examples: http://localhost:8080/examples/ExcelCall.html

## Other Modules

### elastic-objects-test

[elastic-objects-test](elastic-objects-test) provide tests for the [elastic-objects](elastic-objects) module.  The main package providing test helper and test objects to other modules.

Since it has just test purposes there is actual no package on [mvn central](https://mvnrepository.com/artifact/org.fluentcodes.projects.elasticobjects/).

### examples-springboot

[examples-springboot](example-springboot)

are the sources for the spring boot web example on

[http://www.elasticobjects.org](http://www.elasticobjects.org).

Since it has just demo purposes there is actual no package on [mvn central](https://mvnrepository.com/artifact/org.fluentcodes.projects.elasticobjects/).

## Background

### Elastic Objects



    Elastic Objects is a generic object wrapper skin

    with typed path methods to an java object skeleton.

    Typed objects are embedded in an untyped map structure.







Some code examples you will find in http://elasticobjects.org/eo/EO.html.



### Model Configurations

For the access to the embedded java objects EO

    is provided by preloaded model configurations in JSON.



### Call Types

A special

 Call

 bean with a

    generic execution method offers functionality. Its has the following important fields: 




    


≡sourcePath

 for the location of the input

    


≡targetPath

 for storing the output

    


≡condition







## Conclusion

The project has now version 0.9.4.

As a tool for creating and manipulating java objects it offers a lot of benefits.

For productive use in a flexible microservice architecture it's good enough for a proof of concept.

## Links

* https://tech.signavio.com/2017/json-type-information

* https://www.json.org/json-en.html

* https://de.wikipedia.org/wiki/JSON-LD

* http://restcookbook.com/Mediatypes/json/

* https://gkulshrestha.wordpress.com/2013/11/16/embedding-type-information-in-json-posted-to-web-api/

* https://www.newtonsoft.com/json/help/html/T_Newtonsoft_Json_TypeNameHandling.htm

* https://de.wikipedia.org/wiki/JavaScript_Object_Notation

* http://jsonp.eu/

* https://github.com/json-path/JsonPath