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https://github.com/greendelta/olca-ilcd


https://github.com/greendelta/olca-ilcd

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README 

        
# openLCA ILCD API



This is a Java library for reading and writing data sets in the

[ILCD data format](https://eplca.jrc.ec.europa.eu/LCDN/developerILCDDataFormat.xhtml).

It was originally part of the [openLCA modules](https://github.com/GreenDelta/olca-modules)

but was moved to a separate repository since version 2.0.0.



## Usage



Add this dependency to your project:



```xml



  org.openlca

  olca-ilcd

  3.0.0



```



## New in version 3



### Fluent builder API



The ILCD format defines deeply structured data types. With a fluent API we made it easier to create such structures. Version 2 was based on public properties, you could use them like this (in the most compact form):



```java

var flow = new Flow();

flow.flowInfo = new FlowInformation();

flow.flowInfo.dataSetInfo = new DataSetInfo();

flow.flowInfo.dataSetInfo.uuid = "123abc...";

flow.flowInfo.dataSetInfo.flowName = new FlowName();

flow.flowInfo.dataSetInfo.flowName.baseName.add(

  LangString.of("carbon dioxide", "en"));

```



In version 3, you can write the example above like this:



```java

var flow = new Flow()

  .withFlowInfo()

  .withDataSetInfo()

  .withUUID("123abc...")

  .withFlowName()

  .withBaseName()

  .add(LangString.of("carbon dioxide", "en"));

```



The `with{Field}()` methods will create inner data structures if needed and return them directly. The `with{Field}(value)` methods will set the value of the field and return the instance on which this method was called. For example, `withDataSetInfo()` creates a `DataSetInfo` and binds it to `FlowInfo` if it was not created yet, `withUUID("123...")` sets the value of the `UUID` field and returns the `DataSetInfo` instance, on which then the base name list is created if needed.



### Everything lazy



In version 2, collection fields like lists and maps were all eagerly created and bound to `final` fields, e.g.:



```java

public class Process {

  // ...

  public final List exchanges = new ArrayList<>();



}

```



Now in version 3, they are all `private` and `null` initially:



```java

public class Process {

  // ...

  private List exchanges = null;



  // ...

  public List getExchanges() {

    return exchanges != null

      ? exchanges

      : Collections.emptyList();

  }

}

```



As you can see in the example, the accessor will return an empty list if they are `null`, so it is safe to directly query the returned list. However, you should **never** modify a collection that is returned with a `get*` accessor, use the `with*` builder for this, e.g.:



```java

process.withExchanges().add(

  new Exchange()

    .withFlow(flow)

    .withResultingAmount(42));

```



Collections as any other field can be now simply set to `null` to clear them:



```java

process

  .withProcessInfo(null)

  .withExchanges(null);

```



For querying deeply nested fields we still have the `null` safe utility methods like in version 2. Remember to always check for `null` when using the `get*` methods for non-collection fields:



```java

var pub = Processes.getPublication(process);

if (pub != null) {

  println("Version is: " + pub.getVersion());

}

```



Because of this "laziness" we could remove some wrapper classes from the API and get rid of arrays. Also, the API is  more memory efficient now.



### The `Xml` utility class



Reading and writing ILCD datasets from and to files, streams, strings, byte arrays, etc. is easier with the `Xml` utility class:



```java

var flow = new Flow();

flow.withFlowInfo()

  .withDataSetInfo()

  .withUUID("123abc...")

  .withFlowName()

  .withBaseName()

  .add(LangString.of("carbon dioxide", "en"));



println(Xml.toString(flow));

```



This will print:



```xml



    

        

            123abc...

            

                carbon dioxide

            

        

    



```