Description Rainer Menke 2011-03-08 07:17:14 EST

Build Identifier: I20100608-0911

Wrote a simple ecore-Model for property-Files, and made a simple test whether the definition and usage of variables is possible. I used Acceleo 3.1.0M5 for this. In the template I store for some reasons values temporary to access them for a later usage. If I use the java service with a static parameter, it seems like this java service call is optimized to be executed just one time.

First write a simple template, where two java services are used, one is for setting, the other for reading internal values:
[comment encoding = UTF-8 /]
[module generate('properties')/]

[query public setGlobalProperty(property: String , value: String) : Boolean = invoke('org.eclipse.acceleo.module.sample.services.GlobalProperties','setProperty(java.lang.String, java.lang.String)',Sequence{property,value})/]
[query public getGlobalProperty(property: String) : String = invoke('org.eclipse.acceleo.module.sample.services.GlobalProperties','getProperty(java.lang.String)',Sequence{property})/]

[template public generate(p : PropertiesType)]
	
[file ('props.txt', false, 'UTF-8')]
	[for ( pp : PropertyType | p.property ) ]
		[setGlobalProperty('lastProperty',pp.name)/]
		[setGlobalProperty(pp.name, pp.value)/]
Save of '[pp.name/]' with '[pp.value/]'
		[let last : String = pp.name ]
1.) read '[last/]' with '[getGlobalProperty(last)/]'
		[/let]
		[let last : String = getGlobalProperty('lastProperty') ]
2.) read '[last/]' with '[getGlobalProperty(last)/]'
		[/let]
	[/for]
[/file]
	
[/template]

2.) Implement the java services:
public class GlobalProperties {
	private static Properties properties = new Properties();
	public static String getProperty( String property ) {
		String value = properties.getProperty( property );
		System.out.println( "getProperty: property '" + property + "' value '" + value + "'" );
		return value;
	}
	public static void setProperty(String property,String value) {
		String _value = properties.getProperty( property );
		System.out.println( "setProperty: property '" + property + "' value '" + value + "' replacing '" + _value + "'" );
		properties.setProperty( property, value );
		_value = properties.getProperty( property );
		System.out.println( "setProperty: property '" + property + "' value '" + _value + "'" );
	}
}

Under the console you see:

setProperty: property 'lastProperty' value 'a' replacing 'null'
setProperty: property 'lastProperty' value 'a'
setProperty: property 'a' value 'b' replacing 'null'
setProperty: property 'a' value 'b'
getProperty: property 'a' value 'b'
getProperty: property 'lastProperty' value 'a'
setProperty: property 'lastProperty' value 'b' replacing 'a'
setProperty: property 'lastProperty' value 'b'
setProperty: property 'b' value 'c' replacing 'null'
setProperty: property 'b' value 'c'
getProperty: property 'b' value 'c'
setProperty: property 'lastProperty' value 'd' replacing 'b'
setProperty: property 'lastProperty' value 'd'
setProperty: property 'd' value 'e' replacing 'null'
setProperty: property 'd' value 'e'
getProperty: property 'd' value 'e'

As result the following is produced:

Save of 'a' with 'b'
1.) read 'a' with 'b'
2.) read 'a' with 'b'
		
Save of 'b' with 'c'
1.) read 'b' with 'c'
2.) read 'a' with 'b'
		
		
Save of 'd' with 'e'
1.) read 'd' with 'e'
2.) read 'a' with 'b'


Reproducible: Always

Steps to Reproduce:
1.) Take some input model (independent)
2.) Build two java services, one for storing, one for accessing 
3.) Write a template where the values of some variables are exchanged during the generation phase

See the details for implementation ;-)