Testing JPA-based applications - JUnit in Action - page 376

E

public static long db_id(String className) {
long id;
if ( IDS.containsKey(className) ) {
id = IDS.get(className);
} else {
id = INITIAL_ID;
}
return id;
}

F

public static void setId(String className, long newId) {
if ( ! IDS.containsKey(className) ) {
IDS.put(className, newId);
}
}

G

public static void resetIds() {
IDS.clear();
}

H

public static long getId(Class<?> clazz) {
return db_id(clazz.getSimpleName());
}

}
This defines the value returned by the ID function when no ID was set for a given class.
This initializes the map of static methods that define EL functions. To facilitate the
mapping, these methods starts with db_ .
resolveFunction() is part of the EL API and is used to map an EL function (such as
db:id ) to a Java method ( db_id() , in this case). It returns the method defined at C .
This is the id function properly speaking, which returns either the initial ID or the
value present in the ID 's map.
Our custom Hibernate listener calls this method every time a new entity is generated,
but only the first value is saved in the ID 's map; the other values are calculated by the
dataset, using this base ID when necessary (such as ${db:id('Telephone')+1} , if the
dataset has two telephone rows). Notice that this mechanism assumes ID s are gener-
ated in sequence, which is true most of the time, but not always. If that doesn't apply
in your case (for instance, if you're using a generation strategy based on UUID s),
you'll need a different (and more complex) approach to represent multiple ID s, like
using a sequence parameter in the id function: ${db:id('Telephone',1)} would
return the first generated ID , ${db:id(´Telephone',2)} would return the second,
and so on. Then instead of keeping a single ID in the map, you'd keep a list of the gen-
erated ID s for each class.
The ID map must be reset before each method, so load methods always start with id=1
(or whatever value is defined at B ).
This is the helper method used by test cases that need to know the base ID for a
given class.

B
C

D

E

F

G

H