Interface UpdateDSLCompleter

All Superinterfaces:
Function<UpdateDSL<UpdateModel>, Buildable<UpdateModel>>
Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface UpdateDSLCompleter extends Function<UpdateDSL<UpdateModel>, Buildable<UpdateModel>>
Represents a function that can be used to create a general update method. When using this function, you can create a method that does not require a user to call the build() and render() methods - making client code look a bit cleaner.

This function is intended to be used in conjunction in the utility method like MyBatis3Utils.update(ToIntFunction, SqlTable, UpdateDSLCompleter)

For example, you can create mapper interface methods like this: 

@UpdateProvider(type=SqlProviderAdapter.class, method="update")
int update(UpdateStatementProvider updateStatement);

default int update(UpdateDSLCompleter completer) {
       return MyBatis3Utils.update(this::update, person, completer);
}

And then call the simplified default method like this: 

int rows = mapper.update(c ->
               c.set(firstName).equalTo("Fred")
               .where(id, isEqualTo(100))
           );

You can implement an "update all" simply by omitting a where clause: 

int rows = mapper.update(c ->
               c.set(firstName).equalTo("Fred")
           );

You could also implement a helper method that would set fields based on values of a record. For example, the following method would set all fields of a row based on whether the values are null: 

static UpdateDSL<UpdateModel> updateSelectiveColumns(PersonRecord record,
        UpdateDSL<UpdateModel> dsl) {
    return dsl.set(id).equalToWhenPresent(record::getId)
            .set(firstName).equalToWhenPresent(record::getFirstName)
            .set(lastName).equalToWhenPresent(record::getLastName)
            .set(birthDate).equalToWhenPresent(record::getBirthDate)
            .set(employed).equalToWhenPresent(record::getEmployed)
            .set(occupation).equalToWhenPresent(record::getOccupation);
}

The helper method could be used like this: 

rows = mapper.update(c ->
       PersonMapper.updateSelectiveColumns(record, c)
       .where(id, isLessThan(100)));

In this way, you could mimic the function of the old style "updateByExampleSelective" methods from MyBatis Generator.

Author:
Jeff Butler