[Feature] Add dimension() in EmbeddingModel

[Martin7-1]

Issue

#1080

Change

Add dimension() method in EmbeddingModel. Using an AbstractEmbeddingModel to implement EmbeddingModel and a common dimension() method like below:

    @Override
    public int dimension() {
        if (dimension != null) {
            return dimension;
        }

        return dimensionMap().compute(modelName(), (key, value) -> {
            this.dimension = Optional.ofNullable(value).orElse(embed("test").content().dimension());
            return dimension;
        });
    }

Now, existing {NameOfIntegration}EmbeddingModel just need to override dimensionMap() method to contains known embedding model dimension and modelName() method to get embedding model name.

General checklist

• There are no breaking changes
• I have added unit and integration tests for my change
• I have manually run all the unit and integration tests in the module I have added/changed, and they are all green
• I have manually run all the unit and integration tests in the core and main modules, and they are all green

• I have added/updated the documentation
• I have added an example in the examples repo (only for "big" features)

Checklist for adding new model integration

• I have added my new module in the BOM

Checklist for adding new embedding store integration

• I have added a {NameOfIntegration}EmbeddingStoreIT that extends from either EmbeddingStoreIT or EmbeddingStoreWithFilteringIT
• I have added my new module in the BOM

Checklist for changing existing embedding store integration

• I have manually verified that the {NameOfIntegration}EmbeddingStore works correctly with the data persisted using the latest released version of LangChain4j

[langchain4j]

@Martin7-1 thank you!

[langchain4j]

@Martin7-1 I like this new solution much more, thank you!

Just a few minor things and we can merge!

[Martin7-1]

The CI failed maybe because the main branch's commit. @langchain4j

[langchain4j]

@Martin7-1 good job, thank you!

[langchain4j]

@Martin7-1 could you please also update embedding models in https://github.com/langchain4j/langchain4j-embeddings ?

[Martin7-1]

@Martin7-1 could you please also update embedding models in https://github.com/langchain4j/langchain4j-embeddings ?

Sure!