supabase-java

About

This project establishes a Java based client to interact with a Supabase database. Currently, Supabase does not offer a Java based library for its database, so I tried to make one instead.

Supabase Java Native

A Supabase client library written in vanilla Java. It contains minimal dependencies to external libraries and makes use of Java's HttpClient to interact with the Supabase database API.

Supabase Java Spring

A Supabase client that is native to the Spring 3 framework. It uses WebClient under the hood to interact with the Supabase database API.

Quick Start

Importing Maven Dependency

If you want to use the native Java client then include the following dependency in your POM file:

<dependency>
    <groupId>com.skhanal5</groupId>
    <artifactId>supabase-java-native</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

For the Spring based client, use this dependency instead in your POM file:

<dependency>
  <groupId>com.skhanal5</groupId>
  <artifactId>supabase-java-spring</artifactId>
  <version>1.0-SNAPSHOT</version>
</dependency>

Client Initialization

The easiest way of initializing a SupabaseClient is passing in the base URL of your Supabase database from your dashboard along with the service key.

    var client = SupabaseClient.newInstance("https://abcdefghijklmnop.supabase.co", SERVICE_KEY);

Building a Query

From there, you can invoke an operation on your database by building a query. Each operation has its own corresponding query object.

SelectQuery

To select a column in the table, you can use the SelectQuery. For example:

    var query = new SelectQuery
        .SelectQueryBuilder()
        .from("doctors")
        .select("*")
        .build();

This query is the SQL equivalent of selecting all fields from the doctors table.

InsertQuery

To insert a row or multiple rows into the table, you can use the InsertQuery.

    var query = new InsertQuery
        .InsertQueryBuilder()
        .from("doctors")
        .insert(Map.of("full_name", "John Doe")
        .select()
        .build();

Note: Executing this query will return null if you do not invoke select(). If select is invoked, it will return the new row/rows inserted in the table.

UpdateQuery

If you want to update a specific row, you can use the UpdateQuery along with a Filter. For more information on filtering, view the section on using Filters.

    var filter = new Filter
        .FilterBuilder()
        .equals("full_name", "John Doe")
        .build();

    var query = new UpdateQuery
        .UpdateQueryBuilder()
        .from("doctors")
        .update(Map.of("full_name", "John Smith")
        .filter(filter)
        .select()
        .build();

Note: Executing this query will return null if you do not invoke select(). If select is invoked, it will return the updated row in the table.

DeleteQuery

If you want to delete a specific row (or rows), you can use the DeleteQuery along with a Filter.

    var filter = new Filter
        .FilterBuilder()
        .equals("full_name", "John")
        .build();

    var query = new DeleteQuery
        .DeleteQueryBuilder()
        .from("doctors")
        .delete()
        .filter(filter)
        .select()
        .build();

Note: If you do not invoke the select() method, you will not get a response back from executing this query. Invoking it returns the deleted row(s).

Executing a Query

Lastly, you can execute the query and invoke the Supabase database API by using executeQuery(Query query, Class<T> responseClass). The responseClass parameter is used to deserialize the JSON response into the corresponding POJO.

If we wanted to execute the SearchQuery from above, we would do this:

    var response = client.executeSelect(query, String.class);
    System.out.println(response);
    //output: [{"id":"12345-6789","foo":"bar"}]

Aside: Supabase Responses

As you can see, the underlying Supabase database produces a list of objects where each object corresponds to a row of your table. The key-value pairs inside of that object map to the values under each column defined in your table.

So the response above, would correspond to the table below:

	id (varchar)	foo (varchar)
1	12345-6789	bar

Filters

You can include a Filter in your query to refine your search. Here are the following filters that are supported:

equals(String column, String value) Match only rows where column is equal to value.

notEquals(String column, String value) Match only rows where column is not equal to value.

greaterThan(String column, int value) Match only rows where column is greater than value.

greaterThanOrEquals(String column, int value) Match only rows where column is greater than or equal to value.

lessThan(String column, int value) Match only rows where column is less than value.

lessThanOrEquals(String column, int value) Match only rows where column is less than or equal to value.

in(String column, List<String> values Match only rows where column contains every element appearing in value.

like(String column, String pattern) Match only rows where column matches pattern case-sensitively.

ilike(String column, String pattern) Match only rows where column matches pattern case-insensitively.

Query Filter Usage

Here is how you can use the FilterBuilder to build a Filter:

    var filter = new Filter.FilterBuilder()
            .equals("specialty", "Internal Medicine")
            .greaterThan("years_of_experience", 2)
            .greaterThanOrEquals("years_of_experience", 5)
            .lessThan("distance", 2)
            .lessThanOrEquals("rating", 2)
            .in("state",List.of("Virginia", "Maryland"))
            .like("full_name", "%John Doe%")
            .ilike("phone_number", "%fakenumber%")
            .notEquals("full_name", "null")
            .build();

Note: Filters are supported for SearchQuery, UpdateQuery, and DeleteQuery

    var query = new SearchQuery.SearchQueryBuilder()
            .from("doctors")
            .select("*")
            .filter(filter)