Java
Installation and setup​
To get the latest stable version of the Java client library, add this dependency to your project:
<dependency>
<groupId>technology.semi.weaviate</groupId>
<artifactId>client</artifactId>
<version>3.2.0</version>
</dependency>
This API client is compatible with Java 8 and beyond.
You can use the client in your project as follows:
import technology.semi.weaviate.client.Config;
import technology.semi.weaviate.client.WeaviateClient;
import technology.semi.weaviate.client.base.Result;
import technology.semi.weaviate.client.v1.misc.model.Meta;
public class App {
public static void main(String[] args) {
Config config = new Config("http", "localhost:8080");
WeaviateClient client = new WeaviateClient(config);
Result<Meta> meta = client.misc().metaGetter().run();
if (meta.getError() == null) {
System.out.printf("meta.hostname: %s\n", meta.getResult().getHostname());
System.out.printf("meta.version: %s\n", meta.getResult().getVersion());
System.out.printf("meta.modules: %s\n", meta.getResult().getModules());
} else {
System.out.printf("Error: %s\n", meta.getError().getMessages());
}
}
}
Authentication​
You can pass authentication credentials in a header to the client, which is added to the initialization of the client in your Java project:
import technology.semi.weaviate.client.Config;
import technology.semi.weaviate.client.WeaviateClient;
import technology.semi.weaviate.client.base.Result;
import technology.semi.weaviate.client.v1.misc.model.Meta;
public class App {
public static void main(String[] args) {
Map<String, String> headers = new HashMap<String, String>() { {
put("Authorization", "Bearer <put your token here>");
} };
Config config = new Config("http", "localhost:8080", headers);
WeaviateClient client = new WeaviateClient(config);
Result<Meta> meta = client.misc().metaGetter().run();
}
}
References​
All RESTful endpoints and GraphQL functions references covered by the Java client, and explained on those reference pages in the code blocks.
Design​
Builder pattern​
The Java client functions are designed with a 'Builder pattern'. A pattern is used to build complex query objects. This means that a function (for example to retrieve data from Weaviate with a request similar to a RESTful GET request, or a more complex GraphQL query) is built with single objects to reduce complexity. Some builder objects are optional, others are required to perform specific functions. All is documented on the RESTful API reference pages and the GraphQL reference pages.
The code snippet above shows a simple query similar to RESTful GET /v1/meta. The client is initiated by requiring the package and connecting to the running instance. Then, a query is constructed by using the .metaGetter() on .misc(). The query will be sent with the .run() function, this object is thus required for every function you want to build and execute.
Migration Guides​
From 2.4.0 to 3.0.0​
Removed @Deprecated method Aggregate::withFields(Fields fields)​
Before:
// import technology.semi.weaviate.client.v1.graphql.query.fields.Field;
// import technology.semi.weaviate.client.v1.graphql.query.fields.Fields;
Fields fields = Fields.builder().fields(new Field[]{name, description}).build();
client.graphQL().aggregate().withFields(fields)...
After:
client.graphQL().aggregate().withFields(name, description)...
Removed @Deprecated method Get::withFields(Fields fields)​
Before:
// import technology.semi.weaviate.client.v1.graphql.query.fields.Field;
// import technology.semi.weaviate.client.v1.graphql.query.fields.Fields;
Fields fields = Fields.builder().fields(new Field[]{name, description}).build();
client.graphQL().get().withFields(fields)...
After:
client.graphQL().get().withFields(name, description)...
Removed @Deprecated method Get::withNearVector(Float[] vector)​
Before:
client.graphQL().get().withNearVector(new Float[]{ 0f, 1f, 0.8f })...
After:
// import technology.semi.weaviate.client.v1.graphql.query.argument.NearVectorArgument;
NearVectorArgument nearVector = NearVectorArgument.builder().vector(new Float[]{ 0f, 1f, 0.8f }).certainty(0.8f).build();
client.graphQL().get().withNearVector(nearVector)...
All where filters use the same implementation​
With batch delete feature, unified filters.WhereFilter implementation is introduced, which replaces classifications.WhereFilter, graphql.query.argument.WhereArgument and graphql.query.argument.WhereFilter.
GraphQL​
Before:
// import technology.semi.weaviate.client.v1.graphql.query.argument.GeoCoordinatesParameter;
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereArgument;
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereOperator;
GeoCoordinatesParameter geo = GeoCoordinatesParameter.builder()
.latitude(50.51f)
.longitude(0.11f)
.maxDistance(3000f)
.build();
WhereArgument where = WhereArgument.builder()
.valueGeoRange(geo)
.operator(WhereOperator.WithinGeoRange)
.path(new String[]{ "add "})
.build();
client.graphQL().aggregate().withWhere(where)...
After:
// import technology.semi.weaviate.client.v1.filters.Operator;
// import technology.semi.weaviate.client.v1.filters.WhereFilter;
WhereFilter where = WhereFilter.builder()
.valueGeoRange(WhereFilter.GeoRange.builder()
.geoCoordinates(WhereFilter.GeoCoordinates.builder()
.latitude(50.51f)
.longitude(0.11f)
.build()
)
.distance(WhereFilter.GeoDistance.builder()
.max(3000f)
.build()
)
.build()
)
.operator(Operator.WithinGeoRange)
.path(new String[]{ "add" })
.build();
client.graphQL().aggregate().withWhere(where)...
Before:
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereArgument;
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereOperator;
WhereArgument where = WhereArgument.builder()
.valueString("txt")
.operator(WhereOperator.Equal)
.path(new String[]{ "add" })
.build();
client.graphQL().aggregate().withWhere(where)...
After:
// import technology.semi.weaviate.client.v1.filters.Operator;
// import technology.semi.weaviate.client.v1.filters.WhereFilter;
WhereFilter where = WhereFilter.builder()
.valueString("txt")
.operator(Operator.Equal)
.path(new String[]{ "add" })
.build();
client.graphQL().aggregate().withWhere(where)...
Before:
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereArgument;
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereFilter;
// import technology.semi.weaviate.client.v1.graphql.query.argument.WhereOperator;
WhereArgument where = WhereArgument.builder()
.operands(new WhereFilter[]{
WhereFilter.builder()
.valueInt(10)
.path(new String[]{ "wordCount" })
.operator(WhereOperator.LessThanEqual)
.build(),
WhereFilter.builder()
.valueString("word")
.path(new String[]{ "word" })
.operator(WhereOperator.LessThan)
.build()
})
.operator(WhereOperator.And)
.build();
client.graphQL().aggregate().withWhere(where)...
After:
// import technology.semi.weaviate.client.v1.filters.Operator;
// import technology.semi.weaviate.client.v1.filters.WhereFilter;
WhereFilter where = WhereFilter.builder()
.operands(new WhereFilter[]{
WhereFilter.builder()
.valueInt(10)
.path(new String[]{ "wordCount" })
.operator(Operator.LessThanEqual)
.build(),
WhereFilter.builder()
.valueString("word")
.path(new String[]{ "word" })
.operator(Operator.LessThan)
.build(),
})
.operator(Operator.And)
.build();
client.graphQL().aggregate().withWhere(where)...
Classification​
Before:
// import technology.semi.weaviate.client.v1.classifications.model.GeoCoordinates;
// import technology.semi.weaviate.client.v1.classifications.model.Operator;
// import technology.semi.weaviate.client.v1.classifications.model.WhereFilter;
// import technology.semi.weaviate.client.v1.classifications.model.WhereFilterGeoRange;
// import technology.semi.weaviate.client.v1.classifications.model.WhereFilterGeoRangeDistance;
WhereFilter where = WhereFilter.builder()
.valueGeoRange(WhereFilterGeoRange.builder()
.geoCoordinates(GeoCoordinates.builder()
.latitude(50.51f)
.longitude(0.11f)
.build())
.distance(WhereFilterGeoRangeDistance.builder()
.max(3000d)
.build())
.build())
.operator(Operator.WithinGeoRange)
.path(new String[]{ "geo" })
.build();
client.classifications().scheduler().withTrainingSetWhereFilter(where)...
After:
// import technology.semi.weaviate.client.v1.filters.Operator;
// import technology.semi.weaviate.client.v1.filters.WhereFilter;
WhereFilter where = WhereFilter.builder()
.valueGeoRange(WhereFilter.GeoRange.builder()
.geoCoordinates(WhereFilter.GeoCoordinates.builder()
.latitude(50.51f)
.longitude(0.11f)
.build())
.distance(WhereFilter.GeoDistance.builder()
.max(3000f)
.build())
.build())
.operator(Operator.WithinGeoRange)
.path(new String[]{ "geo" })
.build();
client.classifications().scheduler().withTrainingSetWhereFilter(where)...
Change logs​
Check the change logs on GitHub for updates on the latest Java client changes.
More Resources​
If you can't find the answer to your question here, please look at the:
- Frequently Asked Questions. Or,
- Knowledge base of old issues. Or,
- For questions: Stackoverflow. Or,
- For issues: Github. Or,
- Ask your question in the Slack channel: Slack.