v6: list, deleteAll, exists methods for collections namespace

src/it/java/io/weaviate/integration/CollectionsITest.java

@@ -86,4 +86,32 @@ public void testCrossReferences() throws IOException {
               .containsOnly(nsOnlineStores, nsMarkets);
         });
   }
+
+  @Test
+  public void testListDeleteAll() throws IOException {
+    var nsA = ns("A");
+    var nsB = ns("B");
+    var nsC = ns("C");
+
+    client.collections.create(nsA);
+    client.collections.create(nsB);
+    client.collections.create(nsC);
+
+    Assertions.assertThat(client.collections.exists(nsA)).isTrue();
+    Assertions.assertThat(client.collections.exists(nsB)).isTrue();
+    Assertions.assertThat(client.collections.exists(nsC)).isTrue();
+    Assertions.assertThat(client.collections.exists(ns("X"))).isFalse();
+
+    var all = client.collections.list();
+    Assertions.assertThat(all)
+        .hasSizeGreaterThanOrEqualTo(3)
+        .extracting(WeaviateCollection::name)
+        .contains(nsA, nsB, nsC);
+
+    client.collections.deleteAll();
+
+    all = client.collections.list();
+    Assertions.assertThat(all.isEmpty());
+
+  }
 }

src/main/java/io/weaviate/client6/v1/api/collections/ListCollectionRequest.java

@@ -0,0 +1,21 @@
+package io.weaviate.client6.v1.api.collections;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.hc.core5.http.HttpStatus;
+
+import com.google.gson.reflect.TypeToken;
+
+import io.weaviate.client6.v1.internal.json.JSON;
+import io.weaviate.client6.v1.internal.rest.Endpoint;
+
+public record ListCollectionRequest() {
+  public static final Endpoint<ListCollectionRequest, List<WeaviateCollection>> _ENDPOINT = Endpoint.of(
+      request -> "GET",
+      request -> "/schema",
+      (gson, request) -> null,
+      request -> Collections.emptyMap(),
+      code -> code != HttpStatus.SC_SUCCESS,
+      (gson, response) -> JSON.deserialize(response, ListCollectionResponse.class).collections());
+}

src/main/java/io/weaviate/client6/v1/api/collections/ListCollectionResponse.java

@@ -0,0 +1,8 @@
+package io.weaviate.client6.v1.api.collections;
+
+import java.util.List;
+
+import com.google.gson.annotations.SerializedName;
+
+public record ListCollectionResponse(@SerializedName("classes") List<WeaviateCollection> collections) {
+}

src/main/java/io/weaviate/client6/v1/api/collections/WeaviateCollectionsClient.java

@@ -1,6 +1,7 @@
 package io.weaviate.client6.v1.api.collections;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Function;
@@ -41,7 +42,21 @@ public Optional<WeaviateCollection> getConfig(String name) throws IOException {
     return this.restTransport.performRequest(new GetConfigRequest(name), GetConfigRequest._ENDPOINT);
   }
 
+  public List<WeaviateCollection> list() throws IOException {
+    return this.restTransport.performRequest(new ListCollectionRequest(), ListCollectionRequest._ENDPOINT);
+  }
+
   public void delete(String name) throws IOException {
     this.restTransport.performRequest(new DeleteCollectionRequest(name), DeleteCollectionRequest._ENDPOINT);
   }
+
+  public void deleteAll() throws IOException {
+    for (var collection : list()) {
+      delete(collection.name());
+    }
+  }
+
+  public boolean exists(String name) throws IOException {
+    return getConfig(name).isPresent();
+  }
 }