docs: Expand hello world snippet to show how to access specific cells (#516)

* samples: Expand hello world snippet to show how to access specific cells by family & qualifier * samples: Expand hello world snippet to show how to access specific cells by family & qualifier

Author: dmitry-fa

samples/snippets/src/main/java/com/m/examples/bigtable/HelloWorld.java

@@ -12,7 +12,7 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
-*/
+ */
 
 package com.m.examples.bigtable;
 
@@ -29,6 +29,8 @@
 import com.google.cloud.bigtable.data.v2.models.RowCell;
 import com.google.cloud.bigtable.data.v2.models.RowMutation;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 // [END bigtable_hw_imports_veneer]
 
@@ -48,7 +50,8 @@
 public class HelloWorld {
 
  private static final String COLUMN_FAMILY = "cf1";
- private static final String COLUMN_QUALIFIER = "greeting";
+ private static final String COLUMN_QUALIFIER_GREETING = "greeting";
+ private static final String COLUMN_QUALIFIER_NAME = "name";
  private static final String ROW_KEY_PREFIX = "rowKey";
  private final String tableId;
  private final BigtableDataClient dataClient;
@@ -94,8 +97,13 @@ public void run() throws Exception {
  createTable();
  writeToTable();
  readSingleRow();
+ readSpecificCells();
  readTable();
  deleteTable();
+ close();
+ }
+
+ public void close() {
  dataClient.close();
  adminClient.close();
  }
@@ -119,13 +127,15 @@ public void writeToTable() {
  // [START bigtable_hw_write_rows_veneer]
  try {
  System.out.println("\nWriting some greetings to the table");
- String[] greetings = {"Hello World!", "Hello Bigtable!", "Hello Java!"};
- for (int i = 0; i < greetings.length; i++) {
+ String[] names = {"World", "Bigtable", "Java"};
+ for (int i = 0; i < names.length; i++) {
+ String greeting = "Hello " + names[i] + "!";
  RowMutation rowMutation =
  RowMutation.create(tableId, ROW_KEY_PREFIX + i)
- .setCell(COLUMN_FAMILY, COLUMN_QUALIFIER, greetings[i]);
+ .setCell(COLUMN_FAMILY, COLUMN_QUALIFIER_NAME, names[i])
+ .setCell(COLUMN_FAMILY, COLUMN_QUALIFIER_GREETING, greeting);
  dataClient.mutateRow(rowMutation);
- System.out.println(greetings[i]);
+ System.out.println(greeting);
  }
  } catch (NotFoundException e) {
  System.err.println("Failed to write to non-existent table: " + e.getMessage());
@@ -134,7 +144,7 @@ public void writeToTable() {
  }
 
  /** Demonstrates how to read a single row from a table. */
- public void readSingleRow() {
+ public Row readSingleRow() {
  // [START bigtable_hw_get_by_key_veneer]
  try {
  System.out.println("\nReading a single row by row key");
@@ -145,29 +155,56 @@ public void readSingleRow() {
  "Family: %s Qualifier: %s Value: %s%n",
  cell.getFamily(), cell.getQualifier().toStringUtf8(), cell.getValue().toStringUtf8());
  }
+ return row;
+ } catch (NotFoundException e) {
+ System.err.println("Failed to read from a non-existent table: " + e.getMessage());
+ return null;
+ }
+ // [END bigtable_hw_get_by_key_veneer]
+ }
+
+ /** Demonstrates how to access specific cells by family and qualifier. */
+ public List<RowCell> readSpecificCells() {
+ // [START bigtable_hw_get_by_key_veneer]
+ try {
+ System.out.println("\nReading specific cells by family and qualifier");
+ Row row = dataClient.readRow(tableId, ROW_KEY_PREFIX + 0);
+ System.out.println("Row: " + row.getKey().toStringUtf8());
+ List<RowCell> cells = row.getCells(COLUMN_FAMILY, COLUMN_QUALIFIER_NAME);
+ for (RowCell cell : cells) {
+ System.out.printf(
+ "Family: %s Qualifier: %s Value: %s%n",
+ cell.getFamily(), cell.getQualifier().toStringUtf8(), cell.getValue().toStringUtf8());
+ }
+ return cells;
  } catch (NotFoundException e) {
  System.err.println("Failed to read from a non-existent table: " + e.getMessage());
+ return null;
  }
  // [END bigtable_hw_get_by_key_veneer]
  }
 
  /** Demonstrates how to read an entire table. */
- public void readTable() {
+ public List<Row> readTable() {
  // [START bigtable_hw_scan_all_veneer]
  try {
  System.out.println("\nReading the entire table");
  Query query = Query.create(tableId);
  ServerStream<Row> rowStream = dataClient.readRows(query);
+ List<Row> tableRows = new ArrayList<>();
  for (Row r : rowStream) {
  System.out.println("Row Key: " + r.getKey().toStringUtf8());
+ tableRows.add(r);
  for (RowCell cell : r.getCells()) {
  System.out.printf(
  "Family: %s Qualifier: %s Value: %s%n",
  cell.getFamily(), cell.getQualifier().toStringUtf8(), cell.getValue().toStringUtf8());
  }
  }
+ return tableRows;
  } catch (NotFoundException e) {
  System.err.println("Failed to read a non-existent table: " + e.getMessage());
+ return null;
  }
  // [END bigtable_hw_scan_all_veneer]
  }

samples/snippets/src/test/java/com/m/examples/bigtable/HelloWorldTest.java

@@ -12,27 +12,27 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
-*/
+ */
 
 package com.m.examples.bigtable;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 import com.google.cloud.bigtable.admin.v2.BigtableTableAdminClient;
 import com.google.cloud.bigtable.admin.v2.BigtableTableAdminSettings;
 import com.google.cloud.bigtable.admin.v2.models.CreateTableRequest;
 import com.google.cloud.bigtable.data.v2.BigtableDataClient;
 import com.google.cloud.bigtable.data.v2.BigtableDataSettings;
-import com.google.cloud.bigtable.data.v2.models.Row;
 import java.io.IOException;
 import java.util.Random;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import org.junit.After;
 import org.junit.AfterClass;
-import org.junit.AssumptionViolatedException;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -86,10 +86,11 @@ public void setup() throws IOException {
  }
 
  @After
- public void after() {
+ public void teardown() {
  if (adminClient.exists(tableId)) {
  adminClient.deleteTable(tableId);
  }
+ helloWorld.close();
  }
 
  @Test
@@ -103,18 +104,26 @@ public void testCreateAndDeleteTable() throws IOException {
  // Deletes a table.
  testHelloWorld.deleteTable();
  assertTrue(!adminClient.exists(testTable));
+ testHelloWorld.close();
  }
 
  @Test
  public void testWriteToTable() {
  // Writes to a table.
+ assertNull(dataClient.readRow(tableId, "rowKey0"));
  helloWorld.writeToTable();
- Row row = dataClient.readRow(tableId, "rowKey0");
- assertNotNull(row);
+ assertNotNull(dataClient.readRow(tableId, "rowKey0"));
  }
 
- // TODO: add test for helloWorld.readSingleRow()
- // TODO: add test for helloWorld.readTable()
+ @Test
+ public void testReads() {
+ assertEquals(0, helloWorld.readTable().size());
+ helloWorld.writeToTable();
+
+ assertEquals(2, helloWorld.readSingleRow().getCells().size());
+ assertEquals(1, helloWorld.readSpecificCells().size());
+ assertEquals(3, helloWorld.readTable().size());
+ }
 
  @Test
  public void testRunDoesNotFail() throws Exception {