Merge pull request #264 from oscerd/influxdb-263

Resolves #263 Add databaseExists method to InfluxDB interface

Author: majst01

CHANGELOG.md

@@ -3,8 +3,12 @@
 #### Features
 
  - Support chunking
+ - Add a databaseExists method to InfluxDB interface 
 
 #### Fixes
+
+ - [Issue #263] (https://github.com/influxdata/influxdb-java/issues/263) Add databaseExists method to InfluxDB interface.
+
 #### Improvements
 
 

src/main/java/org/influxdb/InfluxDB.java

@@ -263,6 +263,16 @@ public void write(final String database, final String retentionPolicy,
    */
   public List<String> describeDatabases();
 
+  /**
+   * Check if a database exists.
+   *
+   * @param name
+   *            the name of the database to search.
+   *
+   * @return true if the database exists or false if it doesn't exist
+   */
+  public boolean databaseExists(final String name);
+
   /**
    * close thread for asynchronous batch write and UDP socket to release resources if need.
    */

src/main/java/org/influxdb/impl/InfluxDBImpl.java

@@ -430,6 +430,20 @@ public List<String> describeDatabases() {
     return databases;
   }
 
+  /**
+   * {@inheritDoc}
+   */
+  @Override
+  public boolean databaseExists(final String name) {
+    List<String> databases = this.describeDatabases();
+    for (String databaseName : databases) {
+      if (databaseName.trim().equals(name)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   private <T> T execute(final Call<T> call) {
     try {
       Response<T> response = call.execute();

src/test/java/org/influxdb/InfluxDBTest.java

@@ -133,6 +133,21 @@ public void testDescribeDatabases() {
 		Assert.assertTrue("It is expected that describeDataBases contents the newly create database.", found);
 		this.influxDB.deleteDatabase(dbName);
 	}
+	
+	/**
+	 * Test that Database exists works.
+	 */
+	@Test
+	public void testDatabaseExists() {
+		String existentdbName = "unittest_1";
+		String notExistentdbName = "unittest_2";
+		this.influxDB.createDatabase(existentdbName);
+		boolean checkDbExistence = this.influxDB.databaseExists(existentdbName);
+		Assert.assertTrue("It is expected that databaseExists return true for " + existentdbName + " database", checkDbExistence);
+		checkDbExistence = this.influxDB.databaseExists(notExistentdbName);
+		Assert.assertFalse("It is expected that databaseExists return false for " + notExistentdbName + " database", checkDbExistence);
+		this.influxDB.deleteDatabase(existentdbName);
+	}
 
 	/**
 	 * Test that writing to the new lineprotocol.