Add ArangoDatabase.exists()

Author: mpv1989

ChangeLog

@@ -1,6 +1,7 @@
 v4.2.5 (2017-xx-xx)
 ---------------------------
 * issue #146: added ArangoCollection.exists()
+* added ArangoDatabase.exists()
 
 v4.2.4 (2017-09-04)
 ---------------------------

src/main/java/com/arangodb/ArangoCollection.java

@@ -781,7 +781,7 @@ public Collection<IndexEntity> getIndexes() throws ArangoDBException {
 	 * 
 	 * @return true if the collection exists, otherwise false
 	 */
-	public boolean exists() {
+	public boolean exists() throws ArangoDBException {
 		boolean exists = false;
 		final Collection<CollectionEntity> collections = db().getCollections();
 		for (final CollectionEntity collection : collections) {

src/main/java/com/arangodb/ArangoDatabase.java

@@ -90,6 +90,15 @@ public ArangoDBVersion getVersion() throws ArangoDBException {
 		return executor.execute(getVersionRequest(), ArangoDBVersion.class);
 	}
 
+	/**
+	 * Checks whether the database exists
+	 * 
+	 * @return true if the database exists, otherwise false
+	 */
+	public boolean exists() throws ArangoDBException {
+		return arango().getDatabases().contains(name());
+	}
+
 	/**
 	 * Retrieves a list of all databases the current user can access
 	 * 

src/test/java/com/arangodb/ArangoDatabaseTest.java

@@ -104,6 +104,12 @@ public void getVersion() {
 		assertThat(version.getVersion(), is(notNullValue()));
 	}
 
+	@Test
+	public void exists() {
+		assertThat(db.exists(), is(true));
+		assertThat(arangoDB.db("no").exists(), is(false));
+	}
+
 	@Test
 	public void getAccessibleDatabases() {
 		final Collection<String> dbs = db.getAccessibleDatabases();