use SPI for dialect initialization

Author: alexradzin

build.gradle

@@ -32,7 +32,6 @@ dependencies {
     testCompile group: 'junit', name: 'junit', version: '4.12'
     implementation 'com.upsolver:data-sources-interfaces:1.0.7'
 
-
     implementation group: 'com.amazon.redshift', name: 'redshift-jdbc42', version: '1.2.1.1001'
     implementation "mysql:mysql-connector-java:8.0.14"
     implementation "com.oracle.ojdbc:ojdbc8:19.3.0.0"

src/main/java/com/upsolver/datasources/jdbc/querybuilders/DefaultQueryDialect.java

@@ -282,4 +282,9 @@ public String getDriverClassName() {
     public ThrowingBiFunction<ResultSet, Integer, Object, SQLException> getValueGetter(int sqlType) {
         return valueGetters.getOrDefault(sqlType, defaultValueGetter);
     }
+
+    @Override
+    public boolean acceptsURL(String url) {
+        return url.startsWith("jdbc:");
+    }
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/OracleQueryDialect.java

@@ -108,4 +108,9 @@ public SQLType getJdbcType(SQLType sqlType) {
         }
         return sqlType;
     }
+
+    @Override
+    public boolean acceptsURL(String url) {
+        return url.startsWith("jdbc:oracle:");
+    }
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/PostgreSqlQueryDialect.java

@@ -27,4 +27,9 @@ public boolean isAutoIncrementColumn(ResultSet columnsResultSet) throws SQLExcep
     public String getDriverClassName() {
         return "org.postgresql.Driver";
     }
+
+    @Override
+    public boolean acceptsURL(String url) {
+        return url.startsWith("jdbc:postgresql:");
+    }
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/QueryDialect.java

@@ -71,4 +71,8 @@ NamedPreparedStatment queryFullTable(TableInfo tableInfo,
     String getDriverClassName();
 
     ThrowingBiFunction<ResultSet, Integer, Object, SQLException> getValueGetter(int sqlType);
+
+    ThrowingBiFunction<ResultSet, Integer, String, SQLException> getStringValueGetter(int sqlType);
+
+    boolean acceptsURL(String url);
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/QueryDialectProvider.java

@@ -1,20 +1,15 @@
 package com.upsolver.datasources.jdbc.querybuilders;
 
-public class QueryDialectProvider {
+import java.util.ServiceLoader;
+import java.util.stream.StreamSupport;
 
-    public static QueryDialect forConnection(String connectionString, boolean keepTypes) {
+public class QueryDialectProvider {
+    public static QueryDialect forConnection(String connectionString) {
         String connStr = connectionString.toLowerCase();
-        if (connStr.startsWith("jdbc:sqlserver")) {
-            return new SqlServerQueryDialect(keepTypes);
-        } else if (connStr.startsWith("jdbc:oracle")) {
-            return new OracleQueryDialect(keepTypes);
-        } else if (connStr.startsWith("jdbc:redshift")) {
-            return new RedshiftQueryDialect(keepTypes);
-        } else if (connStr.startsWith("jdbc:postgresql")) {
-            return new PostgreSqlQueryDialect(keepTypes);
-        } else if (connStr.startsWith("jdbc:snowflake")) {
-            return new SnowflakeQueryDialect(keepTypes);
-        }
-        return new DefaultQueryDialect(keepTypes);
+        Iterable<QueryDialect> iterable = () -> ServiceLoader.load(QueryDialect.class).iterator();
+        return StreamSupport.stream(iterable.spliterator(), false)
+                .filter(d -> d.acceptsURL(connStr))
+                .findFirst()
+                .orElseGet(DefaultQueryDialect::new);
     }
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/RedshiftQueryDialect.java

@@ -22,4 +22,9 @@ public boolean isAutoIncrementColumn(ResultSet columnsResultSet) throws SQLExcep
         // Example default value: "identity"(707455, 0, '1,1'::text)
         return def != null && def.startsWith("\"identity\"(");
     }
+
+    @Override
+    public boolean acceptsURL(String url) {
+        return url.startsWith("jdbc:redshift:");
+    }
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/SnowflakeQueryDialect.java

@@ -19,4 +19,9 @@ public long utcOffsetSeconds(Connection connection) throws SQLException {
     public boolean requiresUppercaseNames() {
         return true;
     }
+
+    @Override
+    public boolean acceptsURL(String url) {
+        return url.startsWith("jdbc:snowflake:");
+    }
 }

src/main/java/com/upsolver/datasources/jdbc/querybuilders/SqlServerQueryDialect.java

@@ -61,4 +61,9 @@ private static int getIntValue(Field field) {
             throw new IllegalStateException(e);
         }
     }
+
+    @Override
+    public boolean acceptsURL(String url) {
+        return url.startsWith("jdbc:sqlserver:");
+    }
 }

src/main/resources/META-INF/services/com.upsolver.datasources.jdbc.querybuilders.QueryDialect

@@ -0,0 +1,6 @@
+com.upsolver.datasources.jdbc.querybuilders.SqlServerQueryDialect
+com.upsolver.datasources.jdbc.querybuilders.OracleQueryDialect
+com.upsolver.datasources.jdbc.querybuilders.RedshiftQueryDialect
+com.upsolver.datasources.jdbc.querybuilders.PostgreSqlQueryDialect
+com.upsolver.datasources.jdbc.querybuilders.SnowflakeQueryDialect
+com.upsolver.datasources.jdbc.querybuilders.DefaultQueryDialect

src/test/java/com/upsolver/datasources/jdbc/querybuilders/QueryDialectProviderTest.java

@@ -0,0 +1,42 @@
+package com.upsolver.datasources.jdbc.querybuilders;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class QueryDialectProviderTest {
+    @Test
+    public void testDefault() {
+        test("jdbc:unknown", DefaultQueryDialect.class);
+    }
+
+
+    @Test
+    public void sqlServer() {
+        test("jdbc:sqlserver://database-1.foo.us-east-1.rds.amazonaws.com:1433", SqlServerQueryDialect.class);
+    }
+
+    @Test
+    public void oracle() {
+        test("jdbc:oracle:thin:@//temp-oracle.foo.us-east-1.rds.amazonaws.com:1521/test", OracleQueryDialect.class);
+    }
+
+    @Test
+    public void redshift() {
+        test("jdbc:redshift://redshift-cluster-1.foo.us-east-1.redshift.amazonaws.com:5439/dev", RedshiftQueryDialect.class);
+    }
+
+    @Test
+    public void postgres() {
+        test("jdbc:postgresql://1.1.1.1:5432/test_db", PostgreSqlQueryDialect.class);
+    }
+
+    @Test
+    public void snowflake() {
+        test("jdbc:snowflake://oka43275.us-east-1.snowflakecomputing.com?db=demo_db&warehouse=test1", SnowflakeQueryDialect.class);
+    }
+
+    private void test(String url, Class<? extends QueryDialect> expectedDialectClass) {
+        assertEquals(expectedDialectClass, QueryDialectProvider.forConnection(url).getClass());
+    }
+}