Sample code for AGE-JDBC driver

drivers/jdbc/samples/AgeBasic.java

@@ -0,0 +1,134 @@
+import org.apache.age.jdbc.base.Agtype;
+import org.postgresql.jdbc.PgConnection;
+
+import java.sql.*;
+
+public class AgeBasic {
+
+    public static PgConnection connection;
+    static final String DB_URL = "jdbc:postgresql://localhost:5432/demo";
+    static final String USER = "postgres";
+    static final String PASS = "pass";
+
+    public static void main(String[] args) {
+
+        // Open a connection
+        try {
+            makeConnection();
+
+            if (graphExist("demo_graph"))
+                dropGraph();
+
+            createGraph();
+            getResult();
+            getObjectsFromResult();
+
+            // after all
+            dropGraph();
+            closeConnection();
+        }
+        catch (Exception e) {
+            System.out.println(e.getMessage());
+        }
+
+    }
+
+    /**
+     * Creating a connection with the database
+     * Loading AGE extension & configuring database for AGE
+     */
+    public static void makeConnection() throws SQLException {
+        connection = DriverManager.getConnection(DB_URL, USER, PASS).unwrap(PgConnection.class);
+        connection.addDataType("agtype", Agtype.class);
+
+        // configure AGE
+        Statement statement = connection.createStatement();
+        statement.execute("CREATE EXTENSION IF NOT EXISTS age;");
+        statement.execute("LOAD 'age'");
+        statement.execute("SET search_path = ag_catalog, \"$user\", public;");
+    }
+
+    /**
+     * Using Agtype parser on the ResultSet to get the result in Agtype.
+     */
+    public static void getResult() throws SQLException {
+        Statement stmt = connection.createStatement();
+        ResultSet rs = stmt.executeQuery("SELECT * from cypher('demo_graph', $$ MATCH (n) RETURN n $$) as (n agtype);");
+
+        // Returning result as Agtype
+        System.out.println("\nRESULT AS AGTYPE");
+        while (rs.next()) {
+            Agtype returnedAgtype = rs.getObject(1, Agtype.class);
+            System.out.println(returnedAgtype.getValue());
+        }
+    }
+
+    /**
+     * Using Agtype to extract specific objects from the Agtype result.
+     */
+    public static void getObjectsFromResult() throws SQLException {
+        Statement stmt = connection.createStatement();
+        ResultSet rs = stmt.executeQuery("SELECT * from cypher('demo_graph', $$ MATCH (n) RETURN n $$) as (n agtype);");
+
+        System.out.println("\nEXTRACTING OBJECTS FROM RESULT");
+        while (rs.next()) {
+            Agtype returnedAgtype = rs.getObject(1, Agtype.class);
+            String nodeLabel = returnedAgtype.getMap().getObject("label").toString();
+            String nodeProp = returnedAgtype.getMap().getObject("properties").toString();
+
+            System.out.println("Vertex : " + nodeLabel + ", \tProps : " + nodeProp);
+        }
+    }
+
+    /**
+     * Creating a 'demo_graph'.
+     * Then adding some Nodes.
+     * Then connecting them with some relation.
+     */
+    public static void createGraph() throws SQLException {
+        Statement statement = connection.createStatement();
+
+        // Nodes labeled as PERSON
+        statement.execute("SELECT create_graph('demo_graph');");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'imran', bornIn : 'Pakistan'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'ali', bornIn : 'Pakistan'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'usama', bornIn : 'Pakistan'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'akbar', bornIn : 'Pakistan'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'james', bornIn : 'US'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'david', bornIn : 'US'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Person {name : 'max', bornIn : 'US'}) $$) AS (a agtype);");
+
+        // Nodes labeled as COUNTRY
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Country{name : 'Pakistan'}) $$) AS (a agtype);");
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ CREATE (n:Country{name : 'US'}) $$) AS (a agtype);");
+
+        // creating relationship (n:PERSON)-[r:BORNIN]-(n:COUNTRY)
+        statement.execute("SELECT * FROM cypher('demo_graph', $$ MATCH (a:Person), (b:Country) WHERE a.bornIn = b.name CREATE (a)-[r:BORNIN]->(b) RETURN r $$) as (r agtype);");
+    }
+
+    /**
+     * After done querying drop the whole graph.
+     * Dropping the GRAPH with CASCADE:true. Deletes the whole data in the graph.
+     */
+    public static void dropGraph() throws SQLException {
+        Statement statement = connection.createStatement();
+        statement.execute("SELECT * FROM ag_catalog.drop_graph('demo_graph', true);");
+    }
+
+    public static boolean graphExist(String graph_name) throws SQLException {
+
+        PreparedStatement ps = connection.prepareStatement("SELECT * FROM ag_catalog.ag_graph WHERE name = ?");
+        ps.setString(1, graph_name);
+        ps.executeQuery();
+        ResultSet rs = ps.getResultSet();
+        return !(!rs.isBeforeFirst() && rs.getRow() == 0);
+    }
+
+    /**
+     * At last close the connection before exit.
+     */
+    public static void closeConnection() throws SQLException {
+        connection.close();
+    }
+
+}