+
−/*
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− * This Source Code Form is subject to the terms of the Mozilla Public
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− * License, v. 2.0.  If a copy of the MPL was not distributed with this
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− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
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− * Copyright 1997 - July 2008 CWI, August 2008 - 2021 MonetDB B.V.
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− */
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−
+
−import org.monetdb.jdbc.MonetConnection;
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−import org.monetdb.jdbc.MonetConnection.UploadHandler;
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−
+
−import java.io.BufferedReader;
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−import java.io.IOException;
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−import java.io.InputStream;
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−import java.io.PrintStream;
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−import java.nio.file.FileSystems;
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−import java.nio.file.Files;
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−import java.nio.file.Path;
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−import java.sql.*;
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−
+
−public class OnClientExample {
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−
+
−	public static void main(String[] args) {
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−		int status;
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−		try {
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−			// Ideally this would not be hardcoded..
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−			final String dbUrl = "jdbc:monetdb://localhost:50000/demo";
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−			final String userName = "monetdb";
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−			final String password = "monetdb";
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−			final String uploadDir = "/home/jvr/mydata";
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−			final boolean filesAreUtf8 = false;
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−			String[] queries = {
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−					"DROP TABLE IF EXISTS mytable",
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−					"CREATE TABLE mytable(i INT, t TEXT)",
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−					"COPY INTO mytable FROM 'generated.csv' ON CLIENT",
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−					"COPY 20 RECORDS OFFSET 5 INTO mytable FROM 'generated.csv' ON CLIENT",
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−					"COPY INTO mytable FROM 'nonexistentfilethatdoesnotexist.csv' ON CLIENT",
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−					"SELECT COUNT(*) FROM mytable",
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−			};
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−
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−			status = run(dbUrl, userName, password, uploadDir, filesAreUtf8, queries);
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−
+
−		} catch (Exception e) {
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−			status = 1;
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−			e.printStackTrace();
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−		}
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−		System.exit(status);
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−	}
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−
+
−	private static int run(String dbUrl, String userName, String password, String uploadDir, boolean filesAreUtf8, String[] queries) throws ClassNotFoundException, SQLException {
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−		int status = 0;
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−
+
−		// Connect
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−		Class.forName("org.monetdb.jdbc.MonetDriver");
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−		Connection conn = DriverManager.getConnection(dbUrl, userName, password);
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−
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−		// Register upload handler
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−		MyUploader handler = new MyUploader(uploadDir, filesAreUtf8);
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−		conn.unwrap(MonetConnection.class).setUploadHandler(handler);
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−
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−		Statement stmt = conn.createStatement();
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−		for (String q : queries) {
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−			System.out.println(q);
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−			try {
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−				boolean hasResultSet = stmt.execute(q);
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−				if (hasResultSet) {
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−					ResultSet rs = stmt.getResultSet();
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−					long count = 0;
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−					while (rs.next()) {
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−						count++;
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−					}
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−					System.out.printf("  OK, returned %d rows%n", count);
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−				} else {
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−					System.out.printf("  OK, updated %d rows%n", stmt.getUpdateCount());
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−				}
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−			} catch (SQLNonTransientException e) {
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−				throw e;
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−			} catch (SQLException e) {
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−				System.out.println("  => SQL ERROR " + e.getMessage());
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−				status = 1;
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−			}
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−
+
−		}
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−
+
−		return status;
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−	}
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−
+
−
+
−	private static class MyUploader implements UploadHandler {
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−		private final Path uploadDir;
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−		private final boolean filesAreUtf8;
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−		private boolean stopUploading = false;
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−
+
−		public MyUploader(String uploadDir, boolean filesAreUtf8) {
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−			this.uploadDir = FileSystems.getDefault().getPath(uploadDir).normalize();
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−			this.filesAreUtf8 = filesAreUtf8;
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−		}
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−
+
−		@Override
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−		public void uploadCancelled() {
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−			System.out.println("  CANCELLATION CALLBACK: server cancelled the upload");
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−			stopUploading = true;
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−		}
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−
+
−		@Override
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−		public void handleUpload(MonetConnection.Upload handle, String name, boolean textMode, long linesToSkip) throws IOException {
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−
+
−			// We can upload data read from the file system but also make up our own data
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−			if (name.equals("generated.csv")) {
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−				uploadGeneratedData(handle, linesToSkip);
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−				return;
+
−			}
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−
+
−			// Validate the path, demonstrating two ways of dealing with errors
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−			Path path = securityCheck(name);
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−			if (path == null || !Files.exists(path)) {
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−				// This makes the COPY command fail but keeps the connection
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−				// alive. Can only be used if we haven't sent any data yet
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−				handle.sendError("Invalid path");
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−				return;
+
−			}
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−			if (!Files.isReadable(path)) {
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−				// As opposed to handle.sendError(), we can throw an IOException
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−				// at any time. Unfortunately, the file upload protocol does not
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−				// provide a way to indicate to the server that the data sent so
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−				// far is incomplete, so for the time being throwing an
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−				// IOException from {@handleUpload} terminates the connection.
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−				throw new IOException("Unreadable: " + path);
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−			}
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−
+
−			boolean binary = !textMode;
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−			if (binary) {
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−				uploadAsBinary(handle, path);
+
−			} else if (linesToSkip == 0 && filesAreUtf8) {
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−				// Avoid unnecessary UTF-8 -> Java String -> UTF-8 conversions
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−				// by pretending the data is binary.
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−				uploadAsBinary(handle, path);
+
−			} else {
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−				// Charset and skip handling really necessary
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−				uploadAsText(handle, path, linesToSkip);
+
−			}
+
−		}
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−
+
−		private Path securityCheck(String name) {
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−			Path p = uploadDir.resolve(name).normalize();
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−			if (p.startsWith(uploadDir)) {
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−				return p;
+
−			} else {
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−				return null;
+
−			}
+
−		}
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−
+
−		private void uploadGeneratedData(MonetConnection.Upload handle, long toSkip) throws IOException {
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−			// Set the chunk size to a tiny amount so we can demonstrate
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−			// cancellation handling. The default chunk size is one megabyte.
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−			// DO NOT DO THIS IN PRODUCTION!
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−			handle.setChunkSize(50);
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−
+
−			// Make up some data and upload it.
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−			PrintStream stream = handle.getStream();
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−			long n = 100;
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−			System.out.printf("  HANDLER: uploading %d generated lines, numbered %d to %d%n", n - toSkip, toSkip + 1, n);
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−			long i;
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−			for (i = toSkip + 1; i <= n; i++) {
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−				if (stopUploading) {
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−					System.out.printf("  HANDLER: at line %d we noticed the server asked us to stop sending%n", i);
+
−					break;
+
−				}
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−				stream.printf("%d|the number is %d%n", i, i);
+
−			}
+
−			System.out.println("  HANDLER: done uploading");
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−			stream.close();
+
−		}
+
−
+
−		private void uploadAsText(MonetConnection.Upload handle, Path path, long toSkip) throws IOException {
+
−			BufferedReader reader = Files.newBufferedReader(path);// Converts from system encoding to Java text
+
−			for (long i = 0; i < toSkip; i++) {
+
−				reader.readLine();
+
−			}
+
−			handle.uploadFrom(reader); // Converts from Java text to UTF-8 as required by MonetDB
+
−		}
+
−
+
−		private void uploadAsBinary(MonetConnection.Upload handle, Path path) throws IOException {
+
−			// No charset conversion whatsoever..
+
−			// Use this for binary data or when you are certain the file is UTF-8 encoded.
+
−			InputStream stream = Files.newInputStream(path);
+
−			handle.uploadFrom(stream);
+
−		}
+
−	}
+
−}