Add template for assignment 1

ass1-kv/src/main/java/dst/ass1/kv/ISessionManager.java

@@ -0,0 +1,69 @@
+package dst.ass1.kv;
+
+public interface ISessionManager {
+
+    /**
+     * Creates a new session id and stores the userId and session timeout under the given id in the session store.
+     *
+     * @param userId     the user to create the session for
+     * @param timeToLive the session timeout after which the session expires in seconds
+     * @return the session id.
+     * @throws SessionCreationFailedException if the session couldn't be created, e.g., due to a failed transaction
+     */
+    String createSession(Long userId, int timeToLive) throws SessionCreationFailedException;
+
+    /**
+     * Sets a key--value pair in the given session.
+     *
+     * @param sessionId the session to store the variable in
+     * @param key       the name of the variable
+     * @param value     the value
+     * @throws SessionNotFoundException if the session wasn't found
+     */
+    void setSessionVariable(String sessionId, String key, String value) throws SessionNotFoundException;
+
+    /**
+     * Returns the value of the given session variable.
+     *
+     * @param sessionId the session id
+     * @param key       the name of the variable
+     * @return the variable value, or null if it doesn't exist
+     * @throws SessionNotFoundException if the given session id has expired or doesn't exist
+     */
+    String getSessionVariable(String sessionId, String key) throws SessionNotFoundException;
+
+    /**
+     * Returns the user to whom the given session belongs.
+     *
+     * @param sessionId the session id
+     * @return the user id
+     * @throws SessionNotFoundException if the given session id has expired or doesn't exist
+     */
+    Long getUserId(String sessionId) throws SessionNotFoundException;
+
+    /**
+     * Returns the current time-to-live for the given session.
+     *
+     * @param sessionId the session id
+     * @return the session ttl in seconds
+     * @throws SessionNotFoundException if the given session id has expired or doesn't exist
+     */
+    int getTimeToLive(String sessionId) throws SessionNotFoundException;
+
+    /**
+     * Checks whether the given user has an open session, if so, the session id is returned (and the timeout
+     * parameter ignored), otherwise a new session is created with the given timeout and the newly generated id is
+     * returned.
+     *
+     * @param userId     the user to require the session for
+     * @param timeToLive the session timeout after which the session expires in seconds
+     * @return the session id.
+     * @throws SessionCreationFailedException if the session couldn't be created, e.g., due to a failed transaction
+     */
+    String requireSession(Long userId, int timeToLive) throws SessionCreationFailedException;
+
+    /**
+     * Closes whatever underlying connection is required to maintain the session manager.
+     */
+    void close();
+}

ass1-kv/src/main/java/dst/ass1/kv/ISessionManagerFactory.java

@@ -0,0 +1,13 @@
+package dst.ass1.kv;
+
+import java.util.Properties;
+
+public interface ISessionManagerFactory {
+    /**
+     * Creates an implementation of an {@link ISessionManager}.
+     *
+     * @param properties the properties to use for instantiation
+     * @return a session manager object
+     */
+    ISessionManager createSessionManager(Properties properties);
+}

ass1-kv/src/main/java/dst/ass1/kv/SessionCreationFailedException.java

@@ -0,0 +1,25 @@
+package dst.ass1.kv;
+
+/**
+ * Exception indicating that a request to create a new session could not be fulfilled.
+ */
+public class SessionCreationFailedException extends Exception {
+
+    private static final long serialVersionUID = 1L;
+
+    public SessionCreationFailedException() {
+    }
+
+    public SessionCreationFailedException(String message) {
+        super(message);
+    }
+
+    public SessionCreationFailedException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public SessionCreationFailedException(Throwable cause) {
+        super(cause);
+    }
+
+}

ass1-kv/src/main/java/dst/ass1/kv/SessionNotFoundException.java

@@ -0,0 +1,24 @@
+package dst.ass1.kv;
+
+/**
+ * Exception to indicate that <i>this is not the session you are looking for</i>.
+ */
+public class SessionNotFoundException extends Exception {
+
+    private static final long serialVersionUID = 1L;
+
+    public SessionNotFoundException() {
+    }
+
+    public SessionNotFoundException(String message) {
+        super(message);
+    }
+
+    public SessionNotFoundException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public SessionNotFoundException(Throwable cause) {
+        super(cause);
+    }
+}

ass1-kv/src/main/java/dst/ass1/kv/impl/SessionManagerFactory.java

@@ -0,0 +1,17 @@
+package dst.ass1.kv.impl;
+
+import dst.ass1.kv.ISessionManager;
+import dst.ass1.kv.ISessionManagerFactory;
+
+import java.util.Properties;
+
+public class SessionManagerFactory implements ISessionManagerFactory {
+
+    @Override
+    public ISessionManager createSessionManager(Properties properties) {
+        // TODO
+        // read "redis.host" and "redis.port" from the properties
+
+        return null;
+    }
+}

ass1-kv/src/test/java/dst/ass1/kv/RedisCleaner.java

@@ -0,0 +1,60 @@
+package dst.ass1.kv;
+
+import org.junit.rules.ExternalResource;
+import redis.clients.jedis.Jedis;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+
+/**
+ * Drops the entire key space of a redis instance before and after a test run.
+ */
+public class RedisCleaner extends ExternalResource {
+
+    private Properties properties;
+    private Jedis jedis;
+
+    @Override
+    protected void before() throws IOException {
+        properties = loadProperties();
+
+        String host = properties.getProperty("redis.host");
+        int port = Integer.parseInt(properties.getProperty("redis.port"));
+        jedis = new Jedis(host, port);
+
+        // completely clear the redis instance before each test
+        jedis.flushAll();
+    }
+
+    @Override
+    protected void after() {
+        // completely clear the redis instance after each test
+        try {
+            jedis.flushAll();
+        } finally {
+            // close the connection pool
+            jedis.close();
+        }
+    }
+
+    /**
+     * @return loaded redis properties
+     */
+    public Properties getProperties() {
+        return properties;
+    }
+
+    public Jedis getJedis() {
+        return jedis;
+    }
+
+    private Properties loadProperties() throws IOException {
+        Properties properties = new Properties();
+        try (InputStream in = getClass().getClassLoader().getResourceAsStream("redis.properties")) {
+            properties.load(in);
+        }
+        return properties;
+    }
+
+}

ass1-kv/src/test/java/dst/ass1/kv/tests/Ass1_5_1Test.java

@@ -0,0 +1,102 @@
+package dst.ass1.kv.tests;
+
+import dst.ass1.kv.ISessionManager;
+import dst.ass1.kv.ISessionManagerFactory;
+import dst.ass1.kv.RedisCleaner;
+import dst.ass1.kv.SessionNotFoundException;
+import dst.ass1.kv.impl.SessionManagerFactory;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.*;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.*;
+
+public class Ass1_5_1Test {
+
+    @Rule
+    public RedisCleaner redisRule = new RedisCleaner();
+
+    private ISessionManager sessionManager;
+
+    @Before
+    public void setUp() {
+        ISessionManagerFactory sessionManagerFactory = new SessionManagerFactory();
+
+        sessionManager = sessionManagerFactory.createSessionManager(redisRule.getProperties());
+    }
+
+    @After
+    public void tearDown() {
+        sessionManager.close();
+    }
+
+    @Test
+    public void createSession_createsSessionId() throws Exception {
+        String sessionId = sessionManager.createSession(1337L, 15000);
+        assertNotNull(sessionId);
+    }
+
+    @Test
+    public void getAndSetSessionVariable_behavesCorrectly() throws Exception {
+        String sessionId = sessionManager.createSession(1337L, 15000);
+        sessionManager.setSessionVariable(sessionId, "f00", "bar");
+        assertEquals("bar", sessionManager.getSessionVariable(sessionId, "f00"));
+    }
+
+    @Test(expected = SessionNotFoundException.class)
+    public void setSessionVariable_forNonExistingSession_throwsSessionNotFoundException() throws Exception {
+        sessionManager.setSessionVariable("nonExistingSessionId", "f00", "bar");
+    }
+
+    @Test(expected = SessionNotFoundException.class)
+    public void getSessionVariable_forNonExistingSession_throwsSessionNotFoundException() throws Exception {
+        sessionManager.getSessionVariable("nonExistingSessionId", "f00");
+    }
+
+    @Test
+    public void getSessionVariable_onNonExistingVariable_returnsNull() throws Exception {
+        String sessionId = sessionManager.createSession(1337L, 15000);
+        String value = sessionManager.getSessionVariable(sessionId, "f00");
+        assertNull(value);
+    }
+
+    @Test
+    public void getUserId_returnsCorrectUserID() throws Exception {
+        Long userId = 1337L;
+        String sessionId = sessionManager.createSession(userId, 15000);
+        assertEquals(userId, sessionManager.getUserId(sessionId));
+    }
+
+    @Test(expected = SessionNotFoundException.class)
+    public void getUserId_forNonExistingSession_throwsException() throws Exception {
+        sessionManager.getUserId("nonExistingSessionId");
+    }
+
+    @Test
+    public void getTimeToLive_returnsCorrectValue() throws Exception {
+        String sessionId = sessionManager.createSession(1337L, 60);
+        int ttl = sessionManager.getTimeToLive(sessionId);
+        assertThat(ttl, allOf(greaterThan(57), lessThan(61)));
+    }
+
+    @Test
+    public void getTimeToLive_afterExpiry_throwsSessionNotFoundException() throws Exception {
+        String sessionId = sessionManager.createSession(1337L, 2);
+        int ttl = sessionManager.getTimeToLive(sessionId);
+        assertThat(ttl, greaterThan(0));
+        Thread.sleep(3000);
+
+        assertThrows(SessionNotFoundException.class, () -> {
+            sessionManager.getTimeToLive(sessionId);
+        });
+    }
+
+    @Test(expected = SessionNotFoundException.class)
+    public void getTimeToLive_forNonExistingSession_throwsSessionNotFoundException() throws Exception {
+        sessionManager.getTimeToLive("nonExistingSessionId");
+    }
+
+}

ass1-kv/src/test/java/dst/ass1/kv/tests/Ass1_5_2Test.java

@@ -0,0 +1,50 @@
+package dst.ass1.kv.tests;
+
+import dst.ass1.kv.ISessionManager;
+import dst.ass1.kv.ISessionManagerFactory;
+import dst.ass1.kv.RedisCleaner;
+import dst.ass1.kv.impl.SessionManagerFactory;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+public class Ass1_5_2Test {
+
+    @Rule
+    public RedisCleaner redisRule = new RedisCleaner();
+
+    private ISessionManager sessionManager;
+
+    @Before
+    public void setUp() {
+        ISessionManagerFactory sessionManagerFactory = new SessionManagerFactory();
+
+        sessionManager = sessionManagerFactory.createSessionManager(redisRule.getProperties());
+    }
+
+    @After
+    public void tearDown() {
+        sessionManager.close();
+    }
+
+    @Test
+    public void testRequireSessionForExistingSession_existingIdReturned() throws Exception {
+        String newId = sessionManager.createSession(1337L, 30000);
+        assertNotNull(newId);
+
+        String requiredId = sessionManager.requireSession(1337L, 15000);
+        assertEquals(newId, requiredId);
+    }
+
+    @Test
+    public void testRequireSessionForNonExistingSession_newSessionCreated() throws Exception {
+        String sessionId = sessionManager.requireSession(1337L, 15000);
+
+        assertEquals(Long.valueOf(1337L), sessionManager.getUserId(sessionId));
+    }
+
+}

ass1-kv/src/test/java/dst/ass1/kv/tests/Ass1_5_Suite.java

@@ -0,0 +1,13 @@
+package dst.ass1.kv.tests;
+
+import org.junit.runner.RunWith;
+import org.junit.runners.Suite;
+import org.junit.runners.Suite.SuiteClasses;
+
+@RunWith(Suite.class)
+@SuiteClasses( {
+    Ass1_5_1Test.class,
+    Ass1_5_2Test.class
+})
+public class Ass1_5_Suite {
+}

ass1-kv/src/test/resources/logback.xml

@@ -0,0 +1,14 @@
+<configuration>
+
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <!-- encoders are assigned the type  ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
+    <encoder>
+      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} - %highlight(%5p) [%12.12thread] %cyan(%-40.40logger{39}): %m%n</pattern>
+    </encoder>
+
+  </appender>
+
+  <root level="${log.level:-INFO}">
+    <appender-ref ref="STDOUT"/>
+  </root>
+</configuration>

ass1-kv/src/test/resources/redis.properties

@@ -0,0 +1,4 @@
+# you can change this to, e.g., 127.0.0.1 if you have a local redis instance
+redis.host=192.168.99.99
+#redis.host=127.0.0.1
+redis.port=6379