[bs-15] Add audit abstraction and sensible opinionated defaults

* Added AuditEvent and AuditEventRepository
* Also AuditApplicationEvent and AuditListener for
handling AUditEvents as Spring ApplicationEvents

[Fixes #48155753]

spring-bootstrap-service/src/main/java/org/springframework/bootstrap/service/audit/AuditEvent.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit;
+
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A value object representing an audit event: at a particular time, a particular user or
+ * agent carried out an action of a particular type. This object records the details of
+ * such an event.
+ * 
+ * @author Dave Syer
+ * 
+ */
+public class AuditEvent {
+
+	final private Date timestamp;
+	final private String principal;
+	final private String type;
+	final private Map<String, Object> data;
+
+	/**
+	 * Create a new audit event for the current time from data provided as name-value
+	 * pairs
+	 */
+	public AuditEvent(String principal, String type, String... data) {
+		this(new Date(), principal, type, convert(data));
+	}
+
+	/**
+	 * Create a new audit event for the current time
+	 */
+	public AuditEvent(String principal, String type, Map<String, Object> data) {
+		this(new Date(), principal, type, data);
+	}
+
+	/**
+	 * Create a new audit event.
+	 */
+	public AuditEvent(Date timestamp, String principal, String type,
+			Map<String, Object> data) {
+		this.timestamp = timestamp;
+		this.principal = principal;
+		this.type = type;
+		this.data = Collections.unmodifiableMap(data);
+	}
+
+	public Date getTimestamp() {
+		return this.timestamp;
+	}
+
+	public String getPrincipal() {
+		return this.principal;
+	}
+
+	public String getType() {
+		return this.type;
+	}
+
+	public Map<String, Object> getData() {
+		return this.data;
+	}
+
+	private static Map<String, Object> convert(String[] data) {
+		Map<String, Object> result = new HashMap<String, Object>();
+		for (String entry : data) {
+			if (entry.contains("=")) {
+				int index = entry.indexOf("=");
+				result.put(entry.substring(0, index), entry.substring(index + 1));
+			} else {
+				result.put(entry, null);
+			}
+		}
+		return result;
+	}
+
+}

spring-bootstrap-service/src/main/java/org/springframework/bootstrap/service/audit/AuditEventRepository.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit;
+
+import java.util.Date;
+import java.util.List;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public interface AuditEventRepository {
+
+	/**
+	 * Find audit events relating to the specified principal since the time provided.
+	 * 
+	 * @param principal the principal name to search for
+	 * @param after timestamp of earliest result required
+	 * @return audit events relating to the principal
+	 */
+	List<AuditEvent> find(String principal, Date after);
+
+	/**
+	 * Log an event.
+	 * 
+	 * @param event the audit event to log
+	 */
+	void add(AuditEvent event);
+
+}

spring-bootstrap-service/src/main/java/org/springframework/bootstrap/service/audit/InMemoryAuditEventRepository.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class InMemoryAuditEventRepository implements AuditEventRepository {
+
+	private int capacity = 100;
+
+	private Map<String, List<AuditEvent>> events = new HashMap<String, List<AuditEvent>>();
+
+	/**
+	 * @param capacity the capacity to set
+	 */
+	public void setCapacity(int capacity) {
+		this.capacity = capacity;
+	}
+
+	@Override
+	public List<AuditEvent> find(String principal, Date after) {
+		synchronized (this.events) {
+			return Collections.unmodifiableList(getEvents(principal));
+		}
+	}
+
+	private List<AuditEvent> getEvents(String principal) {
+		if (!this.events.containsKey(principal)) {
+			this.events.put(principal, new ArrayList<AuditEvent>());
+		}
+		return this.events.get(principal);
+	}
+
+	@Override
+	public void add(AuditEvent event) {
+		synchronized (this.events) {
+			List<AuditEvent> list = getEvents(event.getPrincipal());
+			while (list.size() >= this.capacity) {
+				list.remove(0);
+			}
+			list.add(event);
+		}
+	}
+
+}

spring-bootstrap-service/src/main/java/org/springframework/bootstrap/service/audit/listener/AuditApplicationEvent.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit.listener;
+
+import org.springframework.bootstrap.service.audit.AuditEvent;
+import org.springframework.context.ApplicationEvent;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class AuditApplicationEvent extends ApplicationEvent {
+
+	private AuditEvent auditEvent;
+
+	/**
+	 * @param auditEvent the source of this event
+	 */
+	public AuditApplicationEvent(AuditEvent auditEvent) {
+		super(auditEvent);
+		this.auditEvent = auditEvent;
+	}
+
+	/**
+	 * @return the audit event
+	 */
+	public AuditEvent getAuditEvent() {
+		return this.auditEvent;
+	}
+}

spring-bootstrap-service/src/main/java/org/springframework/bootstrap/service/audit/listener/AuditListener.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit.listener;
+
+import org.springframework.bootstrap.service.audit.AuditEventRepository;
+import org.springframework.context.ApplicationListener;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class AuditListener implements ApplicationListener<AuditApplicationEvent> {
+
+	private final AuditEventRepository auditEventRepository;
+
+	public AuditListener(AuditEventRepository auditEventRepository) {
+		this.auditEventRepository = auditEventRepository;
+	}
+
+	@Override
+	public void onApplicationEvent(AuditApplicationEvent event) {
+		this.auditEventRepository.add(event.getAuditEvent());
+	}
+
+}

spring-bootstrap-service/src/test/java/org/springframework/bootstrap/service/audit/AuditEventTests.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit;
+
+import java.util.Collections;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class AuditEventTests {
+
+	@Test
+	public void testNowEvent() throws Exception {
+		AuditEvent event = new AuditEvent("phil", "UNKNOWN", Collections.singletonMap(
+				"a", (Object) "b"));
+		assertEquals("b", event.getData().get("a"));
+		assertEquals("UNKNOWN", event.getType());
+		assertEquals("phil", event.getPrincipal());
+		assertNotNull(event.getTimestamp());
+	}
+
+	@Test
+	public void testConvertStringsToData() throws Exception {
+		AuditEvent event = new AuditEvent("phil", "UNKNOWN", "a=b", "c=d");
+		assertEquals("b", event.getData().get("a"));
+		assertEquals("d", event.getData().get("c"));
+	}
+
+}

spring-bootstrap-service/src/test/java/org/springframework/bootstrap/service/audit/InMemoryAuditEventRepositoryTests.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.service.audit;
+
+import java.util.Date;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class InMemoryAuditEventRepositoryTests {
+
+	private InMemoryAuditEventRepository repository = new InMemoryAuditEventRepository();
+
+	@Test
+	public void testAddToCapacity() throws Exception {
+		this.repository.setCapacity(2);
+		this.repository.add(new AuditEvent("phil", "UNKNOWN"));
+		this.repository.add(new AuditEvent("phil", "UNKNOWN"));
+		this.repository.add(new AuditEvent("dave", "UNKNOWN"));
+		this.repository.add(new AuditEvent("dave", "UNKNOWN"));
+		this.repository.add(new AuditEvent("phil", "UNKNOWN"));
+		assertEquals(2, this.repository.find("phil", new Date(0L)).size());
+	}
+
+}