Add TskDataModelChangeEvent class

Core/src/org/sleuthkit/autopsy/casemodule/events/TskDataModelChangeEvent.java

@@ -0,0 +1,112 @@
+/*
+ * Autopsy Forensic Browser
+ *
+ * Copyright 2021 Basis Technology Corp.
+ * Contact: carrier <at> sleuthkit <dot> org
+ *
+ * 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.sleuthkit.autopsy.casemodule.events;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.logging.Level;
+import org.sleuthkit.autopsy.casemodule.Case;
+import org.sleuthkit.autopsy.casemodule.NoCurrentCaseException;
+import org.sleuthkit.autopsy.coreutils.Logger;
+import org.sleuthkit.autopsy.events.AutopsyEvent;
+import org.sleuthkit.datamodel.SleuthkitCase;
+import org.sleuthkit.datamodel.TskCoreException;
+
+/**
+ * An application event generic used as a superclass for events published when
+ * something changes in the Sleuth Kit Data Model for a case.
+ *
+ * @param <T> A TSK Data Model object type.
+ */
+public abstract class TskDataModelChangeEvent<T> extends AutopsyEvent {
+
+    private static final long serialVersionUID = 1L;
+    private static final Logger logger = Logger.getLogger(TskDataModelChangeEvent.class.getName());
+    private final List<Long> dataModelObjectIds;
+    private transient List<T> dataModelObjects;
+
+    protected TskDataModelChangeEvent(String eventName, List<Long> dataModelObjectIds, List<T> dataModelObjects) {
+        super(eventName, null, null);
+        this.dataModelObjectIds = dataModelObjectIds;
+        this.dataModelObjects = dataModelObjects;
+        if (eventName == null) {
+            throw new IllegalArgumentException("eventName is null");
+        }
+        if (dataModelObjectIds == null) {
+            throw new IllegalArgumentException("dataModelObjectIds is null");
+        }
+        if (dataModelObjects == null) {
+            throw new IllegalArgumentException("dataModelObjects is null");
+        }
+    }
+
+    /**
+     * Gets the unique, numeric IDs (TSK object IDs, case database row IDs,
+     * etc.) of the Sleuth Kit Data Model objects associated with this
+     * application event.
+     *
+     * @return
+     */
+    public final List<T> getdataModelObjectIds() {
+        return Collections.unmodifiableList(dataModelObjects);
+    }
+
+    /**
+     * Gets the Sleuth Kit Data Model objects associated with this application
+     * event.
+     *
+     * @return
+     */
+    @Override
+    public List<T> getNewValue() {
+        /*
+         * If this event came from another host collaborating on a multi-user
+         * case, the transient list of Sleuth Kit Data Model objects will be
+         * null and will need to be reconstructed on the current host.
+         */
+        if (dataModelObjects == null) {
+            try {
+                Case currentCase = Case.getCurrentCaseThrows();
+                SleuthkitCase caseDb = currentCase.getSleuthkitCase();
+                dataModelObjects = getDataModelObjects(caseDb, dataModelObjectIds);
+            } catch (NoCurrentCaseException | TskCoreException ex) {
+                logger.log(Level.SEVERE, String.format("Error geting TSK Data Model objects for %s event (%s)", getPropertyName(), getSourceType()), ex);
+                return Collections.emptyList();
+            }
+        }
+        return Collections.unmodifiableList(dataModelObjects);
+    }
+
+    /**
+     * Gets the Sleuth Kit Data Model objects associated with this application
+     * event.
+     *
+     * @param caseDb The case database.
+     * @param ids    The unique, numeric IDs (TSK object IDs, case database row
+     *               IDs, etc.) of the Sleuth Kit Data Model objects.
+     *
+     * @return
+     *
+     * @throws org.sleuthkit.datamodel.TskCoreException If there is an error
+     *                                                  getting the Sleuth Kit
+     *                                                  Data Model objects.
+     */
+    abstract protected List<T> getDataModelObjects(SleuthkitCase caseDb, List<Long> ids) throws TskCoreException;
+
+}