NIFI-15480: Added DropFlowFileSummary, ability to drop FlowFiles from a ConnectionFacade / ProcessGroupFacade (#62)

Author: markap14

src/main/java/org/apache/nifi/components/connector/DropFlowFileSummary.java

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.nifi.components.connector;
+
+/**
+ * A summary of FlowFiles that were dropped from a FlowFile Queue.
+ * This class provides information about the number of FlowFiles dropped
+ * and the total aggregate size in bytes of those FlowFiles.
+ */
+public class DropFlowFileSummary {
+
+    private final int droppedCount;
+    private final long droppedBytes;
+
+    /**
+     * Creates a new DropFlowFileSummary with the given count and byte size.
+     *
+     * @param droppedCount the number of FlowFiles that were dropped
+     * @param droppedBytes the total size in bytes of all dropped FlowFiles
+     */
+    public DropFlowFileSummary(final int droppedCount, final long droppedBytes) {
+        this.droppedCount = droppedCount;
+        this.droppedBytes = droppedBytes;
+    }
+
+    /**
+     * @return the number of FlowFiles that were dropped
+     */
+    public int getDroppedCount() {
+        return droppedCount;
+    }
+
+    /**
+     * @return the total size in bytes of all dropped FlowFiles
+     */
+    public long getDroppedBytes() {
+        return droppedBytes;
+    }
+
+    /**
+     * Creates a new DropFlowFileSummary that represents the combination of this summary and the given summary.
+     *
+     * @param other the other summary to add to this one
+     * @return a new DropFlowFileSummary representing the combined totals
+     */
+    public DropFlowFileSummary add(final DropFlowFileSummary other) {
+        return new DropFlowFileSummary(this.droppedCount + other.droppedCount, this.droppedBytes + other.droppedBytes);
+    }
+
+    @Override
+    public String toString() {
+        return "DropFlowFileSummary[droppedCount=" + droppedCount + ", droppedBytes=" + droppedBytes + "]";
+    }
+}

src/main/java/org/apache/nifi/components/connector/components/ConnectionFacade.java

@@ -17,8 +17,13 @@
 
 package org.apache.nifi.components.connector.components;
 
+import org.apache.nifi.components.connector.DropFlowFileSummary;
 import org.apache.nifi.controller.queue.QueueSize;
 import org.apache.nifi.flow.VersionedConnection;
+import org.apache.nifi.flowfile.FlowFile;
+
+import java.io.IOException;
+import java.util.function.Predicate;
 
 public interface ConnectionFacade {
 
@@ -35,4 +40,13 @@ public interface ConnectionFacade {
      */
     void purge();
 
+    /**
+     * Drops all FlowFiles from the connection that match the given predicate.
+     *
+     * @param predicate the predicate to use to determine which FlowFiles to drop
+     * @return a summary of the FlowFiles that were dropped
+     * @throws IOException if an I/O error occurs while dropping FlowFiles
+     */
+    DropFlowFileSummary dropFlowFiles(Predicate<FlowFile> predicate) throws IOException;
+
 }

src/main/java/org/apache/nifi/components/connector/components/ProcessGroupFacade.java

@@ -17,10 +17,14 @@
 
 package org.apache.nifi.components.connector.components;
 
+import org.apache.nifi.components.connector.DropFlowFileSummary;
 import org.apache.nifi.controller.queue.QueueSize;
 import org.apache.nifi.flow.VersionedProcessGroup;
+import org.apache.nifi.flowfile.FlowFile;
 
+import java.io.IOException;
 import java.util.Set;
+import java.util.function.Predicate;
 
 public interface ProcessGroupFacade {
 
@@ -52,4 +56,14 @@ public interface ProcessGroupFacade {
 
     ProcessGroupLifecycle getLifecycle();
 
+    /**
+     * Drops all FlowFiles from all connections in this ProcessGroup and its child ProcessGroups
+     * that match the given predicate.
+     *
+     * @param predicate the predicate to test each FlowFile against
+     * @return a summary of the dropped FlowFiles
+     * @throws IOException if an I/O error occurs while dropping FlowFiles
+     */
+    DropFlowFileSummary dropFlowFiles(Predicate<FlowFile> predicate) throws IOException;
+
 }