Java tutorial
/* * 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 com.jeremydyer.nifi; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Set; import javax.imageio.ImageIO; import org.apache.nifi.annotation.behavior.WritesAttribute; import org.apache.nifi.annotation.behavior.WritesAttributes; import org.apache.nifi.annotation.documentation.CapabilityDescription; import org.apache.nifi.annotation.documentation.Tags; import org.apache.nifi.annotation.lifecycle.OnScheduled; import org.apache.nifi.components.PropertyDescriptor; import org.apache.nifi.flowfile.FlowFile; import org.apache.nifi.processor.AbstractProcessor; import org.apache.nifi.processor.ProcessContext; import org.apache.nifi.processor.ProcessSession; import org.apache.nifi.processor.ProcessorInitializationContext; import org.apache.nifi.processor.Relationship; import org.apache.nifi.processor.exception.ProcessException; import org.apache.nifi.processor.io.OutputStreamCallback; import org.apache.nifi.processor.util.StandardValidators; import org.apache.nifi.stream.io.ByteArrayInputStream; import org.opencv.core.Core; import org.opencv.core.MatOfByte; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.videoio.VideoCapture; import org.opencv.videoio.Videoio; @Tags({ "image" }) @CapabilityDescription("Extract a frame from the camera") @WritesAttributes({ @WritesAttribute(attribute = "", description = "") }) public class GetCameraFrame extends AbstractProcessor { public static final PropertyDescriptor CAMERA = new PropertyDescriptor.Builder().name("Camera") .description("Camera Device Identifier").required(true) .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); public static final Relationship REL_SUCCESS = new Relationship.Builder().name("success") .description("FlowFiles are generated from image frames").build(); public static final PropertyDescriptor FRAME_WIDTH = new PropertyDescriptor.Builder().name("Width") .description("Width in pixels of capture").required(false).defaultValue("1280") .addValidator(StandardValidators.INTEGER_VALIDATOR).build(); public static final PropertyDescriptor FRAME_HEIGHT = new PropertyDescriptor.Builder().name("Height") .description("Height in pixels of capture").required(false).defaultValue("720") .addValidator(StandardValidators.INTEGER_VALIDATOR).build(); private List<PropertyDescriptor> descriptors; private Set<Relationship> relationships; private VideoCapture camera; private final int CAMERA_ID = 0; @Override protected void init(final ProcessorInitializationContext context) { final List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>(); //descriptors.add(CAMERA); descriptors.add(FRAME_WIDTH); descriptors.add(FRAME_HEIGHT); this.descriptors = Collections.unmodifiableList(descriptors); final Set<Relationship> relationships = new HashSet<Relationship>(); relationships.add(REL_SUCCESS); this.relationships = Collections.unmodifiableSet(relationships); System.loadLibrary(Core.NATIVE_LIBRARY_NAME); camera = new VideoCapture(CAMERA_ID); try { Thread.sleep(2000); //Give the Camera a few seconds to initialize } catch (InterruptedException e) { e.printStackTrace(); } camera.open(CAMERA_ID); if (!camera.isOpened()) { getLogger().error("Camera Error"); } else { getLogger().error("Camera OK?"); } } @Override public Set<Relationship> getRelationships() { return this.relationships; } @Override public final List<PropertyDescriptor> getSupportedPropertyDescriptors() { return descriptors; } @OnScheduled public void onScheduled(final ProcessContext context) { double width = context.getProperty(FRAME_WIDTH).asDouble().doubleValue(); camera.set(Videoio.CV_CAP_PROP_FRAME_WIDTH, width); double height = context.getProperty(FRAME_HEIGHT).asDouble().doubleValue(); camera.set(Videoio.CV_CAP_PROP_FRAME_HEIGHT, height); } @Override public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException { MatOfByte image = new MatOfByte(); MatOfByte bytemat = new MatOfByte(); camera.read(image); Imgcodecs.imencode(".png", image, bytemat); byte[] bytes = bytemat.toArray(); InputStream in = new ByteArrayInputStream(bytes); try { final BufferedImage img = ImageIO.read(in); FlowFile flowFile = session.create(); flowFile = session.write(flowFile, new OutputStreamCallback() { @Override public void process(final OutputStream out) throws IOException { ImageIO.write(img, "PNG", out); } }); session.getProvenanceReporter().create(flowFile); session.transfer(flowFile, REL_SUCCESS); } catch (IOException e) { } } }