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.processors.barcode; 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.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicReference; import javax.imageio.ImageIO; import org.apache.commons.lang3.StringUtils; 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.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.InputStreamCallback; import org.apache.nifi.processor.io.StreamCallback; import com.google.zxing.BinaryBitmap; import com.google.zxing.DecodeHintType; import com.google.zxing.LuminanceSource; import com.google.zxing.MultiFormatReader; import com.google.zxing.Reader; import com.google.zxing.Result; import com.google.zxing.client.j2se.BufferedImageLuminanceSource; import com.google.zxing.common.HybridBinarizer; @Tags({ "barcode, scanner" }) @CapabilityDescription("Scans an image and searches for a barcode. The text of the found barcode is emitted by the processor.") @WritesAttributes({ @WritesAttribute(attribute = "barcode", description = "Barcode number pulled from the image"), }) public class BarcodeScannerProcessor extends AbstractProcessor { public static final String BARCODE_ATTRIBUTE_NAME = "barcode"; public static final String DESTINATION_ATTRIBUTE = "flowfile-attribute"; public static final String DESTINATION_CONTENT = "flowfile-content"; public static final PropertyDescriptor DESTINATION = new PropertyDescriptor.Builder().name("Destination") .description("Control if detected barcode value is written as a new flowfile attribute '" + BARCODE_ATTRIBUTE_NAME + "' " + "or written in the flowfile content. Writing to flowfile content will overwrite any " + "existing flowfile content.") .required(true).allowableValues(DESTINATION_ATTRIBUTE, DESTINATION_CONTENT) .defaultValue(DESTINATION_CONTENT).build(); public static final Relationship REL_SUCCESS = new Relationship.Builder().name("success") .description("Successfully found barcode").build(); public static final Relationship REL_FAILURE = new Relationship.Builder().name("failure") .description("Failed to obtain barcode from image").build(); private List<PropertyDescriptor> descriptors; private Set<Relationship> relationships; @Override protected void init(final ProcessorInitializationContext context) { final List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>(); descriptors.add(DESTINATION); this.descriptors = Collections.unmodifiableList(descriptors); final Set<Relationship> relationships = new HashSet<Relationship>(); relationships.add(REL_SUCCESS); relationships.add(REL_FAILURE); this.relationships = Collections.unmodifiableSet(relationships); } @Override public Set<Relationship> getRelationships() { return this.relationships; } @Override public final List<PropertyDescriptor> getSupportedPropertyDescriptors() { return descriptors; } @Override public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException { final FlowFile flowFile = session.get(); if (flowFile == null) { return; } final AtomicBoolean errors = new AtomicBoolean(false); switch (context.getProperty(DESTINATION).getValue()) { case DESTINATION_ATTRIBUTE: final AtomicReference<String> BC = new AtomicReference<>(); session.read(flowFile, new InputStreamCallback() { @Override public void process(InputStream inputStream) throws IOException { Map hintMap = new HashMap(); hintMap.put(DecodeHintType.TRY_HARDER, Boolean.TRUE); try { BufferedImage barCodeBufferedImage = ImageIO.read(inputStream); LuminanceSource source = new BufferedImageLuminanceSource(barCodeBufferedImage); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); Reader reader = new MultiFormatReader(); Result result = reader.decode(bitmap, hintMap); BC.set(result.getText()); } catch (Exception ex) { ex.printStackTrace(); //session.transfer(flowFile, REL_FAILURE); errors.set(true); } } }); if (StringUtils.isNotEmpty(BC.get())) { FlowFile atFlowFile = session.putAttribute(flowFile, BARCODE_ATTRIBUTE_NAME, BC.get()); if (!errors.get()) { session.transfer(atFlowFile, REL_SUCCESS); } else { session.transfer(atFlowFile, REL_FAILURE); } } else { if (!errors.get()) { session.transfer(flowFile, REL_SUCCESS); } else { session.transfer(flowFile, REL_FAILURE); } } break; case DESTINATION_CONTENT: FlowFile conFlowFile = session.write(flowFile, new StreamCallback() { @Override public void process(InputStream inputStream, OutputStream outputStream) throws IOException { Map hintMap = new HashMap(); hintMap.put(DecodeHintType.TRY_HARDER, Boolean.TRUE); try { BufferedImage barCodeBufferedImage = ImageIO.read(inputStream); LuminanceSource source = new BufferedImageLuminanceSource(barCodeBufferedImage); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); Reader reader = new MultiFormatReader(); Result result = reader.decode(bitmap, hintMap); getLogger().info("Barcode Format: " + result.getBarcodeFormat().toString()); getLogger().info("Barcode Text is: ' " + result.getText() + "'"); outputStream.write(result.getText().getBytes()); } catch (Exception ex) { ex.printStackTrace(); //session.transfer(flowFile, REL_FAILURE); errors.set(true); } } }); if (!errors.get()) { session.transfer(conFlowFile, REL_SUCCESS); } else { session.transfer(conFlowFile, REL_FAILURE); } break; } } }