Java tutorial
package com.zarkonnen.longan; /* * Copyright 2011 David Stark * * 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. */ import com.zarkonnen.longan.data.Result; import com.zarkonnen.longan.simple.SimpleWordPlaintextConverter; import com.zarkonnen.longan.stage.ResultConverter; import java.io.BufferedReader; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.HashMap; import javax.imageio.ImageIO; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; public class Main { static final String INVOCATION = "java -Xmx512m -jar longan.jar [OPTIONS] [INPUT FILE]"; static final ResultConverter<String> DEFAULT_FORMAT = new SimpleWordPlaintextConverter(); static final HashMap<String, ResultConverter> FORMATS = new HashMap<String, ResultConverter>(); static { FORMATS.put("plaintext", DEFAULT_FORMAT); FORMATS.put("visualize", new Visualizer()); } public static void main(String[] args) throws IOException { // Use Apache Commons CLI (packaged into the Jar) to parse command line options. Options options = new Options(); Option helpO = OptionBuilder.withDescription("print help").create("h"); Option versionO = OptionBuilder.withDescription("print version").create("v"); Option outputO = OptionBuilder.withDescription("output file").withLongOpt("out").hasArg() .withArgName("file").create("o"); Option formatO = OptionBuilder .withDescription("output format: one of plaintext (default) and visualize (debug output in png)") .hasArg().withArgName("format").withLongOpt("format").create(); Option serverO = OptionBuilder.withDescription("launches server mode: Server mode reads " + "command line strings one per line exactly as above. If no output file is " + "specified, returns a line containing the number of output lines before the " + "output. If there is an error, returns a single line with the error message. " + "Shut down server by sending \"quit\".").withLongOpt("server").create(); Option openCLO = OptionBuilder .withDescription( "enables use of the graphics card to " + "support the OCR system. Defaults to true.") .withLongOpt("enable-opencl").hasArg().withArgName("enabled").create(); options.addOption(helpO); options.addOption(versionO); options.addOption(outputO); options.addOption(formatO); options.addOption(serverO); options.addOption(openCLO); CommandLineParser clp = new GnuParser(); try { CommandLine line = clp.parse(options, args); if (line.hasOption("h")) { new HelpFormatter().printHelp(INVOCATION, options); System.exit(0); } if (line.hasOption("v")) { System.out.println(Longan.VERSION); System.exit(0); } boolean enableOpenCL = true; if (line.hasOption("enable-opencl")) { enableOpenCL = line.getOptionValue("enable-opencl").toLowerCase().equals("true") || line.getOptionValue("enable-opencl").equals("1"); } if (line.hasOption("server")) { Longan longan = Longan.getDefaultImplementation(enableOpenCL); BufferedReader inputR = new BufferedReader(new InputStreamReader(System.in)); while (true) { String input = inputR.readLine(); if (input.trim().equals("quit")) { return; } String[] args2 = splitInput(input); Options o2 = new Options(); o2.addOption(outputO); o2.addOption(formatO); try { line = clp.parse(o2, args2); File outFile = null; if (line.hasOption("o")) { outFile = new File(line.getOptionValue("o")); } ResultConverter format = FORMATS.get(line.getOptionValue("format", "plaintext")); if (format != DEFAULT_FORMAT && outFile == null) { System.out.println("You must specify an output file for non-plaintext output."); continue; } if (line.getArgList().isEmpty()) { System.out.println("Please specify an input image."); continue; } if (line.getArgList().size() > 1) { System.err.println("Please specify one input image at a time"); continue; } File inFile = new File((String) line.getArgList().get(0)); if (!inFile.exists()) { System.out.println("The input image does not exist."); continue; } try { Result result = longan.process(ImageIO.read(inFile)); if (outFile == null) { String txt = DEFAULT_FORMAT.convert(result); System.out.println(numNewlines(txt) + 1); System.out.print(txt); } else { if (outFile.getAbsoluteFile().getParentFile() != null && !outFile.getAbsoluteFile().getParentFile().exists()) { outFile.getParentFile().mkdirs(); } FileOutputStream fos = new FileOutputStream(outFile); try { format.write(result, fos); } finally { fos.close(); } } } catch (Exception e) { System.out.println("Processing error: " + exception(e)); } } catch (ParseException e) { System.out.println("Input not recognized: " + exception(e)); } } // End server loop } else { // Single invocation File outFile = null; if (line.hasOption("o")) { outFile = new File(line.getOptionValue("o")); } ResultConverter format = FORMATS.get(line.getOptionValue("format", "plaintext")); if (format != DEFAULT_FORMAT && outFile == null) { System.err.println("You must specify an output file for non-plaintext output."); System.exit(1); } if (line.getArgList().isEmpty()) { System.err.println("Please specify an input image."); new HelpFormatter().printHelp(INVOCATION, options); System.exit(1); } if (line.getArgList().size() > 1) { System.err.println("Please specify one input image only. To process multiple " + "images, use server mode."); System.exit(1); } File inFile = new File((String) line.getArgList().get(0)); if (!inFile.exists()) { System.err.println("The input image does not exist."); System.exit(1); } try { Result result = Longan.getDefaultImplementation(enableOpenCL).process(ImageIO.read(inFile)); if (outFile == null) { String txt = DEFAULT_FORMAT.convert(result); System.out.print(txt); } else { if (outFile.getAbsoluteFile().getParentFile() != null && !outFile.getAbsoluteFile().getParentFile().exists()) { outFile.getParentFile().mkdirs(); } FileOutputStream fos = new FileOutputStream(outFile); try { format.write(format.convert(result), fos); } finally { fos.close(); } } } catch (Exception e) { System.err.println("Processing error: " + exception(e)); System.exit(1); } } } catch (ParseException e) { System.err.println("Parsing command line input failed: " + exception(e)); System.exit(1); } } static int numNewlines(String str) { int n = 0; for (int i = 0; i < str.length(); i++) { n += str.charAt(i) == '\n' ? 1 : 0; } return n; } /** Splits an input string in the same way as the shell does. */ static String[] splitInput(String input) { StringBuilder b = new StringBuilder(); ArrayList<String> args = new ArrayList<String>(); boolean singleQuoted = false; boolean doubleQuoted = false; boolean escaped = false; for (int i = 0; i < input.length(); i++) { char c = input.charAt(i); if (escaped) { b.append(c); escaped = false; } else if ((singleQuoted && c != '\'') || (doubleQuoted && c == '\'')) { b.append(c); } else { switch (c) { case '\\': escaped = true; break; case '\"': doubleQuoted = !doubleQuoted; break; case '\'': singleQuoted = !singleQuoted; break; case ' ': if (singleQuoted || doubleQuoted) { b.append(c); } else { if (b.length() > 0) { args.add(b.toString()); b = new StringBuilder(); } } break; default: b.append(c); break; } } } if (doubleQuoted) { throw new RuntimeException("Mismatched quotes in input."); } if (b.length() > 0) { args.add(b.toString()); } return args.toArray(new String[args.size()]); } static String exception(Exception e) { e.printStackTrace(); return e.getMessage() == null ? e.getClass().getName() : e.getMessage().replace("\n", " ").replace("\r", " "); } }