Java tutorial
/* $Id$ Copyright (C) 2003-2012 Virginia Tech. All rights reserved. SEE LICENSE FOR MORE INFORMATION Author: Middleware Services Email: middleware@vt.edu Version: $Revision$ Updated: $Date$ */ package edu.vt.middleware.ldap.cli; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.HashMap; import java.util.Map; import java.util.Properties; import edu.vt.middleware.ldap.ConnectionFactory; import edu.vt.middleware.ldap.Credential; import edu.vt.middleware.ldap.DefaultConnectionFactory; import edu.vt.middleware.ldap.props.DefaultConnectionFactoryPropertySource; import edu.vt.middleware.ldap.props.PropertySource.PropertyDomain; 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.Options; import org.apache.commons.cli.ParseException; /** * Abstract base class for all CLI classes. * * @author Middleware Services * @version $Revision$ */ public abstract class AbstractCli { /** option to print usage. */ protected static final String OPT_HELP = "help"; /** option for provider properties. */ protected static final String OPT_PROVIDER_PROPERTIES = "providerProperties"; /** command line options. */ protected Options options = new Options(); /** whether to output dsml version 1, the default is ldif. */ protected boolean outputDsmlv1; /** * Parses command line options and dispatches to the requested action, or the * default action if no action is specified. * * @param args command line arguments */ public final void performAction(final String[] args) { initOptions(); try { if (args.length > 0) { final CommandLineParser parser = new GnuParser(); final CommandLine line = parser.parse(options, args, false); dispatch(line); } else { printExamples(); } } catch (ParseException pex) { System.err.println("Failed parsing command arguments: " + pex.getMessage()); } catch (IllegalArgumentException iaex) { String msg = "Operation failed: " + iaex.getMessage(); if (iaex.getCause() != null) { msg += " Underlying reason: " + iaex.getCause().getMessage(); } System.err.println(msg); } catch (RuntimeException rex) { throw rex; } catch (Exception ex) { System.err.println("Operation failed:"); ex.printStackTrace(System.err); } } /** Initialize CLI options. */ protected void initOptions() { options.addOption(new Option(OPT_HELP, false, "display all options")); } /** * Initialize a connection factory with command line options. * * @param line parsed command line arguments * * @return connection factory that has been initialized * * @throws Exception if a connection config cannot be created */ protected ConnectionFactory initConnectionFactory(final CommandLine line) throws Exception { final DefaultConnectionFactory factory = new DefaultConnectionFactory(); final DefaultConnectionFactoryPropertySource cfSource = new DefaultConnectionFactoryPropertySource(factory, getPropertiesFromOptions(PropertyDomain.LDAP.value(), line)); cfSource.initialize(); if (factory.getConnectionConfig().getBindDn() != null && factory.getConnectionConfig().getBindCredential() == null) { // prompt the user to enter a password final char[] pass = System.console().readPassword("[Enter password for %s]: ", factory.getConnectionConfig().getBindDn()); factory.getConnectionConfig().setBindCredential(new Credential(pass)); } return factory; } /** * Returns the name of the command for which this class provides a CLI * interface. * * @return name of CLI command */ protected abstract String getCommandName(); /** * Dispatch command line data to the active that can perform the operation * requested on the command line. * * @param line parsed command line arguments * * @throws Exception on errors thrown by action */ protected abstract void dispatch(final CommandLine line) throws Exception; /** Prints CLI help text. */ protected void printHelp() { final HelpFormatter formatter = new HelpFormatter(); formatter.printHelp(getCommandName(), options); } /** Prints CLI usage examples. */ protected void printExamples() { final String name = getClass().getSimpleName(); final InputStream in = getClass().getResourceAsStream(name + ".examples"); if (in != null) { final BufferedReader reader = new BufferedReader(new InputStreamReader(in)); try { System.out.println(); String line = null; while ((line = reader.readLine()) != null) { System.out.println(line); } } catch (IOException e) { System.err.println("Error reading examples from resource stream."); } finally { try { reader.close(); } catch (IOException ex) { System.err.println("Error closing example resource stream."); } System.out.println(); } } else { System.out.println("No usage examples available for " + getCommandName()); } } /** * Returns the command line argument descriptions for this CLI. * * @param classes that contain arguments used by this CLI * * @return map of argument name to description */ protected Map<String, String> getArgDesc(final Class<?>... classes) { final Map<String, String> args = new HashMap<String, String>(); for (Class<?> c : classes) { final String name = c.getSimpleName(); final InputStream in = getClass().getResourceAsStream(name + ".args"); if (in != null) { final BufferedReader reader = new BufferedReader(new InputStreamReader(in)); try { String line = null; while ((line = reader.readLine()) != null) { final String[] s = line.split(":"); if (s.length > 1) { args.put(s[0], s[1]); } } } catch (IOException e) { System.err.println("Error reading arguments from resource stream."); } finally { try { reader.close(); } catch (IOException ex) { System.err.println("Error closing arguments resource stream."); } } } } if (args.isEmpty()) { System.err.println("No arguments available for " + getCommandName()); } return args; } /** * Reads the options from the supplied command line and returns a properties * containing those options. * * @param domain to place property names in * @param line command line * * @return properties for each option and value */ protected Properties getPropertiesFromOptions(final String domain, final CommandLine line) { final Properties props = new Properties(); for (Option o : line.getOptions()) { if (o.hasArg()) { // if provider property, split the value if (o.getOpt().equals(OPT_PROVIDER_PROPERTIES)) { final String[] s = o.getValue().split("="); props.setProperty(s[0], s[1]); // add the domain to vt-ldap properties } else { props.setProperty(domain + o.getOpt(), o.getValue()); } } } return props; } }