org.argeo.util/src/org/argeo/util/LangUtils.java

   1 package org.argeo.util;
   2
   3 import java.io.IOException;
   4 import java.io.InputStream;
   5 import java.io.OutputStream;
   6 import java.nio.file.Files;
   7 import java.nio.file.Path;
   8 import java.util.Dictionary;
   9 import java.util.Enumeration;
  10 import java.util.Hashtable;
  11 import java.util.Map;
  12 import java.util.Properties;
  13
  14 public class LangUtils {
  15         /*
  16          * NON-API OSGi
  17          */
  18         /**
  19          * Returns an array with the names of the provided classes. Useful when
  20          * registering services with multiple interfaces in OSGi.
  21          */
  22         public static String[] names(Class<?>... clzz) {
  23                 String[] res = new String[clzz.length];
  24                 for (int i = 0; i < clzz.length; i++)
  25                         res[i] = clzz[i].getName();
  26                 return res;
  27         }
  28
  29         /*
  30          * DICTIONARY
  31          */
  32
  33         /**
  34          * Creates a new {@link Dictionary} with one key-value pair (neither key not
  35          * value should be null)
  36          */
  37         public static Dictionary<String, Object> init(String key, Object value) {
  38                 assert key != null;
  39                 assert value != null;
  40                 Hashtable<String, Object> props = new Hashtable<>();
  41                 props.put(key, value);
  42                 return props;
  43         }
  44
  45         /**
  46          * Wraps the keys of the provided {@link Dictionary} as an {@link Iterable}.
  47          */
  48         public static Iterable<String> keys(Dictionary<String, ?> props) {
  49                 assert props != null;
  50                 return new DictionaryKeys(props);
  51         }
  52
  53         public static String toJson(Dictionary<String, ?> props) {
  54                 return toJson(props, false);
  55         }
  56
  57         public static String toJson(Dictionary<String, ?> props, boolean pretty) {
  58                 StringBuilder sb = new StringBuilder();
  59                 sb.append('{');
  60                 if (pretty)
  61                         sb.append('\n');
  62                 Enumeration<String> keys = props.keys();
  63                 while (keys.hasMoreElements()) {
  64                         String key = keys.nextElement();
  65                         if (pretty)
  66                                 sb.append(' ');
  67                         sb.append('\"').append(key).append('\"');
  68                         if (pretty)
  69                                 sb.append(" : ");
  70                         else
  71                                 sb.append(':');
  72                         sb.append('\"').append(props.get(key)).append('\"');
  73                         if (keys.hasMoreElements())
  74                                 sb.append(", ");
  75                         if (pretty)
  76                                 sb.append('\n');
  77                 }
  78                 sb.append('}');
  79                 return sb.toString();
  80         }
  81
  82         public static void storeAsProperties(Dictionary<String, Object> props, Path path) throws IOException {
  83                 if (props == null)
  84                         throw new IllegalArgumentException("Props cannot be null");
  85                 Properties toStore = new Properties();
  86                 for (Enumeration<String> keys = props.keys(); keys.hasMoreElements();) {
  87                         String key = keys.nextElement();
  88                         toStore.setProperty(key, props.get(key).toString());
  89                 }
  90                 try (OutputStream out = Files.newOutputStream(path)) {
  91                         toStore.store(out, null);
  92                 }
  93         }
  94
  95         public static Dictionary<String, Object> loadFromProperties(Path path) throws IOException {
  96                 Properties toLoad = new Properties();
  97                 try (InputStream in = Files.newInputStream(path)) {
  98                         toLoad.load(in);
  99                 }
 100                 Dictionary<String, Object> res = new Hashtable<String, Object>();
 101                 for (Object key : toLoad.keySet())
 102                         res.put(key.toString(), toLoad.get(key));
 103                 return res;
 104         }
 105
 106         /** Singleton constructor. */
 107         private LangUtils() {
 108
 109         }
 110
 111 }