ContentUtils.java

   1 package org.argeo.api.gcr;
   2
   3 import java.io.PrintStream;
   4 import java.net.URI;
   5 import java.net.URISyntaxException;
   6 import java.util.Arrays;
   7 import java.util.Base64;
   8 import java.util.List;
   9 import java.util.function.BiConsumer;
  10
  11 public class ContentUtils {
  12         public static void traverse(Content content, BiConsumer<Content, Integer> doIt) {
  13                 traverse(content, doIt, 0);
  14         }
  15
  16         public static void traverse(Content content, BiConsumer<Content, Integer> doIt, int currentDepth) {
  17                 doIt.accept(content, currentDepth);
  18                 int nextDepth = currentDepth + 1;
  19                 for (Content child : content) {
  20                         traverse(child, doIt, nextDepth);
  21                 }
  22         }
  23
  24         public static void print(Content content, PrintStream out, int depth, boolean printText) {
  25                 StringBuilder sb = new StringBuilder();
  26                 for (int i = 0; i < depth; i++) {
  27                         sb.append("  ");
  28                 }
  29                 String prefix = sb.toString();
  30                 out.println(prefix + content.getName());
  31                 for (String key : content.keySet()) {
  32                         out.println(prefix + " " + key + "=" + content.get(key));
  33                 }
  34                 if (printText) {
  35                         if (content.hasText()) {
  36                                 out.println("<![CDATA[" + content.getText().trim() + "]]>");
  37                         }
  38                 }
  39         }
  40
  41         public static URI bytesToDataURI(byte[] arr) {
  42                 String base64Str = Base64.getEncoder().encodeToString(arr);
  43                 try {
  44                         final String PREFIX = "data:application/octet-stream;base64,";
  45                         return new URI(PREFIX + base64Str);
  46                 } catch (URISyntaxException e) {
  47                         throw new IllegalStateException("Cannot serialize bytes a Base64 data URI", e);
  48                 }
  49
  50         }
  51
  52         public static byte[] bytesFromDataURI(URI uri) {
  53                 if (!"data".equals(uri.getScheme()))
  54                         throw new IllegalArgumentException("URI must have 'data' as a scheme");
  55                 String schemeSpecificPart = uri.getSchemeSpecificPart();
  56                 int commaIndex = schemeSpecificPart.indexOf(',');
  57                 String prefix = schemeSpecificPart.substring(0, commaIndex);
  58                 List<String> info = Arrays.asList(prefix.split(";"));
  59                 if (!info.contains("base64"))
  60                         throw new IllegalArgumentException("URI must specify base64");
  61
  62                 String base64Str = uri.toString().substring(commaIndex);
  63                 return Base64.getDecoder().decode(base64Str);
  64
  65         }
  66
  67         public static <T> boolean isString(T t) {
  68                 return t instanceof String;
  69         }
  70
  71         /** Singleton. */
  72         private ContentUtils() {
  73
  74         }
  75 }