Implemented a new syntax in the template engine to simplify json APIs

Added also an example for one of the existing APIs. The problem is the
comma separator between objects which must not be there for the last
entry in a sequence. The new syntax adds the separator symbol
automatically.

htroot/api/linkstructure.java

@@ -107,10 +107,8 @@ public class linkstructure {
             Integer depth_target = hlg.getDepth(e.target);
             prop.put("edges_" + c + "_depthSource", depth_source == null ? -1 : depth_source.intValue());
             prop.put("edges_" + c + "_depthTarget", depth_target == null ? -1 : depth_target.intValue());
-            prop.put("edges_" + c + "_eol", 1);
             c++;
         }
-        prop.put("edges_" + (c-1) + "_eol", 0);
         prop.put("edges", c);
         prop.put("maxdepth", maxdepth);
     }

htroot/api/linkstructure.json

@@ -1,7 +1,7 @@
 {
 "edges" : "#[edges]#",
 "maxdepth" : "#[maxdepth]#",
-"graph" : [#{edges}#
+"graph" : [#{edges|,}#
-{"source":"#[source]#", "target":"#[target]#", "type":"#[type]#", "depthSource":"#[depthSource]#", "depthTarget":"#[depthTarget]#"}#(eol)#::,#(/eol)#
+{"source":"#[source]#", "target":"#[target]#", "type":"#[type]#", "depthSource":"#[depthSource]#", "depthTarget":"#[depthTarget]#"}
 #{/edges}#]
 }

source/net/yacy/server/http/TemplateEngine.java

@@ -229,6 +229,15 @@ public final class TemplateEngine {
                     multi_key = keyStream.toByteArray(); //IMPORTANT: no prefix here
                     keyStream.reset(); //reset stream
 
+                    // read a separator character
+                    byte sep_char = -1;
+                    if (multi_key.length > 3 && multi_key[multi_key.length - 2] == '|') {
+                        sep_char = multi_key[multi_key.length - 1];
+                        byte[] a = new byte[multi_key.length - 2];
+                        System.arraycopy(multi_key, 0, a, 0, multi_key.length - 2);
+                        multi_key = a;
+                    }
+
                     //this needs multi_key without prefix
                     if (transferUntil(pis, keyStream, appendBytes(mOpen, slashChar, multi_key, mClose))){
                         bb = pis.read();
@@ -237,6 +246,24 @@ public final class TemplateEngine {
                         }
 
                         final byte[] text=keyStream.toByteArray(); //text between #{key}# an #{/key}#
+                        byte[] textsep = text;
+                        int p = text.length;
+                        if (sep_char != -1) {
+                            byte[] a = new byte[p + 1];
+                            System.arraycopy(text, 0, a, 0, p);
+                            // put the separator in front of a cr/lb
+                            if (p >= 2 && a[p - 1] < 32 && a[p - 2] < 32) { // cr and lf
+                                a[p] = a[p - 1];
+                                a[p - 1] = a[p - 2];
+                                a[p - 2] = sep_char;
+                            } else if (p >= 1 && a[p - 1] < 32) { // cr or lf
+                                a[p] = a[p - 1];
+                                a[p - 1] = sep_char;
+                            } else {
+                                a[p] = sep_char;
+                            }
+                            textsep = a;
+                        }
                         int num=0;
                         final String patternKey = getPatternKey(prefix, multi_key);
                         if(pattern.containsKey(patternKey) && !pattern.get(patternKey).isEmpty()){
@@ -254,7 +281,7 @@ public final class TemplateEngine {
                                  .append(ASCII.getBytes(Integer.toString(num)))
                                  .append(close_quotetagn);
                         for(int i=0;i < num;i++) {
-                            final PushbackInputStream pis2 = new PushbackInputStream(new ByteArrayInputStream(text));
+                            final PushbackInputStream pis2 = new PushbackInputStream(new ByteArrayInputStream(sep_char != -1 && i < num -1 ? textsep : text));
                             //System.out.println("recursing with text(prefix="+ multi_key + "_" + i + "_" +"):"); //DEBUG
                             //System.out.println(text);
                             structure.append(writeTemplate(servletname, pis2, out, pattern, newPrefix(prefix,multi_key,i)));