[Practicalxml-commits] SF.net SVN: practicalxml:[144] branches/dev-1.1/src

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Revision: 144
          http://practicalxml.svn.sourceforge.net/practicalxml/?rev=144&view=rev
Author:   kdgregory
Date:     2009-09-22 17:32:02 +0000 (Tue, 22 Sep 2009)

Log Message:
-----------
xml->json: support arrays

Modified Paths:
--------------
    branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/Xml2JsonConverter.java
    branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/package.html
    branches/dev-1.1/src/test/java/net/sf/practicalxml/converter/json/TestXml2JsonConverter.java

Modified: branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/Xml2JsonConverter.java
===================================================================

--- branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/Xml2JsonConverter.java	2009-09-22 15:27:06 UTC (rev 143)
+++ branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/Xml2JsonConverter.java	2009-09-22 17:32:02 UTC (rev 144)
@@ -14,9 +14,12 @@
 
 package net.sf.practicalxml.converter.json;
 
+import java.util.ArrayList;
 import java.util.EnumSet;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 
 import net.sf.practicalxml.DomUtil;
 
@@ -43,16 +46,24 @@
 //----------------------------------------------------------------------------
 
     /**
-     *  Appends the contents of the specified element to an existing buffer.
+     *  Converts the subtree rooted at <code>elem</code> to a JSON string.
+     */
+    public String convert(Element elem)
+    {
+        return convert(elem, new StringBuilder(256)).toString();
+    }
+
+
+    /**
+     *  Converts the subtree rooted at <code>elem</code> to a JSON string,
+     *  appending to an existing buffer. This is useful when building a
+     *  JSON assignment statment (eg: "var x = OBJECT").
+     *  <p>
      *  Returns the buffer as a convenience.
      */
     public StringBuilder convert(Element elem, StringBuilder buf)
     {
-        String text = DomUtil.getText(elem);
-        if (text != null)
-            return appendText(text, buf);
-        else
-            return appendChildren(elem, buf);
+        return append(buf, elem);
     }
 
 
@@ -60,8 +71,22 @@
 //  Internals
 //----------------------------------------------------------------------------
 
-    private StringBuilder appendText(String text, StringBuilder buf)
+    // yes, this method is just a restatement of convert(Element,StringBuilder)
+    // I want all the internal appenders named "append".
+    private StringBuilder append(StringBuilder buf, Element elem)
     {
+        List<Element> children = DomUtil.getChildren(elem);
+        String text = DomUtil.getText(elem);
+
+        if ((children.size() > 0) || (text == null))
+            return appendObject(buf, children);
+        else
+            return appendText(buf, text);
+    }
+
+
+    private StringBuilder appendText(StringBuilder buf, String text)
+    {
         buf.append('"')
            .append(JsonUtil.escape(text))
            .append('"');
@@ -69,20 +94,74 @@
     }
 
 
-    private StringBuilder appendChildren(Element elem, StringBuilder buf)
+    private StringBuilder appendObject(StringBuilder buf,  List<Element> children)
     {
+        List<String> names = new ArrayList<String>();
+        Map<String,List<Element>> arrays = new HashMap<String,List<Element>>();
+        Map<String,Element> nonArrays = new HashMap<String,Element>();
+        categorizeChildren(children, names, arrays, nonArrays);
+
         buf.append("{");
-        List<Element> children = DomUtil.getChildren(elem);
-        for (Iterator<Element> childItx = children.iterator() ; childItx.hasNext() ; )
+        for (Iterator<String> itx = names.iterator() ; itx.hasNext() ; )
         {
-            Element child = childItx.next();
-            buf.append(DomUtil.getLocalName(child))
-               .append(": ");
-            convert(child, buf);
-            if (childItx.hasNext())
+            String name = itx.next();
+            buf.append(name).append(": ");
+            if (arrays.containsKey(name))
+                appendArray(buf, arrays.get(name));
+            else
+                append(buf, nonArrays.get(name));
+            if (itx.hasNext())
                 buf.append(", ");
         }
         buf.append("}");
         return buf;
     }
+
+
+    private StringBuilder appendArray(StringBuilder buf, List<Element> values)
+    {
+        buf.append("[");
+        for (Iterator<Element> itx = values.iterator() ; itx.hasNext() ; )
+        {
+            Element child = itx.next();
+            append(buf, child);
+            if (itx.hasNext())
+                buf.append(", ");
+        }
+        buf.append("]");
+        return buf;
+    }
+
+
+    /**
+     *  Examines the children of the passed element and categorizes them as
+     *  "array" or "not array", while tracking the first appearance of the
+     *  element name in document order.
+     */
+    private void categorizeChildren(
+            List<Element> children, List<String> names,
+            Map<String,List<Element>> arrays, Map<String,Element> nonArrays)
+    {
+        for (Element child : children)
+        {
+            String name = DomUtil.getLocalName(child);
+            if (arrays.containsKey(name))
+            {
+                arrays.get(name).add(child);
+            }
+            else if (nonArrays.containsKey(name))
+            {
+                Element prev = nonArrays.remove(name);
+                List<Element> list = new ArrayList<Element>(2);
+                list.add(prev);
+                list.add(child);
+                arrays.put(name, list);
+            }
+            else
+            {
+                nonArrays.put(name, child);
+                names.add(name);
+            }
+        }
+    }
 }

Modified: branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/package.html
===================================================================
--- branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/package.html	2009-09-22 15:27:06 UTC (rev 143)
+++ branches/dev-1.1/src/main/java/net/sf/practicalxml/converter/json/package.html	2009-09-22 17:32:02 UTC (rev 144)
@@ -2,36 +2,39 @@
 <body>
 
 This package contains classes to convert JSON (JavaScript Object Notation)
-strings (as defined <a href="http://www.json.org/">json.org</a> ) to and 
+strings (as defined <a href="http://www.json.org/">json.org</a> ) to and
 from an XML DOM. Although both XML and JSON are textual representations of
 hierarchical data, there are some peculiarities in the conversion:
 
 <dl>
 <dt> Container Element
 <dd> Although elements within a JSON object are named, the object itself is
-	 not. XML requires a named root element, so the JSON->XML conversion
-	 creates a root element named "data", and the XML->JSON conversion ignores
-	 the passed root element.
+	 not. XML requires a named root element, so the JSON to XML conversion
+	 creates a root element named "data", and the XML to JSON conversion
+	 ignores the passed root element.
 <dt> Document Order
 <dd> In XML, document order is important and may be validated; in JSON, the
 	 order of elements within an object is not important. To support arrays
-	 (qv), the XML->JSON conversion intentionally breaks document order. And
+	 the XML to JSON conversion intentionally breaks document order (qv). And
 	 as JSON has no intrinsic order, you'll need to explicitly re-arrange the
-	 result of a JSON->XML conversion prior to any validation.	 	
+	 result of a JSON to XML conversion prior to any validation.	 	
 <dt> Non-String Data
 <dd> JSON supports numbers and boolean literals in addition to quote-delimited
-	 strings. The JSON->XML conversion will handle these values transparently.
-	 The default XML->JSON conversion writes all content as quote-delimited 
+	 strings. The JSON to XML conversion will handle these values transparently.
+	 The default XML to JSON conversion writes all content as quote-delimited
 	 strings, but there is a conversion option to recognize a limited set of
-	 non-string elements based on the <code>xsi:type</code> attribute.	 
-<dt> Arrays
+	 non-string elements based on the <code>xsi:type</code> attribute.	
+<dt> Arrays, XML to JSON
 <dd> XML does not have a defined array construct, but may repeat elements; JSON
 	 has a defined array construct, and repeated elements will overwrite the
-	 former definition. To avoid this problem, the XML->JSON conversion will
-	 identify all repeated elements and create an array construct. The default
-	 JSON->XML conversion creates a parent-children construct (which is more
-	 palatable to subsequent XML->Java conversion), but a conversion option
-	 allows conversion to a repeated element.
+	 former definition. To avoid this problem, the XML to JSON converter will
+	 create a JSON array construct from all siblings with the same localname.
+<dt> Arrays, JSON to XML
+<dd> By default, arrays are converted into a single parent element, with one
+	 child named "data" for each element of the array; this is similar to the
+	 Java to XML conversion. Optionally, you may convert an array into a series
+	 of repeated elements (siblings), all with the same name. When using this
+	 option, conversion will fail if presented with a top-level JSON array.
 </dl>
 
 </body>

Modified: branches/dev-1.1/src/test/java/net/sf/practicalxml/converter/json/TestXml2JsonConverter.java
===================================================================
--- branches/dev-1.1/src/test/java/net/sf/practicalxml/converter/json/TestXml2JsonConverter.java	2009-09-22 15:27:06 UTC (rev 143)
+++ branches/dev-1.1/src/test/java/net/sf/practicalxml/converter/json/TestXml2JsonConverter.java	2009-09-22 17:32:02 UTC (rev 144)
@@ -37,9 +37,8 @@
     public void convertAndAssert(String expected, ElementNode rootNode)
     {
         Element root = rootNode.toDOM().getDocumentElement();
-        StringBuilder buf = new Xml2JsonConverter()
-                           .convert(root, new StringBuilder(256));
-        assertEquals(expected, buf.toString());
+        String json = new Xml2JsonConverter().convert(root);
+        assertEquals(expected, json);
     }
 
 
@@ -86,6 +85,53 @@
     }
 
 
+    public void testArray() throws Exception
+    {
+        // note that "argle" elements are not adjacent, must become adjacent
+        convertAndAssert(
+                "{foo: \"bar\", argle: [\"bargle\", \"wargle\"], baz: \"bar\"}",
+                element("data",
+                    element("foo", text("bar")),
+                    element("argle", text("bargle")),
+                    element("baz", text("bar")),
+                    element("argle", text("wargle"))));
+    }
+
+
+    public void testArrayWithNestedObject() throws Exception
+    {
+        convertAndAssert(
+                "{foo: \"bar\", argle: [\"bargle\", {foo: \"bar\", bar: \"baz\"}]}",
+                element("data",
+                    element("foo", text("bar")),
+                    element("argle", text("bargle")),
+                    element("argle",
+                            element("foo", text("bar")),
+                            element("bar", text("baz")))));
+    }
+
+
+    // this covers documents parsed with "ignorable whitespace"
+    public void testMixedContentWithWhitespace() throws Exception
+    {
+        convertAndAssert(
+                "{foo: \"bar\"}",
+                element("data",
+                    text("    "),
+                    element("foo", text("bar")),
+                    text("\n")));
+    }
+
+
+    public void testWhitespace() throws Exception
+    {
+        convertAndAssert(
+                "{foo: \"   \"}",
+                element("data",
+                    element("foo", text("   "))));
+    }
+
+
     public void testStringEscaping() throws Exception
     {
         convertAndAssert(


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