add JRuby-JDOM backend for XmlMini

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

1 files changed, 162 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/xml_mini/jdom.rb b/activesupport/lib/active_support/xml_mini/jdom.rb
new file mode 100644
index 0000000000..d795d55690
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/jdom.rb
@@ -0,0 +1,162 @@
+raise "JRuby is required to use the JDOM backend for XmlMini" unless RUBY_PLATFORM =~ /java/
+
+require 'jruby'
+include Java
+
+import javax.xml.parsers.DocumentBuilder unless defined? DocumentBuilder
+import javax.xml.parsers.DocumentBuilderFactory unless defined? DocumentBuilderFactory
+import java.io.StringReader unless defined? StringReader
+import org.xml.sax.InputSource unless defined? InputSource
+import org.xml.sax.Attributes unless defined? Attributes
+import org.w3c.dom.Node unless defined? Node
+
+# = XmlMini JRuby JDOM implementation
+module ActiveSupport
+  module XmlMini_JDOM #:nodoc:
+    extend self
+
+    CONTENT_KEY = '__content__'.freeze
+
+    NODE_TYPE_NAMES = %w{ATTRIBUTE_NODE CDATA_SECTION_NODE COMMENT_NODE DOCUMENT_FRAGMENT_NODE
+    DOCUMENT_NODE DOCUMENT_TYPE_NODE ELEMENT_NODE ENTITY_NODE ENTITY_REFERENCE_NODE NOTATION_NODE
+    PROCESSING_INSTRUCTION_NODE TEXT_NODE}
+
+    node_type_map = {}
+    NODE_TYPE_NAMES.each { |type| node_type_map[Node.send(type)] = type }
+
+    # Parse an XML Document string into a simple hash using Java's jdom.
+    # string::
+    #   XML Document string to parse
+    def parse(string)
+      if string.blank?
+        {}
+      else
+        @dbf = DocumentBuilderFactory.new_instance
+        xml_string_reader = StringReader.new(string)
+        xml_input_source = InputSource.new(xml_string_reader)
+        doc = @dbf.new_document_builder.parse(xml_input_source)
+        merge_element!({}, doc.document_element)
+      end
+    end
+
+    private
+
+    # Convert an XML element and merge into the hash
+    #
+    # hash::
+    #   Hash to merge the converted element into.
+    # element::
+    #   XML element to merge into hash
+    def merge_element!(hash, element)
+      merge!(hash, element.tag_name, collapse(element))
+    end
+
+    # Actually converts an XML document element into a data structure.
+    #
+    # element::
+    #   The document element to be collapsed.
+    def collapse(element)
+      hash = get_attributes(element)
+
+      child_nodes = element.child_nodes
+      if child_nodes.length > 0
+        for i in 0...child_nodes.length
+          child = child_nodes.item(i)
+          merge_element!(hash, child) unless child.node_type == Node.TEXT_NODE
+        end
+        merge_texts!(hash, element) unless empty_content?(element)
+        hash
+      else
+        merge_texts!(hash, element)
+      end
+    end
+
+    # Merge all the texts of an element into the hash
+    #
+    # hash::
+    #   Hash to add the converted emement to.
+    # element::
+    #   XML element whose texts are to me merged into the hash
+    def merge_texts!(hash, element)
+      text_children = texts(element)
+      if text_children.join.empty?
+        hash
+      else
+        # must use value to prevent double-escaping
+        merge!(hash, CONTENT_KEY, text_children.join)
+      end
+    end
+
+    # Adds a new key/value pair to an existing Hash. If the key to be added
+    # already exists and the existing value associated with key is not
+    # an Array, it will be wrapped in an Array. Then the new value is
+    # appended to that Array.
+    #
+    # hash::
+    #   Hash to add key/value pair to.
+    # key::
+    #   Key to be added.
+    # value::
+    #   Value to be associated with key.
+    def merge!(hash, key, value)
+      if hash.has_key?(key)
+        if hash[key].instance_of?(Array)
+          hash[key] << value
+        else
+          hash[key] = [hash[key], value]
+        end
+      elsif value.instance_of?(Array)
+        hash[key] = [value]
+      else
+        hash[key] = value
+      end
+      hash
+    end
+
+    # Converts the attributes array of an XML element into a hash.
+    # Returns an empty Hash if node has no attributes.
+    #
+    # element::
+    #   XML element to extract attributes from.
+    def get_attributes(element)
+      attribute_hash = {}
+      attributes = element.attributes
+      for i in 0...attributes.length
+         attribute_hash[attributes.item(i).name] =  attributes.item(i).value
+       end
+      attribute_hash
+    end
+
+    # Determines if a document element has text content
+    #
+    # element::
+    #   XML element to be checked.
+    def texts(element)
+      texts = []
+      child_nodes = element.child_nodes
+      for i in 0...child_nodes.length
+        item = child_nodes.item(i)
+        if item.node_type == Node.TEXT_NODE
+          texts << item.get_data
+        end
+      end
+      texts
+    end
+
+    # Determines if a document element has text content
+    #
+    # element::
+    #   XML element to be checked.
+    def empty_content?(element)
+      text = ''
+      child_nodes = element.child_nodes
+      for i in 0...child_nodes.length
+        item = child_nodes.item(i)
+        if item.node_type == Node.TEXT_NODE
+          text << item.get_data.strip
+        end
+      end
+      text.strip.length == 0
+    end
+  end
+end