XMLParserin optimointi

src/main/kotlin/DictionaryParser.kt

 package guru.kake.ronove
 
 import java.io.FileInputStream
+import javax.xml.namespace.QName
 import javax.xml.stream.XMLEventReader
 import javax.xml.stream.XMLInputFactory
 import javax.xml.stream.events.XMLEvent

src/main/kotlin/XMLParser.kt

@@ -18,20 +18,31 @@ class XMLParser private constructor(path: String) {
         /**
          * Parse an XML-file using an event-based interface
          * @param path path to file
-         * @param loop lambda to execute on each XML event
+         * @param init lambda to execute on each XML event
          */
-        fun parse(path: String, loop: XMLParser.() -> Unit) = XMLParser(path).init(loop)
+        fun parse(path: String, init: XMLParser.() -> Unit) = XMLParser(path).init(init)
     }
 
     private val factory: XMLInputFactory = XMLInputFactory.newInstance()
     private val reader: XMLEventReader = factory.createXMLEventReader(FileInputStream(path))
-    private var event: XMLEvent? = null
+    private val elements: MutableMap<String, Element> = mutableMapOf()
 
-    private fun init(loop: XMLParser.() -> Unit) {
+    private fun init(init: XMLParser.() -> Unit) {
+        @Suppress("UNUSED_EXPRESSION") // IntelliJ IDEA bug: https://youtrack.jetbrains.com/issue/KT-21282
+        init()
         while (reader.hasNext()) {
-            event = reader.nextEvent()
-            @Suppress("UNUSED_EXPRESSION") // IntelliJ IDEA bug: https://youtrack.jetbrains.com/issue/KT-21282
-            loop()
+            parse(reader.nextEvent())
+        }
+    }
+
+    private fun parse(event: XMLEvent) {
+        when {
+            event.isStartElement -> {
+                elements[event.asStartElement().name.localPart.toString()]?.parseStart(event)
+            }
+            event.isEndElement -> {
+                elements[event.asEndElement().name.localPart.toString()]?.parseEnd()
+            }
         }
     }
 
@@ -40,17 +51,29 @@ class XMLParser private constructor(path: String) {
      * @param name Element name
      * @param f code to execute on elements matching name
      */
-    fun element(name: String, f: Element.() -> Unit) = Element(name, reader, event!!).f()
+    fun element(name: String, f: Element.() -> Unit) {
+        elements[name] = Element(reader).also { it.f() }
+    }
 
     @DSL
-    inner class Element(private val name: String, private val reader: XMLEventReader, private val event: XMLEvent) {
+    inner class Element(private val reader: XMLEventReader) {
+        private var startFunc: (() -> Unit)? = null
+        private var endFunc: (() -> Unit)? = null
+        private var event: XMLEvent? = null
+
+        internal fun parseStart(event: XMLEvent) {
+            this.event = event
+            startFunc?.invoke()
+        }
+
+        internal fun parseEnd() { endFunc?.invoke() }
+
         /**
          * Specify code to execute when encountering a starting tag of the specified element
          * @param f code to execute
          */
-        fun start(f: StartElement.() -> Unit) {
-            if (event.isStartElement && event.asStartElement().name.localPart.toString() == name)
-                StartElement(reader, event.asStartElement()).f()
+        fun start(f: () -> Unit) {
+            startFunc = f
         }
 
         /**
@@ -58,27 +81,27 @@ class XMLParser private constructor(path: String) {
          * @param f code to execute
          */
         fun end(f: () -> Unit) {
-            if (event.isEndElement && event.asEndElement().name.localPart.toString() == name)
-                f()
+            endFunc = f
         }
 
-        @DSL
-        inner class StartElement(private val reader: XMLEventReader, private val event: javax.xml.stream.events.StartElement) {
-            /**
-             * Get the content of the current element
-             */
-            fun content(): String? {
-                return try {
-                    reader.peek().asCharacters().data
-                } catch (e: ClassCastException) {
-                    null
-                }
-            }
+        /**
+         * Get the content of the current element
+         * @return content of current tag or null
+         */
 
-            /**
-             *
-             */
-            fun attribute(attr: String): String? = event.getAttributeByName(QName(attr))?.value
+        fun content(): String? {
+            return try {
+                reader.peek().asCharacters().data
+            } catch (e: ClassCastException) {
+                null
+            }
         }
+
+        /**
+         * Get attribute of current element if it exists or null. Only works within a start element.
+         * @param attribute attribute name
+         * @return value of attribute or null
+         */
+        fun attribute(attribute: String): String? = event!!.asStartElement().getAttributeByName(QName(attribute))?.value
     }
 }
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