Flesh out XML read and write utility methods

forge-gui/pom.xml

@@ -51,5 +51,11 @@
             <artifactId>freemarker</artifactId>
             <version>2.3.20</version>
         </dependency>
+        <dependency>
+            <groupId>xmlpull</groupId>
+            <artifactId>xmlpull</artifactId>
+            <version>1.1.3.1</version>
+            <scope>provided</scope>
+        </dependency>
     </dependencies>
 </project>

forge-gui/src/main/java/forge/util/XmlUtil.java

@@ -18,6 +18,9 @@
 package forge.util;
 
 import org.w3c.dom.Node;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserFactory;
+import org.xmlpull.v1.XmlSerializer;
 
 import javax.xml.transform.OutputKeys;
 import javax.xml.transform.Transformer;
@@ -25,12 +28,18 @@ import javax.xml.transform.TransformerException;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
-import java.io.StringWriter;
 
-/**
- * TODO: Write javadoc for this type.
- * 
- */
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.InputStreamReader;
+import java.io.StringWriter;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Stack;
+
+
 public class XmlUtil {
 
     /**
@@ -51,4 +60,136 @@ public class XmlUtil {
         }
         return sw.toString();
     }
+
+    public static void read(String filename, XmlTagReader reader) {
+        try {
+            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
+            factory.setNamespaceAware(true);
+            XmlPullParser xml = factory.newPullParser();
+            xml.setInput(new InputStreamReader(new FileInputStream(filename)));
+
+            int eventType = xml.getEventType();
+            while (eventType != XmlPullParser.END_DOCUMENT) {
+                switch (eventType) {
+                case XmlPullParser.START_TAG:
+                    reader.tagStart(xml);
+                    break;
+                case XmlPullParser.END_TAG:
+                    reader.tagEnd(xml);
+                    break;
+                }
+                eventType = xml.next();
+            }
+        }
+        catch (final FileNotFoundException e) {
+            /* ignore if file doesn't exist */
+        }
+        catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static abstract class XmlTagReader {
+        public abstract void tagStart(XmlPullParser xml);
+        public void tagEnd(XmlPullParser xml) {
+            //not required to override but can be
+        }
+    }
+
+    public static void write(String filename, XmlTagWriter writer) {
+        FileOutputStream outputStream = null;
+        try {
+            outputStream = new FileOutputStream(filename);
+            XmlPullParserFactory factory = XmlPullParserFactory.newInstance(System.getProperty(XmlPullParserFactory.PROPERTY_NAME), null);
+            XmlSerializer xml = factory.newSerializer();
+            xml.setOutput(outputStream, null);
+            xml.startDocument(null, true);
+            xml.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
+            writer.writeTags(new XmlWriter(xml));
+            xml.endDocument();
+            xml.flush();
+            outputStream.close();
+        }
+        catch (Exception e) {
+            e.printStackTrace();
+            if (outputStream != null) {
+                try {
+                    outputStream.close();
+                }
+                catch (Exception e1) {
+                    e1.printStackTrace();
+                }
+            }
+            try {
+                new File(filename).delete(); //delete file if exception
+            }
+            catch (Exception e1) {
+                e1.printStackTrace();
+            }
+        }
+    }
+
+    public static class XmlWriter {
+        private XmlSerializer xml;
+        private Stack<String> tagnames;
+
+        private XmlWriter(XmlSerializer xml0) {
+            xml = xml0;
+        }
+
+        public void startTag(String tagname) {
+            startTag(tagname, null);
+        }
+        public void startTag(String tagname, Map<String, String> attrs) {
+            try {
+                xml.startTag("", tagname);
+                if (attrs != null) {
+                    for (Entry<String, String> attr : attrs.entrySet()) {
+                        xml.attribute("", attr.getKey(), attr.getValue());
+                    }
+                }
+                tagnames.push(tagname);
+            }
+            catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+
+        public void writeTag(String tagname, Map<String, String> attrs) {
+            writeTag(tagname, attrs, null);
+        }
+        public void writeTag(String tagname, String value) {
+            writeTag(tagname, null, value);
+        }
+        public void writeTag(String tagname, Map<String, String> attrs, String value) {
+            try {
+                xml.startTag("", tagname);
+                if (attrs != null) {
+                    for (Entry<String, String> attr : attrs.entrySet()) {
+                        xml.attribute("", attr.getKey(), attr.getValue());
+                    }
+                }
+                if (value != null) {
+                    xml.text(value);
+                }
+                xml.endTag("", tagname);
+            }
+            catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+
+        public void endTag() {
+            try {
+                xml.endTag("", tagnames.pop());
+            }
+            catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    public static abstract class XmlTagWriter {
+        public abstract void writeTags(XmlWriter xml);
+    }
 }