tagBuilder and singleton

students/2816977791/ood/ood-assignment/src/main/java/com/coderings/dp/builder/TagBuilder.java

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+package com.coderings.dp.builder;
+
+public class TagBuilder {
+
+    final TagNode rootNode;
+
+    TagNode iteratorNode;
+
+    TagNode prevIteratorNode;
+
+    public TagBuilder(String rootTagName) {
+        rootNode = new TagNode(rootTagName);
+        iteratorNode = rootNode;
+        prevIteratorNode = rootNode;
+    }
+
+    public TagBuilder addChild(String childTagName) {
+        TagNode tagNode = new TagNode(childTagName);
+        iteratorNode.add(tagNode);
+
+        prevIteratorNode = iteratorNode;
+        iteratorNode = tagNode;
+
+        return this;
+    }
+
+    public TagBuilder addSibling(String siblingTagName) {
+        TagNode tagNode = new TagNode(siblingTagName);
+        prevIteratorNode.add(tagNode);
+
+        iteratorNode = tagNode;
+
+        return this;
+    }
+
+    public TagBuilder setAttribute(String name, String value) {
+        iteratorNode.setAttribute(name, value);
+        return this;
+    }
+
+    public TagBuilder setText(String value) {
+        iteratorNode.setValue(value);
+        return this;
+    }
+
+    public String toXML() {
+        return rootNode.toXML();
+    }
+}

students/2816977791/ood/ood-assignment/src/main/java/com/coderings/dp/builder/TagBuilderTest.java

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+package com.coderings.dp.builder;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class TagBuilderTest {
+
+	@Before
+	public void setUp() throws Exception {
+	}
+
+	@After
+	public void tearDown() throws Exception {
+	}
+
+	@Test
+	public void testToXML() {
+
+		TagBuilder builder = new TagBuilder("order");
+
+		String xml = builder.addChild("line-items")
+			.addChild("line-item").setAttribute("pid", "P3677").setAttribute("qty", "3")
+			.addSibling("line-item").setAttribute("pid", "P9877").setAttribute("qty", "10")
+			.toXML();
+
+		String expected = "<order>"
+				+ "<line-items>"
+				+ "<line-item pid=\"P3677\" qty=\"3\"/>"
+				+ "<line-item pid=\"P9877\" qty=\"10\"/>"
+				+ "</line-items>"
+				+ "</order>";
+
+		System.out.println(xml);
+		assertEquals(expected, xml);
+	}
+
+}

students/2816977791/ood/ood-assignment/src/main/java/com/coderings/dp/builder/TagNode.java

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+package com.coderings.dp.builder;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TagNode {
+	private String tagName;	
+	private String tagValue;
+	private List<TagNode> children = new ArrayList<>();	
+	private List<Attribute> attributes = new ArrayList<>();
+
+	public TagNode(String name){
+		this.tagName = name;
+	}
+	public void add(TagNode child){
+		this.children.add(child);
+	}
+	public void setAttribute(String name, String value) {
+		Attribute attr = findAttribute(name);
+		if(attr != null){
+			attr.value = value;
+			return;
+		}
+
+		attributes.add(new Attribute(name,value));
+	}
+	private Attribute findAttribute(String name){
+		for(Attribute attr : attributes){
+			if(attr.name.equals(name)){
+				return attr;
+			}
+		}
+		return null;
+	}
+	public void setValue(String value) {
+		this.tagValue = value;
+
+	}
+	public String getTagName() {
+		return tagName;
+	}
+	public List<TagNode> getChildren() {
+		return children;
+	}
+
+	private static class Attribute{
+		public Attribute(String name, String value) {
+			this.name = name;
+			this.value = value;
+		}
+		String name;
+		String value;
+
+	}
+	public String toXML(){
+		return toXML(this);
+	}
+	private String toXML(TagNode node){
+		StringBuilder buffer = new StringBuilder();
+		buffer.append("<").append(node.tagName);
+		if(node.attributes.size()> 0){
+			for(int i=0;i<node.attributes.size();i++){
+				Attribute attr = node.attributes.get(i);
+				buffer.append(" ").append(toXML(attr));				
+			}
+		}
+		if(node.children.size()== 0){
+			buffer.append("/>");
+			return buffer.toString();
+		}
+		buffer.append(">");		
+		for(TagNode childNode : node.children){
+			buffer.append(toXML(childNode));
+		}
+		buffer.append("</").append(node.tagName).append(">");
+
+
+		return buffer.toString();
+	}
+	private String toXML(Attribute attr){
+		return attr.name+"=\""+attr.value + "\"";
+	}
+}

students/2816977791/ood/ood-assignment/src/main/java/com/coderings/dp/singleton/jdk_singleton.md

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+#Singleton in JDK
+
+## java.lang.Runtime
+
+    private static Runtime currentRuntime = new Runtime();
+
+    public static Runtime getRuntime() {
+        return currentRuntime;
+    }
+
+## java.awt.Desktop
+
+    private DesktopPeer peer;
+
+    private Desktop() {
+        peer = Toolkit.getDefaultToolkit().createDesktopPeer(this);
+    }
+
+
+    public static synchronized Desktop getDesktop(){
+        Desktop desktop = (Desktop)context.get(Desktop.class);
+        
+        if (desktop == null) {
+            desktop = new Desktop();
+            context.put(Desktop.class, desktop);
+        }
+        
+        return desktop;
+    }
+
+## java.lang.System
+
+    private static volatile SecurityManager security = null;
+
+    public static SecurityManager getSecurityManager() {
+        return security;
+    }
+