I am using a D3 api in which i am representing some hierarchy between the nodes through links between them.all the data comes from database when i load the page.But here i have a criteria where i have to filter top 3 or 5 nodes i.e i have a select box here where i have values from 1 to 5.Now if i go for 2 the database will return the hierarchy for 2nd level.But i have a problem here when i load the page ,onload it will return a default level from the database,but when i go for 2nd or 3 rd level the database will generate the required json but this time the api is not populating along with the values,instead it is returning/printing the calculated json in the html page. Here is my code ...
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.node circle {
cursor: pointer;
stroke: #3182bd;
stroke-width: 1.5px;
}
.node text {
font: 10px sans-serif;
pointer-events: none;
text-anchor: middle;
}
line.link {
fill: none;
stroke: #9ecae1;
stroke-width: 1.5px;
}
</style>
<body>
<script type="text/javascript" src="d3/d3.v3.min.js"></script>
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script>
var width = 1200,
height = 700,
root;
var force = d3.layout.force()
.linkDistance(80)
.charge(-120)
.gravity(.04)
.size([width, height])
.on("tick", tick);
//adding as svg element
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var link = svg.selectAll(".link"),
node = svg.selectAll(".node");
d3.json("JsonServlet", function(error, json) {
root = json;
update(); //responsible for creating the layout
});
function update() {
var nodes = flatten(root),
/*
*d3.layout.tree() is the starting point
*for tree layouts in D3.
*The call to this function returns an object
* that contains a bunch of methods to configure
* the layout and also provides methods to
* compute the layout
**/
links = d3.layout.tree().links(nodes);//attach the nodes
// Restart the force layout.
force
.nodes(nodes)
.links(links)
.start();
// Update links.
link = link.data(links, function(d) { return d.target.id; });
link.exit().remove();
link.enter().insert("line", ".node")
.attr("class", "link");
// Update nodes.
node = node.data(nodes, function(d) { return d.id; });
node.exit().remove();
var nodeEnter = node.enter().append("g")
.attr("class", "node")
.on("click", click)
.call(force.drag);
nodeEnter.append("circle")
.attr("r", function(d) { return Math.sqrt(d.size) / 10 || 4.5; });
nodeEnter.append("text")
.attr("dy", ".35em")
.text(function(d) { return d.name; });
node.select("circle")
.style("fill", color);
}
/*Giving elements on click*/
function tick() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
}
/*Adjusting the color of each node*/
function color(d) {
return d._children ? "#3182bd" // collapsed package
: d.children ? "#c6dbef" // expanded package
: "#fd8d3c"; // leaf node
}
var checkNodes = [];
// Toggle children on click.
function click(d) {
checkNodes.push(d);
update();
}
function collectNames(){
var res = []
checkNodes.forEach(function(v){
res.push(v.name);
})
return res;
}
function send(){
var name=d.name;
$.ajax({
url: "ActionServlet",
type: "post",
//data: [extract each node names from "checkNodes"],
data:collectNames(),//send name array to server
error:function(){
//alert("error occured!!!");
},
success:function(d){
//alert(d.name);
}
});
checkNodes = [];//clear
};
// Returns a list of all nodes under the root.
function flatten(root) {
var nodes = [], i = 0;
function recurse(node) {
if (node.children) node.children.forEach(recurse);
if (!node.id) node.id = ++i;
nodes.push(node);
}
recurse(root);
return nodes;
}
</script>
<form method="post" action="JsonServlet">
<select name="options">
<option>Choose Your Option</option>
<option value="1"> 1</option>
<option value="2"> 2</option>
<option value="3"> 3</option>
<option value="4"> 4</option>
</select>
<input type="submit" value="submit"/>
</form>
This is my servlet
public class JsonServlet extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
int option =Integer.parseInt(request.getParameter("options"));
System.out.println(option);
List<String> listofParent = new ArrayList<String>();
List<String> listofChild = new ArrayList<String>();
DBConn con = new DBConn();
Connection conn = con.getConnection();
Statement st = conn.createStatement();
String sqlQuery = "select * from link_table";
ResultSet rs = st.executeQuery(sqlQuery);
while (rs.next()) {
listofParent.add(rs.getString(1));
listofChild.add(rs.getString(2));
}
Entry mainRoot = null;
Entry e = new Entry("1008574975");
Entry e1 = new Entry("987456215");
for (int i = 0; i < listofParent.size(); i++) {
Entry root = new Entry(listofParent.get(i));
mainRoot = aMethod2form(root, listofChild);
e.add(mainRoot);
}
e1.add(e);
Gson g = new Gson();
System.out.println(g.toJson(e1));
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(g.toJson(e1));
} catch (Exception e) {
e.printStackTrace();
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP
* <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP
* <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
private Entry aMethod2form(Entry root, List<String> listofChild) {
for (int i = 0; i < listofChild.size(); i++) {
root.add(new Entry(listofChild.get(i)));
}
return root;
}
}
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