Count table rows UI5 , XML view

Question

Hello,
I want to count ( find the number of rows in a table , or in my model ) .
I have a model ( json ) and i apply this model to a table. I tried to find how many rows I have in my table but i couldn't.
Can you help me ? 
The view ( xml ) looks like this :
<Table id="doc_table"
    inset="false"
    items="{
      path: '/Documents',
      sorter: {
        path: 'Document_Id'
    >
    <headerToolbar>
      <Toolbar>
        <Label text="Products"></Label>
      </Toolbar>
    </headerToolbar>
    <columns>
      <Column
        width="12em">
        <Label text="Document_id" />
      </Column>
      <Column
        minScreenWidth="Tablet"
        demandPopin="true">
        <Label text="Partner_id" />
      </Column>
      <Column
        minScreenWidth="Tablet"
        demandPopin="true"
        hAlign="Right">
        <Label text="PolicyNr" />
      </Column>
      <Column
        minScreenWidth="Tablet"
        demandPopin="true"
        hAlign="Center">
        <Label text="RepvalDescr" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="RepvalType" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="Reportbeg" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="Reportend" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="Repval" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="Repdate" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="DueDate" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="Currency" />
      </Column>
      <Column
        hAlign="Right">
        <Label text="Submit" />
      </Column>
    </columns>
    <items>
      <ColumnListItem>
        <cells>
          <Text
            text="{Document_Id}" />
          <Text
            text="{Partner_Id}" />
          <Text
            text="{PolicyNr}" />
          <Text
            text="{RepvalDescr}"/>
          <Text
          text="{RepvalType}" />
          <Text
            text="{Reportbeg}" />
          <Text
            text="{Reportend}" />
          <Text
            text="{Repval}" />
          <Text
            text="{Repdate}"/>
          <Text
          text="{DueDate}" />
          <Text
            text="{Currency}"/>
          <Text
          text="{Submit}" />
        </cells>
      </ColumnListItem>
    </items>
  </Table>
and in the controller ( .js ) i tried a lot of things , none with good results :
var rowsd = view.getElementById("doc_table").getElementsByTagName("tbody")[0].getElementsByTagName("tr").length;
var rows = this.getView().byId("doc_table").getElementsByTagName("tbody").length;
table.getBinding("items").filter(oFilter).length;
I tried all that i found ,,, but nothing works .
Thank you !

Answer 1

i tried to do this but in browser , in inspect element i get : Cannot read property 'length' of undefined
my code :
var table = new sap.ui.table.Table();
  table = this.getView().byId("doc_table");
  var oModel = new sap.ui.model.json.JSONModel("model/mock.json");
     table.setModel(oModel);
     var count =oModel.getProperty("/Documents").length;