initial version of the query autocompletion

Missing features at this point:
1. No suggestions when the input gets the focus.
2. Suggestions are not shown after selecting a suggestion.

pdb-js/src/app/plot.service.ts

@@ -1,5 +1,5 @@
 import { Injectable, OnInit } from '@angular/core';
-import { HttpClient } from '@angular/common/http';
+import { HttpClient, HttpParams } from '@angular/common/http';
 import { Observable } from 'rxjs/Observable';
 
 
@@ -11,7 +11,7 @@ export class PlotService {
   plotTypes: Array<PlotType>;
   
   tagFields: Array<TagField>;
-
+  
   constructor(private http: HttpClient) {
     this.plotTypes = new Array<PlotType>();
     this.plotTypes.push(new PlotType(
@@ -55,6 +55,16 @@ export class PlotService {
     });
     return this.tagFields;
   }
+  
+  autocomplete(query: string, caretIndex: number): Observable<AutocompleteResult>
+  {
+    const options = { 
+      params: new HttpParams()
+        .set('caretIndex', ""+caretIndex)
+        .set('query', query) 
+    };
+    return this.http.get<AutocompleteResult>('//'+window.location.hostname+':8080/autocomplete', options);
+  }
 }
 
 
@@ -111,3 +121,17 @@ export enum DataType {
     Other
 }
 
+export class Suggestion {
+  value: string;
+  newQuery: string;
+  newCaretPosition: number;
+}
+
+
+export class AutocompleteResult{
+  proposals: Array<Suggestion>;
+}
+
+
+
+