Convert JSON zu einem Vaadin Charts Theme mit Gson

Question

Ich habe folgende JSON aus der einem Chart Standard-Theme Vaadin serialisiert:

{ 
    "colors":[ 
    { 
    "color":"#2f7ed8" 
    }, 
    { 
    "color":"#0d233a" 
    }, 
    { 
    "color":"#8bbc21" 
    }, 
    { 
    "color":"#910000" 
    }, 
    { 
    "color":"#1aadce" 
    }, 
    { 
    "color":"#492970" 
    }, 
    { 
    "color":"#f28f43" 
    }, 
    { 
    "color":"#77a1e5" 
    }, 
    { 
    "color":"#c42525" 
    }, 
    { 
    "color":"#a6c96a" 
    } 
], 
"chart":{ 
    "backgroundcolor":{ 
    "color":"#FFFFFF" 
    }, 
    "plotBackgroundcolor":{ 
    "color":"rgba(255,255,255,0.00)" 
    }, 
    "plotBackgroundImage":"", 
    "plotShadow":false, 
    "plotBorderWidth":0, 
    "plotBordercolor":{ 
    "color":"#C0C0C0" 
    }, 
    "className":"", 
    "style":{ 
    "fontFamily":"\"Lucida Grande\", \"Lucida Sans Unicode\", Verdana, Arial, Helvetica, sans-serif", 
    "fontSize":"12px" 
    } 
}, 
"title":{ 
    "style":{ 
    "color":{ 
     "color":"#3E576F" 
    }, 
    "fontWeight":"NORMAL", 
    "fontSize":"16px" 
    } 
}, 
"subtitle":{ 
    "style":{ 
    "color":{ 
     "color":"#6D869F" 
    }, 
    "fontWeight":"NORMAL", 
    "fontSize":"12px" 
    } 
}, 
"xAxis":{ 
    "linecolor":{ 
    "color":"#C0D0E0" 
    }, 
    "lineWidth":1, 
    "tickcolor":{ 
    "color":"#C0D0E0" 
    }, 
    "gridLinecolor":{ 
    "color":"#C0C0C0" 
    }, 
    "gridLineWidth":0, 
    "alternateGridcolor":{ 
    "color":"rgba(255,255,255,0.00)" 
    }, 
    "title":{ 
    "style":{ 
     "color":{ 
      "color":"#3E576F" 
     }, 
     "fontWeight":"NORMAL" 
    } 
    }, 
    "subtitle":{ 
    "style":{ 
     "color":{ 
      "color":"#666666" 
     }, 
     "fontWeight":"NORMAL", 
     "fontSize":"10px" 
    } 
    }, 
    "labels":{ 
    "style":{ 
     "color":{ 
      "color":"#666666" 
     }, 
     "fontWeight":"NORMAL", 
     "fontSize":"11px" 
    } 
    } 
}, 
"yAxis":{ 
    "minorTickInterval":"NONE", 
    "linecolor":{ 
    "color":"#C0D0E0" 
    }, 
    "lineWidth":0, 
    "tickWidth":0, 
    "tickcolor":{ 
    "color":"#C0D0E0" 
    }, 
    "gridLinecolor":{ 
    "color":"#C0C0C0" 
    }, 
    "gridLineWidth":1, 
    "alternateGridcolor":{ 
    "color":"rgba(255,255,255,0.00)" 
    }, 
    "title":{ 
    "style":{ 
     "color":{ 
      "color":"#3E576F" 
     }, 
     "fontWeight":"NORMAL" 
    } 
    }, 
    "subtitle":{ 
    "style":{ 
     "color":{ 
      "color":"#666666" 
     }, 
     "fontWeight":"NORMAL", 
     "fontSize":"10px" 
    } 
    }, 
    "labels":{ 
    "style":{ 
     "color":{ 
      "color":"#666666" 
     }, 
     "fontWeight":"NORMAL", 
     "fontSize":"11px" 
    } 
    } 
}, 
"labels":{ 
    "style":{ 

    } 
}, 
"legend":{ 
    "backgroundcolor":{ 
    "color":"rgba(255,255,255,0.00)" 
    }, 
    "bordercolor":{ 
    "color":"#646464" 
    }, 
    "borderRadius":5, 
    "itemHiddenStyle":{ 
    "color":{ 
     "color":"#CCC" 
    } 
    }, 
    "itemHoverStyle":{ 
    "color":{ 
     "color":"#000" 
    } 
    }, 
    "itemStyle":{ 
    "color":{ 
     "color":"#3E576F" 
    }, 
    "position":"RELATIVE" 
    } 
}, 
"tooltip":{ 
    "backgroundcolor":{ 
    "color":"rgba(255,255,255,0.85)" 
    }, 
    "borderWidth":2, 
    "followPointer":false, 
    "style":{ 
    "color":{ 
     "color":"#333333" 
    } 
    } 
}, 
"plotOptions":{ 
    "area":{ 
    "shadow":false 
    }, 
    "arearange":{ 
    "shadow":false 
    }, 
    "areaspline":{ 

    }, 
    "areasplinerange":{ 
    "shadow":false 
    }, 
    "bar":{ 
    "shadow":false 
    }, 
    "boxplot":{ 

    }, 
    "bubble":{ 

    }, 
    "column":{ 
    "shadow":false 
    }, 
    "columnrange":{ 

    }, 
    "errorbar":{ 

    }, 
    "funnel":{ 

    }, 
    "gauge":{ 

    }, 
    "heatmap":{ 

    }, 
    "line":{ 
    "shadow":false 
    }, 
    "pie":{ 
    "shadow":false 
    }, 
    "polygon":{ 

    }, 
    "pyramid":{ 

    }, 
    "scatter":{ 

    }, 
    "series":{ 

    }, 
    "solidgauge":{ 

    }, 
    "spline":{ 
    "shadow":false 
    }, 
    "treemap":{ 

    }, 
    "waterfall":{ 

    }, 
    "candlestick":{ 

    }, 
    "flags":{ 

    }, 
    "ohlc":{ 

    } 
}, 
"credits":{ 

} 
} 

und das ist das Thema Klasse:

/** 
* Theme class for Chart. This is empty theme, and only defines the structure of 
* Theme. Inherit own Theme class, or use Themes inherited from this class to 
* theme your Charts. 
* 
* @see VaadinTheme 
*/ 
public class Theme extends AbstractConfigurationObject { 
    private Color[] colors; //This is an interface and is what is causing problems 
    private ChartStyle chart = new ChartStyle(); 
    private StyleWrapper title = new StyleWrapper(); 
    private StyleWrapper subtitle = new StyleWrapper(); 
    private AxisStyle xAxis = new AxisStyle(); 
    private AxisStyle yAxis = new AxisStyle(); 
    private StyleWrapper labels = new StyleWrapper(); 
    private LegendStyle legend = new LegendStyle(); 
    private TooltipStyle tooltip = new TooltipStyle(); 
    private PlotOptionsStyle plotOptions = new PlotOptionsStyle(); 
    private Credits credits = new Credits(); 

    //Getters and setters 
} 

Die Idee ist, um ein JSON wie dieses in ein Vaadin Charts Theme zu konvertieren, damit der Administrator meiner Anwendung die Charts thematisieren kann. Jedoch Gson wirft die folgende Ausnahme:

Caused by: java.lang.RuntimeException: Unable to invoke no-args constructor for interface com.vaadin.addon.charts.model.style.Color. Register an InstanceCreator with Gson for this type may fix this problem. 
at com.google.gson.internal.ConstructorConstructor$14.construct(ConstructorConstructor.java:226) 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:207) 
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:40) 
at com.google.gson.internal.bind.ArrayTypeAdapter.read(ArrayTypeAdapter.java:72) 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:117) 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:217) 
at com.google.gson.Gson.fromJson(Gson.java:861) 
at com.google.gson.Gson.fromJson(Gson.java:799) 
at es.cic.luca.web.vaadin.elementos.GeneradorGrafica.crearThemeFromJson(GeneradorGrafica.java:1214) 
at es.cic.luca.web.vaadin.elementos.GeneradorGrafica.generar(GeneradorGrafica.java:93) 
at es.cic.luca.web.vaadin.vista.CreacionGraficasVista.lambda$1(CreacionGraficasVista.java:426) 
at es.cic.luca.web.vaadin.vista.CreacionGraficasVista$$Lambda$82/1320668893.buttonClick(Unknown Source) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
at java.lang.reflect.Method.invoke(Unknown Source) 
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:508) 
... 83 more 

Caused by: java.lang.reflect.InvocationTargetException 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
at java.lang.reflect.Method.invoke(Unknown Source) 
at com.google.gson.internal.UnsafeAllocator$1.newInstance(UnsafeAllocator.java:48) 
at com.google.gson.internal.ConstructorConstructor$14.construct(ConstructorConstructor.java:223) 
... 99 more 

Caused by: java.lang.InstantiationException: com.vaadin.addon.charts.model.style.Color 
at sun.misc.Unsafe.allocateInstance(Native Method) 
... 105 more 

ich die Klasse erstellt ColorInstanceCreator das Problem zu lösen:

public class ColorInstanceCreator implements InstanceCreator<Color> { 

    @Override 
    public Color createInstance(Type type) { 
     return new SolidColor(""); 
    } 
} 

Und machen Gson es zu benutzen:

Gson gson = new GsonBuilder().registerTypeAdapter(Color.class,new ColorInstanceCreator()).create(); 

Dieses löst das Problem aber Alle Farben in der konvertierten Klasse sind schwarz (#000000).

Ich habe auch versucht, einen benutzerdefinierten Serializer/Deserializer die ich here gefunden zu schaffen, aber es funktioniert nicht:

Caused by: com.google.gson.JsonParseException: no 'type' member found in what was expected to be an interface wrapper 
at es.cic.luca.web.vaadin.elementos.GeneradorGrafica$InterfaceAdapter.get(GeneradorGrafica.java:1248) 
at es.cic.luca.web.vaadin.elementos.GeneradorGrafica$InterfaceAdapter.deserialize(GeneradorGrafica.java:1231) 
at com.google.gson.TreeTypeAdapter.read(TreeTypeAdapter.java:58) 
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:40) 
at com.google.gson.internal.bind.ArrayTypeAdapter.read(ArrayTypeAdapter.java:72) 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:117) 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:217) 
at com.google.gson.Gson.fromJson(Gson.java:861) 
at com.google.gson.Gson.fromJson(Gson.java:799) 
at es.cic.luca.web.vaadin.elementos.GeneradorGrafica.crearThemeFromJson(GeneradorGrafica.java:1213) 
at es.cic.luca.web.vaadin.elementos.GeneradorGrafica.generar(GeneradorGrafica.java:93) 
at es.cic.luca.web.vaadin.vista.CreacionGraficasVista.lambda$1(CreacionGraficasVista.java:426) 
at es.cic.luca.web.vaadin.vista.CreacionGraficasVista$$Lambda$124/1623517905.buttonClick(Unknown Source) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
at java.lang.reflect.Method.invoke(Unknown Source) 
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:508) 
... 83 more 

Was kann ich tun, um mein Problem zu lösen?

Answer 1

I angepasst this Code mein Problem zu lösen, und hier ist die Lösung:

final class ColorAdapter implements JsonDeserializer<Color> { 

    public Color deserialize(JsonElement elem, Type interfaceType, 
      JsonDeserializationContext context) throws JsonParseException { 
     Color toReturn = null; 
     if(elem instanceof JsonPrimitive) { 
      final JsonPrimitive color = elem.getAsJsonPrimitive(); 
      toReturn = new SolidColor(color.getAsString()); 
     } else { 
      final JsonObject wrapper = (JsonObject) elem; 
      final JsonElement data = get(wrapper, "color"); 
      toReturn = context.deserialize(data, Color.class); 
     } 
     return toReturn; 
    } 

    private JsonElement get(final JsonObject wrapper, String memberName) { 
     final JsonElement elem = wrapper.get(memberName); 
     if (elem == null) 
      throw new JsonParseException(
        "no '" 
          + memberName 
          + "' member found in what was expected to be an interface wrapper"); 
     return elem; 
    } 
}