通过包装NullalbleListEditor实现NullableSetEditor [英] Implement NullableSetEditor by wrapping a NullalbleListEditor

问题描述

  public class NullableStringListEditor扩展Composite implements IsEditor< OptionalFieldEditor< List< String>，ListEditor< String，StringEditor> >> {...} 
  

现在，我通过包装构建一个NullableStringSetEditor：

  public class NullableStringSetEditor extends Composite implements ValueAwareEditor< Set< String>>，LeafValueEditor< Set< String>> {
 private NullableStringListEditor wrappedEditor = new NullableStringListEditor（）; 
 
 @Override 
 public void setValue（Set< String> values）{
 List< String> list = wrappedEditor.asEditor（）。getValue（）; 
一些空的检查... 
 list.clear（）; 
 list.addAll（values）; 
 wrappedEditor.asEditor（）。setValue（list）; //会从这里调用OptionalFieldEditor的setValue 
 
 
 code $ 
 
 
 
错误： 
  java.lang.NullPointerException：com.google.gwt.editor.client.adapters.OptionalFieldEditor.setValue（可选字段编辑器。 java：113）
  
第113行：chain.attach（value，subEditor）; 
它似乎像链始终是空的。
 
 
 
我做错了什么？如果 NullableStringSetEditor 是一个  LeafvalueEditor ，然后 wrappedEditor 将被编辑器框架生成器忽略，因此不会被初始化和填充。
 
 
 
您可能希望通过使您的编辑器成为 CompositeEditor 来遵循 OptionaEditor 模式除了是 LeafValueEditor ）
 
I have a working NullableStringListEditor implementation:
public class NullableStringListEditor extends Composite implements IsEditor<OptionalFieldEditor< List<String>, ListEditor<String, StringEditor> >> {...}
Now, I am building a NullableStringSetEditor by wrapping it:
public class NullableStringSetEditor extends Composite implements ValueAwareEditor<Set<String>>, LeafValueEditor<Set<String>> {
private NullableStringListEditor wrappedEditor = new NullableStringListEditor();

    @Override
    public void setValue(Set<String> values) {
        List<String> list = wrappedEditor.asEditor().getValue();
        some null checking... 
        list.clear();
        list.addAll(values);
        wrappedEditor.asEditor().setValue(list); // will call setValue of OptionalFieldEditor from here
    }
}
Error: 
java.lang.NullPointerException: null at com.google.gwt.editor.client.adapters.OptionalFieldEditor.setValue(OptionalFieldEditor.java:113)
line 113: chain.attach(value, subEditor);
it seems like chain is always null.

Am I doing something wrong? Thanks!
解决方案
If NullableStringSetEditor is a LeafvalueEditor, then wrappedEditor will be ignored by the Editor framework generator, and thus won't be initialized and populated.

You might want to follow the OptionaEditor pattern by having your editor be a CompositeEditor (in addition to being a LeafValueEditor)

                        
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