xjc:两个声明导致 ObjectFactory 类中的冲突 [英] xjc: Two declarations cause a collision in the ObjectFactory class
问题描述
运行以下 xjc 命令会引发错误:
Running the following xjc command raises an error :
$ xjc "ftp://ftp.ncbi.nih.gov/bioproject/Schema/Core.xsd"
parsing a schema...
compiling a schema...
[ERROR] Two declarations cause a collision in the ObjectFactory class.
line 340 of ftp://ftp.ncbi.nih.gov/bioproject/Schema/Core.xsd
[ERROR] (Related to above error) This is the other declaration.
line 475 of ftp://ftp.ncbi.nih.gov/bioproject/Schema/Core.xsd
虽然我了解 JAXB 绑定以及 XJC 中的冲突是什么，但我不明白当前模式中的冲突在哪里.
Although I understand the JAXB bindings and what are is conflict in XJC, I don't understand where is the conflict in the current schema.
我应该如何解决这个问题?
how should I fix this ?
谢谢，
皮埃尔
更新:这里是错误的上下文:
update: here is the context of the errors:
$ curl -s "ftp://ftp.ncbi.nih.gov/bioproject/Schema/Core.xsd" | sed 's/^[ ]*//' | cat -n | egrep -w -A 10 -B 10 '(340|475)'
330 <xs:element maxOccurs="1" name="Description"
331 type="xs:string" minOccurs="0">
332 <xs:annotation>
333 <xs:documentation>
334 Optionally provide description especially when "eOther" is selected
335 </xs:documentation>
336 </xs:annotation>
337 </xs:element>
338 <xs:element name="BioSampleSet" minOccurs="0" maxOccurs="1"><xs:annotation><xs:documentation>Identifier of the BioSample when known</xs:documentation>
339 </xs:annotation>
340 <xs:complexType><xs:sequence><xs:element name="ID" maxOccurs="unbounded" type="xs:token"></xs:element>
341 </xs:sequence>
342 </xs:complexType>
343 </xs:element>
344 </xs:sequence>
345 <xs:attribute name="sample_scope" use="required">
346 <xs:annotation>
347 <xs:documentation>
348 The scope and purity of the biological sample used for the study
349 </xs:documentation>
350 </xs:annotation>
--
465 <xs:documentation>Please, fill Description element when choose "eOther"</xs:documentation>
466 </xs:annotation>
467 </xs:enumeration>
468 </xs:restriction>
469 </xs:simpleType>
470 </xs:attribute>
471 </xs:complexType>
472 </xs:element>
473 <xs:element name="TargetBioSampleSet">
474 <xs:annotation><xs:documentation>Set of Targets references to BioSamples</xs:documentation></xs:annotation>
475 <xs:complexType>
476 <xs:sequence>
477 <xs:element name="ID" type="xs:token" minOccurs="1" maxOccurs="unbounded"></xs:element>
478 </xs:sequence>
479 </xs:complexType>
480 </xs:element>
481 </xs:choice>
482 <xs:element name="Method" minOccurs="1">
483 <xs:annotation>
484 <xs:documentation>
485 The core experimental approach used to obtain the data that is submitted to archival databases
推荐答案
我将引用 最官方的非官方网络上的 JAXB 指南.
当模式包含相似的元素/类型名称时，它们可以导致两个声明导致 ObjectFactory 中的冲突类"错误.更准确地说，对于所有类型和许多元素(确切地说，哪些元素获得了工厂，哪些没有很难解释)，XJC 在 ObjectFactory 类上生成一个方法在同一个包中.ObjectFactory 类是为每个XJC 生成一些文件的包.该方法的名称是派生自 XML 元素/类型名称，如果有两个则报错元素/类型尝试生成相同的方法名称.
When schemas contain similar looking element/type names, they can result in "Two declarations cause a collision in the ObjectFactory class" errors. To be more precise, for each of all types and many elements (exactly what elements get a factory and what doesn't is bit tricky to explain), XJC produces one method on the ObjectFactory class in the same package. The ObjectFactory class is created for each package that XJC generates some files into. The name of the method is derived from XML element/type names, and the error is reported if two elements/types try to generate the same method name.
也就是说，您有两个选择.
That said, you have two options.
首先是定义一个这样的外部绑定XML
The first is to define an external binding XML like this
<jaxb:bindings xmlns:jaxb="http://java.sun.com/xml/ns/jaxb"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
version="1.0">
<jaxb:bindings schemaLocation="Core.xsd">
<jaxb:bindings node="//xs:element[@name='BioSampleSet']/xs:complexType">
<jaxb:factoryMethod name="TypeBioSampleSet"/>
</jaxb:bindings>
<jaxb:bindings node="//xs:element[@name='TargetBioSampleSet']/xs:complexType">
<jaxb:factoryMethod name="TypeTargetBioSampleSet"/>
</jaxb:bindings>
</jaxb:bindings>
</jaxb:bindings>
在生成的 ObjectFactory 类中，这将创建两个名为 createTypeBioSampleSet 和 createTypeTargetBioSampleSet 的方法(JAXB 会将您指定的名称附加到单词 create) 可用于生成 BioSampleSet 和 TargetBioSampleSet 对象.
In the generated ObjectFactory class this will create two methods called createTypeBioSampleSet and createTypeTargetBioSampleSet (JAXB will append the name you specify to the word create) that can be used to produce BioSampleSet and TargetBioSampleSet objects.
(没有必要为两种类型定义绑定.)
(It's not necessary to define a binding for both types.)
我不完全确定为什么 JAXB 拒绝从给定的模式生成类，但是当我只指定一个绑定(例如对于 BioSampleSet)时，另一种类型的工厂方法被命名为 createTypeProjectProjectTypeSubmissionWhateverThisAndThatTargetTargetSampleBioCatDogWoofTypeIDoNotKnowWhatElse 所以我认为 JAXB 被这个长方法标识符阻塞了，因为它以某种方式设法为两种类型创建了相同的标识符.我认为这是 JAXB 中的一些实现细节.
I'm not exactly sure why JAXB refuses to generate classes from the given schema, but when I specified only one binding (for BioSampleSet for example) then the other type's factory method was named like createTypeProjectProjectTypeSubmissionWhateverThisAndThatTargetTargetSampleBioCatDogWoofTypeIDoNotKnowWhatElse so I think JAXB choked on this long method identifier, because it somehow managed to create the same one for both types. I think this is some implementation detail in JAXB.
另一种解决方案是为 BioSampleSet 创建一个基本类型，并像这样在两个位置使用它
The other solution is to create a base type for a BioSampleSet and use that at both locations like this
<xs:element name="ProjectTypeSubmission">
...
<xs:element name="Target">
...
<xs:element name="BioSampleSet" type="typeBioSampleSet" minOccurs="0" maxOccurs="1"/>
...
</xs:element>
...
<xs:element name="TargetBioSampleSet" type="typeBioSampleSet"/>
...
<xs:element/>
...
<xs:complexType name="typeBioSampleSet">
<xs:sequence>
<xs:element name="ID" maxOccurs="unbounded" type="xs:token"></xs:element>
</xs:sequence>
</xs:complexType>
最好的解决方案是从架构中删除每个匿名类型声明.如果你能做到，那就去做吧，因为这个模式看起来一团糟(至少对我来说).
The best solution would be to drop every anonymous type declarations from your schema. If you can do that, do it, because this schema looks like a mess (to me at least).
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