使用 JAXB 将两个同构 XML 模式解析为一个类结构

Question

Consider two isomorphous XML schemas. By isomorphism here I mean that these two schemas have identical structures except attributes and tags names. More specifically I have live example when was schema, say A , and its copy B , where all tags and attribute names were translated from English into national lamguage equivalents.

For example, as input we can have two different variants of one object:

<tag_1_v1>
    <tag_2_v1 id="blabla" name="xxxxx">
        Some value1
    </tag_2_v1>
    <tag_3_v1 id="alalala" name="yyyyy">
        Some value2
    </tag_3_v1>
</tag_1_v1>

and

<tag_1_v2>
    <tag_2_v2 special_id_2="blabla" name="xxxxx">
        Some value1
    </tag_2_v2>
    <tag_3_v2 id="alalala" special_name_2="yyyyy">
        Some value2
    </tag_3_v2>
</tag_1_v2>

The problem is to map these two schemas on single class structure, say

class Tag1 {
    Tag2 tag2;
    Tag3 tag3;
}

class Tag2 {
    String id;
    String name;
    String value;
}  

class Tag3 {
    String id;
    String name;
    String value;
} 

There are various ideas how to workaround this issue, but all of them aren't so convinient, as any possibility to use single JAXB annotation scheme on same class structure. They are:

1. create two different class-sets and then copy values from objects of one schema into another;
2. create own SAX parser implementation and "translate" inside it tag and attribute names into appropriate ones;
3. use own preprocessor of XML and use string replacement (will not work if id and attributes name aren't identical within all schema).

Answer 1

Since each <tag_i> can have different attributes, a clean solution would be to use inheritance:

• Create an abstract class Tag1 that is inherited by Tag1V1 and Tag1V2 . Factor all the common code into Tag1 .
• The same would go Tag2 and Tag3 .

To get you started, here would be an implementation of Tag2 :

@XmlRootElement
@XmlSeeAlso({Tag2V1.class, Tag2V2.class})
abstract class Tag2 {

    private String name;
    private String content;

    @XmlAttribute(name = "name")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @XmlValue
    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

}

@XmlRootElement(name = "tag_2_v1")
class Tag2V1 extends Tag2 {

    private String id;

    @XmlAttribute(name = "id")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

}

@XmlRootElement(name = "tag_2_v2")
class Tag2V2 extends Tag2 {

    private String specialId2;

    @XmlAttribute(name = "special_id_2")
    public String getSpecialId2() {
        return specialId2;
    }

    public void setSpecialId2(String specialId2) {
        this.specialId2 = specialId2;
    }

}