String type in Java

Create Code 128 Code Set C in Java String type

A string type accepts any literal string of text, or character data (CDATA), as its value You declare string types with the literal CDATA CDATA values are case sensitive, so they must match the declared values exactly You may find that you use string type attributes more than any other attribute type

In the XML Specification, this is the rule for a string type:

If this is your attribute-list declaration:

both the TITLE and the AUTHOR attributes are string types You may use any literal string as the value of these attributes, such as in this start tag for a BOOK element:

Be sure not to confuse CDATA attributes with CDATA sections In CDATA attributes, the XML processor recognizes markup and expands entity references; CDATA sections, on the other hand, are sections of special-character-peppered text you can hide from XML parsers

A tokenized type is a type of data that can contain no white space (and so can be used for identifying purposes, much like a Social Security number or driver s license number) A tokenized type can be any of four specific types (with a total of seven type attributes): IDentifier, or ID, which uniquely identifies an individual element in a document, so each element can have only a single ID attribute Because each ID is unique, all the ID values in a document must differ The value of an ID attribute must be a name Also, you must declare an ID attribute with a default of #IMPLIED or #REQUIRED You may find that the name of an ID attribute is usually ID ID reference, or IDREF or IDREFS, which is a pointer or a set of pointers to an ID attribute value An IDREF attribute s value is the value of a single ID attribute of an element in the document If you need to include more than one ID reference, use IDREFS with multiple values separated by white spaces Entity name, or ENTITY or ENTITIES, which is a pointer or set of pointers to an external entity The value of an ENTITY attribute is the name of an entity, which is case-sensitive to match the name of an external binary general entity declared in the DTD If you need to include more than one entity reference, use ENTITIES with multiple values separated by white spaces

Name token, or NMTOKEN or NMTOKENS, whose value is a mixture of name characters Name token attributes are similar to string type attributes, but they re more restricted In general, a NMTOKEN attribute consists of a single name, as opposed to the literal string of a CDATA attribute, which may contain white spaces and other characters Other than this restriction, you may select any name you want for an NMTOKEN attribute, as long as it matches the NMTOKEN although it doesn t have to match another attribute or declaration If you need to include more than one name token, use NMTOKENS with multiple values separated by white spaces In the XML Specification, the set of rules for tokenized types looks like this:

TokenizedType ::= ID [vc: ID] [vc: One ID per Element Type] [vc: ID Attribute Default] | IDREF [vc: IDREF] | IDREFS [vc: IDREF] | ENTITY [vc: Entity Name] | ENTITIES [vc: Entity Name ] | NMTOKEN [vc: Name Token ] | NMTOKENS [vc: Name Token]

I explain more about the associated validity constraints (vc:) in the Declaring elements section, earlier in this chapter As an example, here are attribute-list declarations for two of the preceding tokenized attribute types along with their corresponding start tags:

ID attribute type: <!ATTLIST DATA ID ID #REQUIRED> <DATA ID= 123 > ENTITY attribute type: <!ATTLIST IMG SRC ENTITY #REQUIRED> <IMG SRC= imagegif />