Package com.onwbp.adaptation

Class PrimaryKey

java.lang.Object
com.onwbp.adaptation.PrimaryKey
public abstract class PrimaryKey extends Object
An instance of a PrimaryKey uniquely identifies a record in a table. The composition of a primary key is defined in the data model using the element osd:table/primaryKeys.

A PrimaryKey is used to perform direct lookups in a table. The string that represents it internally is also used as the value of foreign keys, namely fields declared as osd:tableRef. However, the shortest way to look up a record from an osd:tableRef field is to directly invoke the method SchemaFacetTableRef.getLinkedRecord(ValueContext).

External applications which access and input data containing osd:tableRef fields must conform to the internal syntax described below in Syntax of the internal String representation of primary keys.

Factory and conversion

Factory and conversion methods are as follows:

Syntax of the internal String representation of primary keys

To simplify declaration, representation, and persistence, a primary key is handled as a String, even when it is composed of several fields. Note that the fields composing a primary key are returned by the method SchemaNode.getTablePrimaryKeyNodes(). Specifically, the string is built as follows:

  1. The value of the primary key field is formatted according to the XML Schema standard, as implemented by the method SchemaNode.formatToXsString(Object).
  2. If the primary key is composed of several fields, field values are separated by a "|" pipe, represented by the constant SEPARATOR_CHAR. This may require the following "\" escapes (represented by the constant ESCAPE_CHAR) in a component field, in the case where its own value is not a foreign key:
    • each "|" character in the field value is escaped by a "\";
    • each "\" character in the field value is escaped by "\";

In the following examples, the first column shows a primary key value that is composed of two fields, and the second column gives its corresponding tableRef or PrimaryKey value:

Primary key field values String representation
"1", "2" "1|2"
"1", "2|3" "1|2\|3" if the second field is not a foreign key
"1|2|3" if the second field is a foreign key
"1|2", "3" "1\|2|3" if the first field is not a foreign key
"1|2|3" if the first field is a foreign key
"1\", "2" "1\\|2"

Validity of the String representation of primary keys

If the String representation of a primary key is not structurally valid, an InvalidPrimaryKeyException is thrown. The following table gives some examples:

Key structure String representation Structural validity
(xs:string) "" (empty string) Valid. Will look up a record with a single primary key field set to an empty string.
(xs:int) "" (empty string) Invalid, throws an InvalidPrimaryKeyException.
(xs:int) "aa" (invalid integer) Invalid, throws an InvalidPrimaryKeyException.
(xs:int | xs:string) "aa|aaa" (invalid integer field) Invalid, throws an InvalidPrimaryKeyException.
(xs:int | xs:string) "|aaa" Invalid, throws an InvalidPrimaryKeyException.
(xs:int | xs:string) "" (empty string) Invalid, throws an InvalidPrimaryKeyException.
(xs:int | xs:string) "aaa" Invalid, throws an InvalidPrimaryKeyException.
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final char
    ESCAPE_CHAR
    Character ("\") used for escaping a pipe ("|") or backslash ("\") character if it occurs in the value of a non-foreign-key field.
    static final String
    SEPARATOR
    Single pipe character ("|") separator between two fields, when primary key is a composite of multiple fields.
    static final char
    SEPARATOR_CHAR
    Single pipe character ("|") separator between two fields, when primary key is a composite of multiple fields.
    static final PrimaryKey
    VOID_KEY
    PrimaryKey with an empty string as its internal representation.

  • Method Summary

    Modifier and Type
    Method
    Description
    final boolean
    equals(Object anObject)
    Returns true if the specified object has the same logical content of this instance.
    final boolean
    equalsToPrimaryKey(PrimaryKey aPrimaryKey)
    Returns true if the specified object has the same logical content of this instance.
    abstract String
    format()
    Returns the internal String representation of this PrimaryKey instance.
    abstract int
    hashCode()
     
    static PrimaryKey
    parseList(List aList)
    Deprecated.
    This method does not support the use of certain characters in the elements of the specified List.
    static String
    parseObjects(Object[] fieldsValues, SchemaNode[] fieldsNodes)
    Returns the internal representation string that corresponds to the concrete values of a PrimaryKey.
    static PrimaryKey
    parseString(String aTableRefValue)
    Returns the PrimaryKey that corresponds to the specified internal representation String.
    final String
    toString()
     

    Methods inherited from class java.lang.Object

    getClass, notify, notifyAll, wait, wait, wait