■The Merge operation is commutative, so with API A and B, A + B = B + A.

■It recognizes either binary or source compatibility when merging APIs.

■For any application X that is compatible with either API A or B, when A and B are merged then X must be compatible with the resulting API C.

■The resulting API C cannot contain a class that is not found in either of the A or B input APIs. This means that any class in C has to have corresponding classes in either A or B or both A and B.

■API C must not contain a class member that is not found in its corresponding classes in A and B. This applies only to declared class members and not inherited members.

■If some class in A or B, or both, has a member that overrides a member from a superclass, then the corresponding class in C must also have this overriding member.

■Each API element in C has a set of attributes derived from the attributes of its corresponding elements in A and B, and this is the smallest possible set of attributes that does not break compatibility. So if attr is an attribute of an element from API C, then attr must be defined for the corresponding element from A or B, and attr can not be omitted without breaking compatibility between A and C or between B and C.

■No unnecessary APIs or relationships between classes or interfaces can be introduced.

The basic algorithmic rules for combining two input APIs A and B into a signature file that represents the resulting API C are as follows:

■If one of the input APIs A or B contains an element that the other does not, then this element goes into the resulting signature file of API C without modification except for the following case: If the element in question is the first declared class member in the inheritance chain of input API A or B, and the other input API inherits the same element, then this element represented the resulting API C.

■If both of the input APIs contain two identical elements, only one of them is represented in the resulting API.

■If both of the input APIs contain a corresponding element, but with a different set of attributes, then either of the following occurs:

■A conflict wherein the resulting API can not exist.

■A compromise wherein the new element with a composite set of attributes is created and it is represented in the resulting API-set.

Element Handling by Merge

General rules for handling elements of all kinds during the Merge process are as follows.

12 Signature Test Tool 2.0 User’s Guide • April 2008

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Sun Microsystems 2 manual Element Handling by Merge
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2 specifications

Sun Microsystems, founded in 1982, was a significant player in the computing industry, best known for its innovative technology solutions and workstations, particularly the Sun-4, which represented a key milestone in the company's history. The Sun-4 architecture, launched in 1987, utilized the SPARC (Scalable Processor Architecture) RISC processor, notable for its high performance and scalability.

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