Class Instruction


  • public class Instruction
    extends java.lang.Object
    Execution status of a single bytecode instruction internally used for coverage analysis. The execution status is recorded separately for each outgoing branch. Each instruction has at least one branch, for example in case of a simple sequence of instructions (by convention branch 0). Instances of this class are used in two steps:

    Step 1: Building the CFG

    For each bytecode instruction of a method a Instruction instance is created. In correspondence with the CFG these instances are linked with each other with the addBranch() methods. The executions status is either directly derived from a probe which has been inserted in the execution flow (addBranch(boolean, int)) or indirectly propagated along the CFG edges (addBranch(Instruction, int)).

    Step 2: Querying the Coverage Status

    After all instructions have been created and linked each instruction knows its execution status and can be queried with: For the purpose of filtering instructions can be combined to new instructions. Note that these methods create new Instruction instances and do not modify the existing ones.
    • Constructor Summary

      Constructors 
      Constructor Description
      Instruction​(int line)
      New instruction at the given line.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void addBranch​(boolean executed, int branch)
      Adds a branch to this instruction which execution status is directly derived from a probe.
      void addBranch​(Instruction target, int branch)
      Adds a branch to this instruction which execution status is indirectly derived from the execution status of the target instruction.
      ICounter getBranchCounter()
      Returns the branch coverage counter of this instruction.
      ICounter getInstructionCounter()
      Returns the instruction coverage counter of this instruction.
      int getLine()
      Returns the source line this instruction belongs to.
      Instruction merge​(Instruction other)
      Merges information about covered branches of this instruction with another instruction.
      Instruction replaceBranches​(java.util.Collection<Instruction> newBranches)
      Creates a copy of this instruction where all outgoing branches are replaced with the given instructions.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • Instruction

        public Instruction​(int line)
        New instruction at the given line.
        Parameters:
        line - source line this instruction belongs to
    • Method Detail

      • addBranch

        public void addBranch​(Instruction target,
                              int branch)
        Adds a branch to this instruction which execution status is indirectly derived from the execution status of the target instruction. In case the branch is covered the status is propagated also to the predecessors of this instruction. Note: This method is not idempotent and must be called exactly once for every branch.
        Parameters:
        target - target instruction of this branch
        branch - branch identifier unique for this instruction
      • addBranch

        public void addBranch​(boolean executed,
                              int branch)
        Adds a branch to this instruction which execution status is directly derived from a probe. In case the branch is covered the status is propagated also to the predecessors of this instruction. Note: This method is not idempotent and must be called exactly once for every branch.
        Parameters:
        executed - whether the corresponding probe has been executed
        branch - branch identifier unique for this instruction
      • getLine

        public int getLine()
        Returns the source line this instruction belongs to.
        Returns:
        corresponding source line
      • merge

        public Instruction merge​(Instruction other)
        Merges information about covered branches of this instruction with another instruction.
        Parameters:
        other - instruction to merge with
        Returns:
        new instance with merged branches
      • replaceBranches

        public Instruction replaceBranches​(java.util.Collection<Instruction> newBranches)
        Creates a copy of this instruction where all outgoing branches are replaced with the given instructions. The coverage status of the new instruction is derived from the status of the given instructions.
        Parameters:
        newBranches - new branches to consider
        Returns:
        new instance with replaced branches
      • getInstructionCounter

        public ICounter getInstructionCounter()
        Returns the instruction coverage counter of this instruction. It is always 1 instruction which is covered or not.
        Returns:
        the instruction coverage counter
      • getBranchCounter

        public ICounter getBranchCounter()
        Returns the branch coverage counter of this instruction. Only instructions with at least 2 outgoing edges report branches.
        Returns:
        the branch coverage counter