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Altova UModel 2020 Professional Edition

Combined fragments ic-comb-frag are subunits, or sections of an interaction. The interaction operator visible in the pentagon at top left, defines the specific kind of combined fragment. The constraint thus defines the specific fragment, e.g. loop fragment, alternative fragment etc. used in the interaction.

sd-combfr1

The combined fragment icons in the icon bar allow you to insert a specific combined fragment: seq, alt or loop. Clicking the interactionOperator combo box also allows you to define the specific interaction fragment.

sd-combfr1a

 

InteractionOperators

Weak sequencing

seq ic-comb-frag

comb-fgmt-seq

 

The combined fragment represents weak sequencing between the behaviours of the operands.

Alternatives

alt ic-comb-frag-alt

Only one of the defined operands will be chosen, the operand must have a guard expression that evaluates to true.

comb-fgmt-alt

If one of the operands uses the guard "else", then this operand is executed if all other guards return false. The guard expression can be entered immediately upon insertion, will appear between the two square brackets.

comb-fgmt-IntUse

The InteractionConstraint is actually the guard expression between the square brackets.

Option

 

opt

Option represents a choice where either the sole operand is executed, or nothing happens.

Break

 

break

The break operator is chosen when the guard is true, the rest of the enclosing fragment is ignored.

Parallel

par

Indicates that the combined fragment represents a parallel merge of operands.

Strict sequencing

strict

The combined fragment represents a strict sequencing between the behaviours of the operands.

Loop

loop ic-comb-frag-loof

 

The loop operand will be repeated by the number of times defined in the guard expression.

 

comb-fgmt-loop

 

Having selected this operand, you can directly edit the expression (in the loop pentagon) by double clicking.

Critical Region

critical

The combined fragment represents a critical region. The sequence(s) may not be interrupted/interleaved by any other processes.

Negative

neg

Defines that the fragment is invalid, and all others are considered to be valid.

Assert

assert

Designates the valid combined fragment, and its sequences. Often used in combination with consider, or ignore operands.

Ignore

ignore

Defines which messages should be ignored in the interaction. Often used in combination with assert, or consider operands.

Consider

consider

Defines which messages should be considered in the interaction.

 

Adding InteractionOperands to a combined fragment

1.Right-click the combined fragment and select New | InteractionOperand. The text cursor is automatically set for you to enter the guard condition.

2.Enter the guard condition for the InteractionOperand e.g. !passwordOK and press Enter to confirm. Use Ctrl+Enter to create a multi-line InteractionOperand.

sd-combfr2

3.Use the same method to add the second interaction operand with the guard condition "else". Dashed lines separate the individual operands in the fragment.

 

Deleting InteractionOperands

1.Double-click the guard expression in the combined fragment element, of the diagram (not in the Properties tab).

2.Delete the guard expression completely, and press Enter to confirm. The guard expression/interaction operand is removed and the combined fragment is automatically resized.

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