Object
- Invariant
- - UnaryInvariant
  - - SingleScalar
    - - NonZero

All Implemented Interfaces:

Serializable, Cloneable
```
public class NonZero
extends SingleScalar
```
Represents long scalars that are non-zero. Prints as x != 0, or as x != null for pointer types.

See Also:

Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class Invariant
  Invariant.ClassVarnameComparator, Invariant.ClassVarnameFormulaComparator, Invariant.InvariantComparatorForPrinting, Invariant.Match

Field Summary

Fields
Modifier and Type Field Description

static Logger debug
Debug tracer.

static boolean dkconfig_enabled
Boolean.
- Fields inherited from class Invariant
  checkedMergeOverridden, CONFIDENCE_JUSTIFIED, CONFIDENCE_NEVER, CONFIDENCE_UNJUSTIFIED, debugFlow, debugGuarding, debugIsObvious, debugIsWorthPrinting, debugPrint, debugPrintEquality, dkconfig_confidence_limit, dkconfig_fuzzy_ratio, dkconfig_simplify_define_predicates, falsified, invariantEnabledDefault, isGuardingPredicate, min_mod_non_missing_samples, ppt, PROBABILITY_JUSTIFIED, PROBABILITY_NEVER, PROBABILITY_UNJUSTIFIED

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`InvariantStatus`	`add_modified(long v, int count)`	Similar to `SingleScalar.check_modified(long, int)` except that it can change the state of the invariant if necessary.
`InvariantStatus`	`check_modified(long v, int count)`	Presents a sample to the invariant.
`protected double`	`computeConfidence()`	This method computes the confidence that this invariant occurred by chance.
`protected double`	`computeProbability()`
`boolean`	`enabled()`	Returns whether or not this class of invariants is currently enabled.
`String`	`format_using(OutputFormat format)`	Return a printed representation of this invariant, in the given format.
`static NonZero`	`get_proto()`	Returns the prototype invariant for NonZero
`NonZero`	`instantiate_dyn(PptSlice slice)`	Instantiates (creates) an invariant of the same class on the specified slice.
`boolean`	`instantiate_ok(VarInfo[] vis)`	Returns true if it makes sense to instantiate this invariant over the specified variables.
`boolean`	`isExclusiveFormula(Invariant other)`	Returns true iff the two invariants represent mutually exclusive mathematical formulas -- that is, if one of them is true, then the other must be false.
`@Nullable DiscardInfo`	`isObviousDynamically(VarInfo[] vis)`	Return non-null if this invariant is necessarily true from a fact that can be determined dynamically (after checking data) -- for the given varInfos rather than the varInfos of this.
`@Nullable DiscardInfo`	`isObviousStatically(VarInfo[] vis)`	Return true if this invariant is necessarily true from a fact that can be determined statically -- for the given varInfos rather than the varInfos of this.
`boolean`	`isSameFormula(Invariant other)`	Returns true iff the two invariants represent the same mathematical formula.

Methods inherited from class SingleScalar
add, add_unmodified, check, check_unmodified, valid_types, valid_types_static, var

Methods inherited from class UnaryInvariant
resurrect_done

Methods inherited from class Invariant
add_sample, asInvClass, checkRep, clear_falsified, clone, clone_and_permute, conf_is_ge, confidence_and, confidence_and, confidence_or, createGuardedInvariant, createGuardingPredicate, enoughSamples, falsify, find, format, format_classname, format_too_few_samples, format_unimplemented, formatFuzzy, get_comparability, get_ni_suppressions, getConfidence, getGuardingList, getGuardingList, hasUninterestingConstant, instantiate, is_false, is_ni_suppressed, isActive, isAllPrestate, isEqualityComparison, isExact, isObvious, isObviousDynamically, isObviousDynamically_SomeInEquality, isObviousDynamically_SomeInEqualityHelper, isObviousStatically, isObviousStatically_AllInEquality, isObviousStatically_SomeInEquality, isObviousStatically_SomeInEqualityHelper, isReflexive, isSameInvariant, isValidEscExpression, isValidExpression, isWorthPrinting, justified, log, log, logDetail, logOn, match, merge, mergeFormulasOk, permute, prob_and, prob_and, prob_is_ge, prob_or, repCheck, repr, repr_prob, resurrect, simplify_format_double, simplify_format_long, simplify_format_string, state_match, toString, toString, transfer, usesVar, usesVar, usesVarDerived, varNames

Methods inherited from class Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - dkconfig_enabled
```
public static boolean dkconfig_enabled
```
    Boolean. True iff NonZero invariants should be considered.
  - debug
```
public static final Logger debug
```
    Debug tracer.
- Method Detail
  - get_proto
```
public static NonZero get_proto()
```
    Returns the prototype invariant for NonZero
  - enabled
```
public boolean enabled()
```
    Description copied from class: Invariant
    
    Returns whether or not this class of invariants is currently enabled.
    Its implementation is almost always return dkconfig_enabled;.
    
    Specified by:
    
    enabled in class Invariant
  - instantiate_ok
```
public boolean instantiate_ok(VarInfo[] vis)
```
    Description copied from class: Invariant
    
    Returns true if it makes sense to instantiate this invariant over the specified variables. Checks details beyond what is provided by Invariant.valid_types(daikon.VarInfo[]). This should never be called without calling valid_types() first (implementations should be able to presume that valid_types() returns true).
    This method does not have to be overridden; the default implementation in Invariant returns true.
    
    Overrides:
    
    instantiate_ok in class Invariant
    
    See Also:
    
    Invariant.valid_types(VarInfo[])
  - instantiate_dyn
```
public NonZero instantiate_dyn( NonZero this,
                               PptSlice slice)
```
    Description copied from class: Invariant
    
    Instantiates (creates) an invariant of the same class on the specified slice. Must be overridden in each class. Must be used rather than Invariant.clone() so that checks in Invariant.instantiate(daikon.PptSlice) for reasonable invariants are done.
    The implementation of this method is almost always return new <em>InvName</em>(slice);
    
    Specified by:
    
    instantiate_dyn in class Invariant
    
    Returns:
    
    the new invariant
  - format_using
```
@SideEffectFree
public String format_using(@GuardSatisfied NonZero this,
                           OutputFormat format)
```
    Description copied from class: Invariant
    
    Return a printed representation of this invariant, in the given format.
    
    Specified by:
    
    format_using in class Invariant
  - check_modified
```
public InvariantStatus check_modified(long v,
                                      int count)
```
    Description copied from class: SingleScalar
    
    Presents a sample to the invariant. Returns whether the sample is consistent with the invariant. Does not change the state of the invariant.
    
    Specified by:
    
    check_modified in class SingleScalar
    
    count - how many identical samples were observed in a row. For example, three calls to check_modified with a count parameter of 1 is equivalent to one call to check_modified with a count parameter of 3.
    
    Returns:
    
    whether or not the sample is consistent with the invariant
  - add_modified
```
public InvariantStatus add_modified(long v,
                                    int count)
```
    Description copied from class: SingleScalar
    
    Similar to SingleScalar.check_modified(long, int) except that it can change the state of the invariant if necessary. If the invariant doesn't have any state, then the implementation should simply call SingleScalar.check_modified(long, int). This method need not check for falsification; that is done by the caller.
    
    Specified by:
    
    add_modified in class SingleScalar
  - computeConfidence
```
protected double computeConfidence()
```
    Description copied from class: Invariant
    
    This method computes the confidence that this invariant occurred by chance. Clients should call Invariant.getConfidence() instead.
    This method need not check the value of field "falsified", as the caller does that.
    
    Specified by:
    
    computeConfidence in class Invariant
    
    Returns:
    
    confidence of this invariant
    
    See Also:
    
    Invariant.getConfidence()
  - computeProbability
```
protected double computeProbability()
```
  - isObviousStatically
```
@Pure
public @Nullable DiscardInfo isObviousStatically(VarInfo[] vis)
```
    Description copied from class: Invariant
    
    Return true if this invariant is necessarily true from a fact that can be determined statically -- for the given varInfos rather than the varInfos of this. Conceptually, this means "is this invariant statically obvious if its VarInfos were switched with vis?" Intended to be overridden by subclasses. Should only do static checking.
    Precondition: vis.length == this.ppt.var_infos.length
    
    Overrides:
    
    isObviousStatically in class Invariant
    
    Parameters:
    
    vis - the VarInfos this invariant is obvious over. The position and data type of the variables is the *same* as that of this.ppt.var_infos.
  - isObviousDynamically
```
@Pure
public @Nullable DiscardInfo isObviousDynamically(VarInfo[] vis)
```
    Description copied from class: Invariant
    
    Return non-null if this invariant is necessarily true from a fact that can be determined dynamically (after checking data) -- for the given varInfos rather than the varInfos of this. Conceptually, this means, "Is this invariant dynamically obvious if its VarInfos were switched with vis?" Intended to be overriden by subclasses so they can filter invariants after checking; the overriding method should first call "super.isObviousDynamically(vis)". Since this method is dynamic, it should only be called after all processing.
    
    Overrides:
    
    isObviousDynamically in class Invariant
  - isSameFormula
```
@Pure
public boolean isSameFormula(Invariant other)
```
    Description copied from class: Invariant
    
    Returns true iff the two invariants represent the same mathematical formula. Does not consider the context such as variable names, confidences, sample counts, value counts, or related quantities. As a rule of thumb, if two invariants format the same, this method returns true. Furthermore, in many cases, if an invariant does not involve computed constants (as "x>c" and "y=ax+b" do for constants a, b, and c), then this method vacuously returns true.
    
    Specified by:
    
    isSameFormula in class Invariant
    
    Parameters:
    
    other - the invariant to compare to this one
    
    Returns:
    
    true iff the two invariants represent the same mathematical formula. Does not consider
  - isExclusiveFormula
```
@Pure
public boolean isExclusiveFormula(Invariant other)
```
    Description copied from class: Invariant
    
    Returns true iff the two invariants represent mutually exclusive mathematical formulas -- that is, if one of them is true, then the other must be false. This method does not consider the context such as variable names, confidences, sample counts, value counts, or related quantities.
    
    Overrides:
    
    isExclusiveFormula in class Invariant
    
    Parameters:
    
    other - the other invariant to compare to this one
    
    Returns:
    
    true iff the two invariants represent mutually exclusive mathematical formulas

Modifier and Type	Field	Description
`static Logger`	`debug`	Debug tracer.
`static boolean`	`dkconfig_enabled`	Boolean.

Class NonZero

Nested Class Summary

Nested classes/interfaces inherited from class Invariant

Field Summary

Fields inherited from class Invariant

Method Summary

Methods inherited from class SingleScalar

Methods inherited from class UnaryInvariant

Methods inherited from class Invariant

Methods inherited from class Object

Field Detail

dkconfig_enabled

debug

Method Detail

get_proto

enabled

instantiate_ok

instantiate_dyn

format_using

check_modified

add_modified

computeConfidence

computeProbability

isObviousStatically

isObviousDynamically

isSameFormula

isExclusiveFormula