Package org.apache.sis.util
Enum Class ComparisonMode
- All Implemented Interfaces:
- Serializable,- Comparable<ComparisonMode>,- Constable
Specifies the level of strictness when comparing two 
LenientComparable objects
 for equality. This enumeration allows users to specify which kind of differences can be
 tolerated between two objects: differences in implementation class, differences in
 some kinds of property, or slight difference in numerical values.
 This enumeration is ordered from stricter to more lenient levels:
- STRICT– All attributes of the compared objects shall be strictly equal.
- BY_CONTRACT– Only the attributes published in the interface contract need to be compared.
- IGNORE_METADATA– Only the attributes relevant to the object functionality are compared.
- APPROXIMATE– Only the attributes relevant to the object functionality are compared, with some tolerance threshold on numerical values.
- ALLOW_VARIANT– For objects not really equal but related (e.g. CRS using different axis order).
- DEBUG– Special mode for figuring out why two objects expected to be equal are not.
BY_CONTRACT level, then they should also be equal at the
 IGNORE_METADATA level but not necessarily at the STRICT level.- Since:
- 0.3
- See Also:
Defined in the sis-utility module
- 
Nested Class SummaryNested classes/interfaces inherited from class EnumEnum.EnumDesc<E extends Enum<E>>
- 
Enum Constant SummaryEnum ConstantsEnum ConstantDescriptionMost but not all attributes relevant to the object functionality are compared.Only the attributes relevant to the object functionality are compared, with some tolerance threshold on numerical values.Only the attributes published in some contract (typically a GeoAPI interface) need to be compared.Same asAPPROXIMATE, except that anAssertionErroris thrown if the two objects are not equal and assertions are enabled.Only the attributes relevant to the object functionality are compared.All attributes of the compared objects shall be strictly equal.
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Method SummaryModifier and TypeMethodDescriptionstatic ComparisonModeequalityLevel(Object o1, Object o2) If the two given objects are equal according one of the modes enumerated in this class, then returns that mode.booleanReturnstrueif this comparison uses a tolerance threshold.booleanReturnstrueif this comparison ignores metadata.static ComparisonModeReturns the enum constant of this class with the specified name.static ComparisonMode[]values()Returns an array containing the constants of this enum class, in the order they are declared.Methods inherited from class Enumclone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf
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Enum Constant Details- 
STRICTAll attributes of the compared objects shall be strictly equal. This comparison mode is equivalent to theObject.equals(Object)method, and must be compliant with the contract documented in that method. In particular, this comparison mode shall be consistent withObject.hashCode()and be symmetric (A.equals(B)impliesB.equals(A)).Implementation noteIn the SIS implementation, this comparison mode usually have the following characteristics (not always, this is only typical):- The objects being compared need to be the same implementation class.
- Private fields are compared directly instead of invoking public getter methods.
 - See Also:
 
- 
BY_CONTRACTOnly the attributes published in some contract (typically a GeoAPI interface) need to be compared. The implementation classes do not need to be the same and some private attributes may be ignored.Note that this comparison mode does not guaranteed Object.hashCode()consistency, neither comparison symmetry (i.e.A.equals(B)andB.equals(A)may return different results if theequalsmethods are implemented differently).Implementation noteIn the SIS implementation, this comparison mode usually have the following characteristics (not always, this is only typical):- The objects being compared need to implement the same GeoAPI interfaces.
- Public getter methods are used (no direct access to private fields).
 
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IGNORE_METADATAOnly the attributes relevant to the object functionality are compared. Attributes that are only informative can be ignored. This comparison mode is typically less strict thanBY_CONTRACT.Application to coordinate reference systemsIf the objects being compared areCoordinateReferenceSysteminstances, then only the properties relevant to the coordinate localization shall be compared. Metadata like the identifiers or the domain of validity, which have no impact on the coordinates being calculated, shall be ignored.Application to coordinate operationsIf the objects being compared areMathTransforminstances, then two transforms defined in a different way may be considered equivalent. For example, it is possible to define a Mercator projection in two different ways, as a "Mercator (1SP)" or as a "Mercator (2SP)" projection, each having their own set of parameters. TheSTRICTorBY_CONTRACTmodes shall consider two projections as equal only if their parameter values are strictly identical, while theIGNORE_METADATAmode can consider those objects as equivalent despite difference in the set of parameters, as long as coordinate transformations still produce the same results.Example: A "Mercator (2SP)" projection with a standard parallel value of 60° produces the same results than a "Mercator (1SP)" projection with a scale factor value of 0.5.
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APPROXIMATEOnly the attributes relevant to the object functionality are compared, with some tolerance threshold on numerical values.Application to coordinate operationsIf twoMathTransformobjects are considered equal according this mode, then for any given identical source position, the two compared transforms shall compute at least approximately the same target position. A small difference is tolerated between the target coordinates calculated by the two math transforms. How small is “small” is implementation dependent — the threshold cannot be specified in the current implementation, because of the non-linear nature of map projections.- Since:
- 1.0
 
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ALLOW_VARIANTMost but not all attributes relevant to the object functionality are compared. This comparison mode is equivalent toAPPROXIMATE, except that it ignores some attributes that may differ between objects not equal but related.The main purpose of this method is to verify if two Coordinate Reference Systems (CRS) are approximately equal ignoring axis order. Example: consider two geographic coordinate reference systems with the same attributes except axis order, where one CRS uses (latitude, longitude) axes and the other CRS uses (longitude, latitude) axes. All comparison modes (evenAPPROXIMATE) will consider those two CRS as different, except thisALLOW_VARIANTmode which will consider one CRS to be a variant of the other.- Since:
- 0.7
 
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DEBUGSame asAPPROXIMATE, except that anAssertionErroris thrown if the two objects are not equal and assertions are enabled. The exception message and stack trace help to locate which attributes are not equal. This mode is typically used in assertions like below:
 Note that a comparison inassert Utilities.deepEquals(object1, object2, ComparisonMode.DEBUG); DEBUGmode may still returnfalsewithout throwing an exception, since not all corner cases are tested. The exception is only intended to provide more details for some common cases.
 
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Method Details- 
valuesReturns an array containing the constants of this enum class, in the order they are declared.- Returns:
- an array containing the constants of this enum class, in the order they are declared
 
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valueOfReturns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)- Parameters:
- name- the name of the enum constant to be returned.
- Returns:
- the enum constant with the specified name
- Throws:
- IllegalArgumentException- if this enum class has no constant with the specified name
- NullPointerException- if the argument is null
 
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isIgnoringMetadatapublic boolean isIgnoringMetadata()Returnstrueif this comparison ignores metadata. This method currently returnstrueforIGNORE_METADATA,APPROXIMATEorDEBUGonly, but this list may be extended in future SIS versions.- Returns:
- whether this comparison ignore metadata.
- Since:
- 0.6
 
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isApproximatepublic boolean isApproximate()Returnstrueif this comparison uses a tolerance threshold. This method currently returnstrueforAPPROXIMATEorDEBUGonly, but this list may be extended in future SIS versions.- Returns:
- whether this comparison uses a tolerance threshold.
- Since:
- 1.0
 
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equalityLevelIf the two given objects are equal according one of the modes enumerated in this class, then returns that mode. Otherwise returnsnull.Note: this method never return the DEBUGmode.- Parameters:
- o1- the first object to compare, or- null.
- o2- the second object to compare, or- null.
- Returns:
- the most suitable comparison mode, or nullif the two given objects are not equal according any mode in this enumeration.
 
 
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