Package org.cqframework.cql.elm.execution

Class Equal

java.lang.Object
org.opencds.cqf.cql.engine.elm.execution.Executable
org.cqframework.cql.elm.execution.Element
org.cqframework.cql.elm.execution.Expression
org.cqframework.cql.elm.execution.OperatorExpression
org.cqframework.cql.elm.execution.BinaryExpression
org.cqframework.cql.elm.execution.Equal
All Implemented Interfaces:
org.jvnet.jaxb2_commons.lang.Equals2, org.jvnet.jaxb2_commons.lang.HashCode2, org.jvnet.jaxb2_commons.lang.ToString2
Direct Known Subclasses:
EqualEvaluator
public class Equal extends BinaryExpression implements org.jvnet.jaxb2_commons.lang.Equals2, org.jvnet.jaxb2_commons.lang.HashCode2, org.jvnet.jaxb2_commons.lang.ToString2
The Equal operator returns true if the arguments are equal; false if the arguments are known unequal, and null otherwise. Equality semantics are defined to be value-based. For simple types, this means that equality returns true if and only if the result of each argument evaluates to the same value. For string values, equality is strictly lexical based on the Unicode values for the individual characters in the strings. For decimal values, trailing zeroes are ignored. For quantities, this means that the dimensions of each quantity must be the same, but not necessarily the unit. For example, units of 'cm' and 'm' are comparable, but units of 'cm2' and 'cm' are not. Attempting to operate on quantities with invalid units will result in null. When a quantity has no units specified, it is treated as a quantity with the default unit ('1'). For time-valued quantities, UCUM definite-time duration quantities above days (and weeks) are not comparable to calendar duration quantities above days (and weeks). Definite-time duration unit conversions shall be performed as specified in ISO-8601, while calendar-time duration unit conversions shall be performed according to calendar duration semantics. In particular, unit conversion between variable length calendar durations (i.e. years and months) and definite-time durations (i.e. days or below) results in null. For ratios, this means that the numerator and denominator must be the same, using quantity equality semantics. For tuple types, this means that equality returns true if and only if the tuples are of the same type, and the values for all elements that have values, by name, are equal. For list types, this means that equality returns true if and only if the lists contain elements of the same type, have the same number of elements, and for each element in the lists, in order, the elements are equal using equality semantics, with the exception that null elements are considered equal. For interval types, equality returns true if and only if the intervals are over the same point type, and they have the same value for the starting and ending points of the interval as determined by the Start and End operators. For Date, Time, and DateTime values, the comparison is performed by considering each precision in order, beginning with years (or hours for time values). If the values are the same, comparison proceeds to the next precision; if the values are different, the comparison stops and the result is false. If one input has a value for the precision and the other does not, the comparison stops and the result is null; if neither input has a value for the precision or the last precision has been reached, the comparison stops and the result is true. For the purposes of comparison, seconds and milliseconds are combined as a single precision using a decimal, with decimal equality semantics. If either argument is null, the result is null.

Java class for Equal complex type.

The following schema fragment specifies the expected content contained within this class. 

 <complexType name="Equal">
   <complexContent>
     <extension base="{urn:hl7-org:elm:r1}BinaryExpression">
     </extension>
   </complexContent>
 </complexType>