## net.sf.saxon.value
Class Cardinality

    java.lang.Object
      net.sf.saxon.value.Cardinality

    public final class Cardinality

extends java.lang.Object

This class contains static methods to manipulate the cardinality property of a type. Cardinality of expressions is denoted by one of the values ONE_OR_MORE, ZERO_OR_MORE, ZERO_OR_ONE, EXACTLY_ONE, or EMPTY. These are combinations of the three bit-significant values ALLOWS_ZERO, ALLOWS_ONE, and ALLOWS_MANY.

Method Summary
`static boolean` `allowsMany(int cardinality)` Determine whether multiple occurrences are allowed
`static boolean` `allowsZero(int cardinality)` Determine whether empty sequence is allowed
`static boolean` `expectsMany(Expression expression)` Determine whether multiple occurrences are not only allowed, but likely.
`static java.lang.String` `getOccurrenceIndicator(int cardinality)` Get the occurence indicator representing the cardinality
`static int` `multiply(int c1, int c2)` Multiply two cardinalities
`static boolean` `subsumes(int c1, int c2)` Test if one cardinality subsumes another.
`static int` `sum(int c1, int c2)` Add two cardinalities
`static java.lang.String` `toString(int cardinality)` Display the cardinality as a string
`static int` `union(int c1, int c2)` Form the union of two cardinalities.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Method Detail

### allowsMany

    public static boolean allowsMany(int cardinality)

  Determine whether multiple occurrences are allowed

  Parameters:
    `cardinality` - the cardinality of a sequence
  Returns:
    true if the cardinality allows the sequence to contain more than one item

### expectsMany

    public static boolean expectsMany(Expression expression)

  Determine whether multiple occurrences are not only allowed, but likely. This returns false for an expression that is the atomization of a singleton node, since in that case it's quite unusual for the typed value to be a non-singleton sequence.

  Parameters:
    `expression` - an expression
  Returns:
    true if multiple occurrences are not only allowed, but likely. Return false if multiple occurrences are unlikely, even though they might be allowed. This is typically the case for the atomized sequence that is obtained by atomizing a singleton node.

### allowsZero

    public static boolean allowsZero(int cardinality)

  Determine whether empty sequence is allowed

  Parameters:
    `cardinality` - the cardinality of a sequence
  Returns:
    true if the cardinality allows the sequence to be empty

### union

    public static int union(int c1,
                            int c2)

  Form the union of two cardinalities. The cardinality of the expression "if (c) then e1 else e2" is the union of the cardinalities of e1 and e2.

  Parameters:
    `c1` - a cardinality
    `c2` - another cardinality
  Returns:
    the cardinality that allows both c1 and c2

### sum

    public static int sum(int c1,
                          int c2)

  Add two cardinalities

  Parameters:
    `c1` - the first cardinality
    `c2` - the second cardinality
  Returns:
    the cardinality of a sequence formed by concatenating the sequences whose cardinalities are c1 and c2

### subsumes

    public static boolean subsumes(int c1,
                                   int c2)

  Test if one cardinality subsumes another. Cardinality c1 subsumes c2 if every option permitted by c2 is also permitted by c1.

  Parameters:
    `c1` - a cardinality
    `c2` - another cardinality
  Returns:
    true if if every option permitted by c2 is also permitted by c1.

### multiply

    public static int multiply(int c1,
                               int c2)

  Multiply two cardinalities

  Parameters:
    `c1` - the first cardinality
    `c2` - the second cardinality
  Returns:
    the product of the cardinalities, that is, the cardinality of the sequence "for $x in S1 return S2", where c1 is the cardinality of S1 and c2 is the cardinality of S2

### toString

    public static java.lang.String toString(int cardinality)

  Display the cardinality as a string

  Parameters:
    `cardinality` - the cardinality value to be displayed
  Returns:
    the representation as a string, for example "zero or one", "zero or more"

### getOccurrenceIndicator

    public static java.lang.String getOccurrenceIndicator(int cardinality)

  Get the occurence indicator representing the cardinality

  Parameters:
    `cardinality` - the cardinality value
  Returns:
    the occurrence indicator, for example "*", "+", "?", "".

Copyright (c) Saxonica Limited. All rights reserved.