Package net.sf.saxon.value

Class StringValue

  • All Implemented Interfaces:
    java.lang.Iterable<AtomicValue>, AtomicSequence, GroundedValue, IdentityComparable, Item, Sequence, ConversionResult
    Direct Known Subclasses:
    AnyURIValue
    public class StringValue
extends AtomicValue
    An atomic value of type xs:string. This class is also used for types derived from xs:string. The StringValue class is also used for xs:untypedAtomic; a subclass is used for xs:anyURI values.

    Internally the value is held as a wrapper around a UnicodeString, which allows a variety of implementations

    The equals and compareTo methods support ordering in codepoint collation sequence.

    • Constructor Detail

      • StringValue

        protected StringValue()
        Protected constructor for use by subtypes

      • StringValue

        protected StringValue​(AtomicType typeLabel)
        Protected constructor for use by subtypes

      • StringValue

        public StringValue​(UnicodeString content)
        Construct an instance that wraps a supplied UnicodeString, with the default type xs:string
        Parameters:
        content - the UnicodeString to wrap

      • StringValue

        public StringValue​(UnicodeString content,
                   AtomicType type)
        Construct an instance that wraps a supplied UnicodeString, with a supplied atomic type
        Parameters:
        content - the UnicodeString to wrap
        type - the requested atomic type

      • StringValue

        public StringValue​(java.lang.String value)
        Constructor from String. Creates an instance of xs:string.
        Parameters:
        value - the String value.

      • StringValue

        public StringValue​(java.lang.String value,
                   AtomicType typeLabel)
        Constructor from String. Note that although a StringValue may wrap any kind of CharSequence (usually a String, but it can also be, for example, a StringBuffer), the caller is responsible for ensuring that the value is immutable.
        Parameters:
        value - the String value.
        typeLabel - the type of the value to be created. The caller must ensure that this is a type derived from xs:string and that the string is valid against this type.

    • Method Detail

      • makeUntypedAtomic

        public static StringValue makeUntypedAtomic​(UnicodeString value)
        Factory method for untyped atomic values
        Parameters:
        value - the string value
        Returns:
        a new untyped atomic value around this string

      • copyAsSubType

        public StringValue copyAsSubType​(AtomicType typeLabel)
        Create a copy of this atomic value, with a different type label
        Specified by:
        copyAsSubType in class AtomicValue
        Parameters:
        typeLabel - the type label of the new copy. The caller is responsible for checking that the value actually conforms to this type.
        Returns:
        the copied value

      • bmp

        public static StringValue bmp​(java.lang.String content)
        Construct a StringValue whose content is known to consist entirely of BMP characters (codepoints less than 65536, with no surrogate pairs)
        Parameters:
        content - the content of the string, which the caller guarantees to contain no surrogate pairs
        Returns:
        the corresponding StringValue

      • getPrimitiveType

        public BuiltInAtomicType getPrimitiveType()
        Determine the primitive type of the value. This delivers the same answer as getItemType().getPrimitiveItemType(). The primitive types are the 19 primitive types of XML Schema, plus xs:integer, xs:dayTimeDuration and xs:yearMonthDuration, and xs:untypedAtomic. For external objects, the result is AnyAtomicType.
        Specified by:
        getPrimitiveType in class AtomicValue
        Returns:
        the primitive type

      • makeStringValue

        public static StringValue makeStringValue​(java.lang.CharSequence value)
        Factory method. Unlike the constructor, this avoids creating a new StringValue in the case of a zero-length string (and potentially other strings, in future)
        Parameters:
        value - the String value. Null is taken as equivalent to "".
        Returns:
        the corresponding StringValue

      • getPrimitiveStringValue

        public UnicodeString getPrimitiveStringValue()
        Description copied from class: AtomicValue
        Convert the value to a string, using the serialization rules for the primitive type. This is the result of conversion to a string except that postprocessing defined by the saxon:preprocess facet is not (yet) applied.
        Specified by:
        getPrimitiveStringValue in class AtomicValue
        Returns:
        the value converted to a string according to the rules for the primitive type

      • getContent

        public UnicodeString getContent()
        Get the content of this StringValue
        Returns:
        the content

      • length

        public long length()
        Get the length of this string, in code points
        Returns:
        the length of the string in Unicode code points

      • length32

        public int length32()
        Get the length of this string, in code points
        Returns:
        the length of the string in Unicode code points, provided that it is less than 2^31
        Throws:
        java.lang.UnsupportedOperationException - if the string contains more than 2^31 code points

      • isEmpty

        public boolean isEmpty()
        Determine whether the string is a zero-length string. This may be more efficient than testing whether the length is equal to zero
        Returns:
        true if the string is zero length

      • iterateCharacters

        public AtomicIterator iterateCharacters()
        Iterate over a string, returning a sequence of integers representing the Unicode code-point values
        Returns:
        an iterator over the characters (Unicode code points) in the string

      • getXPathMatchKey

        public AtomicMatchKey getXPathMatchKey​(StringCollator collator,
                                       int implicitTimezone)
        Get an object value that implements the XPath equality and ordering comparison semantics for this value. A context argument is supplied for use in cases where the comparison semantics are context-sensitive, for example where they depend on the implicit timezone or the default collation.
        Specified by:
        getXPathMatchKey in class AtomicValue
        Parameters:
        collator - Collation to be used for comparing strings
        implicitTimezone - the XPath dynamic evaluation context, used in cases where the comparison is context sensitive
        Returns:
        an Object whose equals() and hashCode() methods implement the XPath comparison semantics with respect to this atomic value. If ordered is specified, the result will either be null if no ordering is defined, or will be a Comparable

      • getCodepointCollationKey

        public Base64BinaryValue getCodepointCollationKey()
        Get an atomic value that encapsulates this match key. Needed to support the collation-key() function.
        Returns:
        an atomic value that encapsulates this match key

      • codePoints

        public IntIterator codePoints()
        Get an iterator over the Unicode codepoints in the value. These will always be full codepoints, never surrogates (surrogate pairs are combined where necessary).
        Returns:
        a sequence of Unicode codepoints

      • hashCode

        public int hashCode()
        Description copied from class: AtomicValue
        Returns a hash code value for the object.
        Overrides:
        hashCode in class AtomicValue

      • equals

        public boolean equals​(java.lang.Object o)
        Test whether this StringValue is equal to another under the rules of the codepoint collation. The type annotation is ignored.
        Overrides:
        equals in class AtomicValue
        Parameters:
        o - the value to be compared with this value
        Returns:
        true if the strings are equal on a codepoint-by-codepoint basis

      • toString

        public java.lang.String toString()
        Display as a string. In general toString() for an atomic value displays the value as it would be written in XPath: so this method returns the string with delimiting quotes.
        Overrides:
        toString in class AtomicValue
        See Also:
        getUnicodeStringValue()

      • toShortString

        public java.lang.String toShortString()
        Description copied from interface: Item
        Provide a short string showing the contents of the item, suitable for use in error messages
        Specified by:
        toShortString in interface GroundedValue
        Specified by:
        toShortString in interface Item
        Overrides:
        toShortString in class AtomicValue
        Returns:
        a depiction of the item suitable for use in error messages

      • getXPathComparable

        public XPathComparable getXPathComparable​(StringCollator collator,
                                          int implicitTimezone)
                                   throws NoDynamicContextException
        Description copied from class: AtomicValue
        Get an object value that implements the XPath equality and ordering comparison semantics for this value. A collation is supplied for comparing strings, and an implicit timezone for comparing date/time values that have no saved timezone. An atomic value may return itself as the result, provided that its ordering rules are independent of the collation and timezone, and provided that it implements the XPathComparable interface: which means that its compareTo, equals, and hashCode methods must be compatible with the rules for XPath value comparisons.
        Specified by:
        getXPathComparable in class AtomicValue
        Parameters:
        collator - the collation to be used when comparing strings
        implicitTimezone - the implicit timezone in the dynamic context, used when comparing dates/times with and without timezone
        Returns:
        an Object that implements the XPath value comparison semantics with respect to this atomic value. For an atomic type that is not ordered (according to XPath rules), return null.
        Throws:
        NoDynamicContextException - if the supplied implicit timezone is "NO_TIMEZONE" (meaning unknown), and the implicit timezone is actually required because the value in question is a date/time value with no timezone. This can cause a failure to evaluate expressions statically (because the implicit timezone is not known statically), and it will then be caught, meaning that the expression has to be evaluated dynamically.

      • isIdentical

        public boolean isIdentical​(AtomicValue v)
        Determine whether two atomic values are identical, as determined by XML Schema rules. This is a stronger test than equality (even schema-equality); for example two dateTime values are not identical unless they are in the same timezone.

        Note that even this check ignores the type annotation of the value. The integer 3 and the short 3 are considered identical, even though they are not fully interchangeable. "Identical" means the same point in the value space, regardless of type annotation.

        NaN is identical to itself.

        Overrides:
        isIdentical in class AtomicValue
        Parameters:
        v - the other value to be compared with this one
        Returns:
        true if the two values are identical, false otherwise.