Package net.sf.saxon.value
Class StringValue
- java.lang.Object
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- net.sf.saxon.value.Value<AtomicValue>
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- net.sf.saxon.value.AtomicValue
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- net.sf.saxon.value.StringValue
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- All Implemented Interfaces:
PullEvent
,GroundedValue<AtomicValue>
,Item<AtomicValue>
,ValueRepresentation<AtomicValue>
,ConversionResult
- Direct Known Subclasses:
AnyURIValue
,UntypedAtomicValue
public class StringValue extends AtomicValue
An atomic value of type xs:string. This class is also used for types derived from xs:string. Subclasses of StringValue are used for xs:untypedAtomic and xs:anyURI values.
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Nested Class Summary
Nested Classes Modifier and Type Class Description class
StringValue.CharacterIterator
CharacterIterator is used to iterate over the characters in a string, returning them as integers representing the Unicode code-point.
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Field Summary
Fields Modifier and Type Field Description static StringValue
EMPTY_STRING
static StringValue
FALSE
protected boolean
noSurrogates
static StringValue
SINGLE_SPACE
static StringValue
TRUE
protected java.lang.CharSequence
value
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Fields inherited from class net.sf.saxon.value.AtomicValue
typeLabel
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Fields inherited from class net.sf.saxon.value.Value
INDETERMINATE_ORDERING
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Fields inherited from interface net.sf.saxon.om.ValueRepresentation
EMPTY_VALUE_ARRAY
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Constructor Summary
Constructors Modifier Constructor Description protected
StringValue()
Protected constructor for use by subtypesStringValue(java.lang.CharSequence value)
Constructor.StringValue(java.lang.CharSequence value, AtomicType typeLabel)
Constructor.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
codepointEquals(StringValue other)
Test whether this StringValue is equal to another under the rules of the codepoint collationboolean
containsSurrogatePairs()
Determine whether the string contains surrogate pairsstatic java.lang.CharSequence
contract(int[] codes, int used)
Contract an array of integers containing Unicode codepoints into a Java stringAtomicValue
copyAsSubType(AtomicType typeLabel)
Create a copy of this atomic value, with a different type labelstatic java.lang.String
diagnosticDisplay(java.lang.String s)
Produce a diagnostic representation of the contents of the stringboolean
effectiveBooleanValue()
Get the effective boolean value of a stringboolean
equals(java.lang.Object other)
Determine if two AtomicValues are equal, according to XPath rules.int[]
expand()
Expand a string containing surrogate pairs into an array of 32-bit charactersstatic int[]
expand(java.lang.CharSequence s)
Expand a string containing surrogate pairs into an array of 32-bit charactersjava.lang.CharSequence
getPrimitiveStringValue()
Get the string value as a CharSequenceBuiltInAtomicType
getPrimitiveType()
Determine the primitive type of the value.java.lang.Comparable
getSchemaComparable()
Get a Comparable value that implements the XML Schema comparison semantics for this value.int
getStringLength()
Get the length of this string, as defined in XPath.static int
getStringLength(java.lang.CharSequence s)
Get the length of a string, as defined in XPath.java.lang.Object
getXPathComparable(boolean ordered, StringCollator collator, XPathContext context)
Get an object value that implements the XPath equality and ordering comparison semantics for this value.int
hashCode()
boolean
isIdentical(Value v)
Determine whether two atomic values are identical, as determined by XML Schema rules.boolean
isKnownToContainNoSurrogates()
Ask whether the string is known to contain no surrogate pairs.boolean
isZeroLength()
Determine whether the string is a zero-length string.UnfailingIterator
iterateCharacters()
Iterate over a string, returning a sequence of integers representing the Unicode code-point valuesstatic StringValue
makeStringValue(java.lang.CharSequence value)
Factory method.void
setContainsNoSurrogates()
Assert that the string is known to contain no surrogate pairsvoid
setStringValueCS(java.lang.CharSequence value)
Set the value of the item as a CharSequence.java.lang.String
toString()
Get string value.-
Methods inherited from class net.sf.saxon.value.AtomicValue
asAtomic, checkPermittedContents, getCardinality, getComponent, getItemType, getLength, getStringValue, getStringValueCS, getTypedValue, getTypeLabel, isNaN, itemAt, iterate, process, setTypeLabel, subsequence
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Methods inherited from class net.sf.saxon.value.Value
asItem, asItem, asIterator, asValue, convertToJava, fromItem, getCanonicalLexicalRepresentation, getIterator, getSequenceLength, reduce
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Field Detail
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EMPTY_STRING
public static final StringValue EMPTY_STRING
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SINGLE_SPACE
public static final StringValue SINGLE_SPACE
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TRUE
public static final StringValue TRUE
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FALSE
public static final StringValue FALSE
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value
protected java.lang.CharSequence value
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noSurrogates
protected boolean noSurrogates
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Constructor Detail
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StringValue
protected StringValue()
Protected constructor for use by subtypes
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StringValue
public StringValue(java.lang.CharSequence value)
Constructor. 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. Null is taken as equivalent to "".
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StringValue
public StringValue(java.lang.CharSequence value, AtomicType typeLabel)
Constructor. 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 string and that the string is valid against this type.
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Method Detail
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setContainsNoSurrogates
public void setContainsNoSurrogates()
Assert that the string is known to contain no surrogate pairs
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copyAsSubType
public AtomicValue copyAsSubType(AtomicType typeLabel)
Create a copy of this atomic value, with a different type label- Specified by:
copyAsSubType
in classAtomicValue
- 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
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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 classAtomicValue
- Returns:
- the primitive type
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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
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getPrimitiveStringValue
public final java.lang.CharSequence getPrimitiveStringValue()
Get the string value as a CharSequence- Specified by:
getPrimitiveStringValue
in classAtomicValue
- Returns:
- the value converted to a string according to the rules for the primitive type
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setStringValueCS
public final void setStringValueCS(java.lang.CharSequence value)
Set the value of the item as a CharSequence.For system use only. In principle, a StringValue is immutable. However, in special circumstances, if it is newly constructed, the content can be changed to reflect the effect of the whiteSpace facet.
- Parameters:
value
- the value of the string
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getStringLength
public int getStringLength()
Get the length of this string, as defined in XPath. This is not the same as the Java length, as a Unicode surrogate pair counts as a single character- Returns:
- the length of the string in Unicode code points
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getStringLength
public static int getStringLength(java.lang.CharSequence s)
Get the length of a string, as defined in XPath. This is not the same as the Java length, as a Unicode surrogate pair counts as a single character.- Parameters:
s
- The string whose length is required- Returns:
- the length of the string in Unicode code points
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isZeroLength
public boolean isZeroLength()
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
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containsSurrogatePairs
public boolean containsSurrogatePairs()
Determine whether the string contains surrogate pairs- Returns:
- true if the string contains any non-BMP characters
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isKnownToContainNoSurrogates
public boolean isKnownToContainNoSurrogates()
Ask whether the string is known to contain no surrogate pairs.- Returns:
- true if it is known to contain no surrogates, false if the answer is not known
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iterateCharacters
public UnfailingIterator 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
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expand
public int[] expand()
Expand a string containing surrogate pairs into an array of 32-bit characters- Returns:
- an array of integers representing the Unicode code points
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expand
public static int[] expand(java.lang.CharSequence s)
Expand a string containing surrogate pairs into an array of 32-bit characters- Parameters:
s
- the string to be expanded- Returns:
- an array of integers representing the Unicode code points
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contract
public static java.lang.CharSequence contract(int[] codes, int used)
Contract an array of integers containing Unicode codepoints into a Java string- Parameters:
codes
- an array of integers representing the Unicode code pointsused
- the number of items in the array that are actually used- Returns:
- the constructed string
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getXPathComparable
public java.lang.Object getXPathComparable(boolean ordered, StringCollator collator, XPathContext context)
Get an object value that implements the XPath equality and ordering comparison semantics for this value. If the ordered parameter is set to true, the result will be a Comparable and will support a compareTo() method with the semantics of the XPath lt/gt operator, provided that the other operand is also obtained using the getXPathComparable() method. In all cases the result will support equals() and hashCode() methods that support the semantics of the XPath eq operator, again provided that the other operand is also obtained using the getXPathComparable() method. 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:
getXPathComparable
in classAtomicValue
- Parameters:
ordered
- true if an ordered comparison is required. In this case the result is null if the type is unordered; in other cases the returned value will be a Comparable.collator
- Collation to be used for comparing stringscontext
- 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
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equals
public boolean equals(java.lang.Object other)
Determine if two AtomicValues are equal, according to XPath rules. (This method is not used for string comparisons, which are always under the control of a collation. If we get here, it's because there's a type error in the comparison.)- Specified by:
equals
in classAtomicValue
- Parameters:
other
- the other value- Returns:
- true if the other operand is an atomic value and the two values are equal as defined by the XPath eq operator
- Throws:
java.lang.ClassCastException
- always
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hashCode
public int hashCode()
- Overrides:
hashCode
in classValue<AtomicValue>
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codepointEquals
public boolean codepointEquals(StringValue other)
Test whether this StringValue is equal to another under the rules of the codepoint collation- Parameters:
other
- the value to be compared with this value- Returns:
- true if the strings are equal on a codepoint-by-codepoint basis
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effectiveBooleanValue
public boolean effectiveBooleanValue()
Get the effective boolean value of a string- Overrides:
effectiveBooleanValue
in classAtomicValue
- Returns:
- true if the string has length greater than zero
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toString
public java.lang.String toString()
Description copied from class:AtomicValue
Get string value. In general toString() for an atomic value displays the value as it would be written in XPath: that is, as a literal if available, or as a call on a constructor function otherwise.- Overrides:
toString
in classAtomicValue
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getSchemaComparable
public java.lang.Comparable getSchemaComparable()
Get a Comparable value that implements the XML Schema comparison semantics for this value. Returns null if the value is not comparable according to XML Schema rules. This implementation returns the underlying Java string, which works because strings will only be compared for equality, not for ordering, and the equality rules for strings in XML schema are the same as in Java.- Specified by:
getSchemaComparable
in classAtomicValue
- Returns:
- a Comparable that follows XML Schema comparison rules
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isIdentical
public boolean isIdentical(Value 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 classAtomicValue
- Parameters:
v
- the other value to be compared with this one- Returns:
- true if the two values are identical, false otherwise.
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diagnosticDisplay
public static java.lang.String diagnosticDisplay(java.lang.String s)
Produce a diagnostic representation of the contents of the string- Parameters:
s
- the string- Returns:
- a string in which non-Ascii-printable characters are replaced by \ uXXXX escapes
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