net.sf.saxon.value
Class StringValue

java.lang.Object
  |
  +--net.sf.saxon.value.Value
        |
        +--net.sf.saxon.value.AtomicValue
              |
              +--net.sf.saxon.value.StringValue
All Implemented Interfaces:
Expression, Item, java.io.Serializable
Direct Known Subclasses:
RestrictedStringValue, UntypedAtomicValue

public class StringValue
extends AtomicValue

A string value

See Also:
Serialized Form

Nested Class Summary
 class StringValue.CharacterIterator
          CharacterIterator is used to iterate over the characters in a string, returning them as integers representing the Unicode code-point.
 
Field Summary
static StringValue EMPTY_STRING
           
protected  int length
           
protected  java.lang.CharSequence value
           
 
Constructor Summary
protected StringValue()
          Protected constructor for use by subtypes
  StringValue(java.lang.CharSequence value)
          Constructor.
 
Method Summary
 int conversionPreference(java.lang.Class required, Configuration config)
          Get conversion preference for this value to a Java class.
 AtomicValue convert(int requiredType)
          Convert to target data type
 java.lang.Object convertToJava(java.lang.Class target, Configuration config)
          Convert to Java object (for passing to external functions)
 void display(int level, NamePool pool)
          Diagnostic print of expression structure
 boolean effectiveBooleanValue(XPathContext context)
          Get the effective boolean value of the value
 boolean equals(java.lang.Object other)
          Determine if two StringValues are equal
static int[] expand(java.lang.CharSequence s)
          Expand a string containing surrogate pairs into an array of 32-bit characters
 ItemType getItemType()
          Return the type of the expression
 int getLength()
          Get the length of this string, as defined in XPath.
static int getLength(java.lang.CharSequence s)
          Get the length of a string, as defined in XPath.
 java.lang.String getStringValue()
          Get the string value as a String
 int hashCode()
           
 SequenceIterator iterateCharacters()
          Iterate over a string, returning a sequence of integers representing the Unicode code-point values
 java.lang.String toString()
           
 
Methods inherited from class net.sf.saxon.value.AtomicValue
convert, evaluateAsString, evaluateItem, getCardinality, getComponent, getPrimitiveValue, getTypedValue, iterate
 
Methods inherited from class net.sf.saxon.value.Value
analyze, asItem, asValue, collapseWhitespace, getDependencies, getSpecialProperties, getSubExpressions, inverse, normalizeWhitespace, promote, simplify, stringToNumber, trimWhitespace
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

EMPTY_STRING

public static final StringValue EMPTY_STRING

value

protected java.lang.CharSequence value

length

protected int length
Constructor Detail

StringValue

protected StringValue()
Protected constructor for use by subtypes


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 "".
Method Detail

getStringValue

public final java.lang.String getStringValue()
Get the string value as a String

Specified by:
getStringValue in interface Item
Specified by:
getStringValue in class Value
Returns:
the string value of the item

convert

public AtomicValue convert(int requiredType)
                    throws XPathException
Convert to target data type

Specified by:
convert in class AtomicValue
Parameters:
requiredType - an integer identifying the required atomic type
Returns:
an AtomicValue, a value of the required type
Throws:
XPathException - if the conversion is not possible

getItemType

public ItemType getItemType()
Return the type of the expression

Returns:
Type.STRING (always)

getLength

public int getLength()
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


getLength

public static int getLength(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

iterateCharacters

public SequenceIterator iterateCharacters()
Iterate over a string, returning a sequence of integers representing the Unicode code-point values


expand

public static int[] expand(java.lang.CharSequence s)
Expand a string containing surrogate pairs into an array of 32-bit characters


equals

public boolean equals(java.lang.Object other)
Determine if two StringValues are equal

Overrides:
equals in class java.lang.Object
Throws:
java.lang.ClassCastException - if the values are not comparable

hashCode

public int hashCode()
Overrides:
hashCode in class java.lang.Object

effectiveBooleanValue

public boolean effectiveBooleanValue(XPathContext context)
Description copied from class: AtomicValue
Get the effective boolean value of the value

Specified by:
effectiveBooleanValue in interface Expression
Overrides:
effectiveBooleanValue in class AtomicValue
Parameters:
context - the evaluation context (not used in this implementation)
Returns:
true, unless the value is boolean false, numeric zero, or zero-length string

conversionPreference

public int conversionPreference(java.lang.Class required,
                                Configuration config)
Get conversion preference for this value to a Java class. A low result indicates higher preference.

Overrides:
conversionPreference in class AtomicValue

convertToJava

public java.lang.Object convertToJava(java.lang.Class target,
                                      Configuration config)
                               throws XPathException
Convert to Java object (for passing to external functions)

Overrides:
convertToJava in class AtomicValue
Parameters:
target - The class required by the external function
config - The configuration (needed for access to schema information)
Returns:
an object of the target class
XPathException

display

public void display(int level,
                    NamePool pool)
Diagnostic print of expression structure

Parameters:
level - indentation level for this expression

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object