XML (Apache Derby V10.14 Internals)

java.lang.Object
- org.apache.derby.iapi.types.DataType
- - org.apache.derby.iapi.types.XML

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, java.lang.Comparable, Formatable, Storable, StreamStorable, TypedFormat, DataValueDescriptor, Orderable, XMLDataValue
```
public class XML
extends DataType
implements XMLDataValue, StreamStorable
```
This type implements the XMLDataValue interface and thus is the type on which all XML related operations are executed. The first and simplest XML store implementation is a UTF-8 based one--all XML data is stored on disk as a UTF-8 string, just like the other Derby string types. In order to make it possible for smarter XML implementations to exist in the future, this class always writes an "XML implementation id" to disk before writing the rest of its data. When reading the data, the impl id is read first and serves as an indicator of how the rest of the data should be read. So long as there's only one implementation (UTF-8) the impl id can be ignored; but when smarter implementations are written, the impl id will be the key to figuring out how an XML value should be read, written, and processed.

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`private static int`	`BASE_MEMORY_USAGE`
`private boolean`	`containsTopLevelAttr`
`private SqlXmlUtil`	`tmpUtil`
`protected static short`	`UTF8_IMPL_ID`
`static int`	`XML_DOC_ANY`
`static int`	`XML_SEQUENCE`
`private static java.lang.String`	`xmlReqCheck`
`private SQLChar`	`xmlStringValue`
`static short`	`XQ_EMPTY_ON_EMPTY`
`static short`	`XQ_NULL_ON_EMPTY`
`static short`	`XQ_PASS_BY_REF`
`static short`	`XQ_PASS_BY_VALUE`
`static short`	`XQ_RETURN_CONTENT`
`static short`	`XQ_RETURN_SEQUENCE`
`private int`	`xType`

Fields inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
UNKNOWN_LOGICAL_LENGTH

Fields inherited from interface org.apache.derby.iapi.types.Orderable
ORDER_OP_EQUALS, ORDER_OP_GREATEROREQUALS, ORDER_OP_GREATERTHAN, ORDER_OP_LESSOREQUALS, ORDER_OP_LESSTHAN

Constructor Summary

Constructors
Modifier	Constructor	Description
	`XML()`	Default constructor.
`private`	`XML(SQLChar val, int xmlType, boolean seqWithAttr, boolean materialize)`	Private constructor used for the `cloneValue` method.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`private static boolean`	`checkJAXPRequirement()`	Check if we have a JAXP implementation installed.
`static void`	`checkXMLRequirements()`	See if the required JAXP and Xalan classes are in the user's classpath.
`private static boolean`	`checkXPathRequirement()`	Check if XPath is supported on this platform.
`DataValueDescriptor`	`cloneValue(boolean forceMaterialization)`	Clone this DataValueDescriptor.
`int`	`compare(DataValueDescriptor other)`	Compare two XML DataValueDescriptors.
`int`	`estimateMemoryUsage()`	Estimate the memory usage in bytes of the data value and the overhead of the class.
`int`	`getLength()`	Gets the length of the data value.
`DataValueDescriptor`	`getNewNull()`	Get a new null value of the same type as this data value.
`java.lang.String`	`getString()`	Gets the value in the data value descriptor as a String.
`int`	`getTypeFormatId()`	Get a universally unique identifier for the type of this object.
`java.lang.String`	`getTypeName()`	Get the SQL name of the datatype
`int`	`getXType()`	Retrieve this XML value's qualified type.
`boolean`	`hasTopLevelAttr()`	Return whether or not this XML value represents a sequence that has one or more top-level attribute nodes.
`boolean`	`isNull()`	Return whether the value is null or not.
`void`	`loadStream()`	Set the value by reading the stream and converting it to an object form.
`void`	`markAsHavingTopLevelAttr()`	Take note of the fact this XML value represents an XML sequence that has one or more top-level attribute nodes.
`void`	`normalize(DataTypeDescriptor desiredType, DataValueDescriptor source)`	Normalization method - this method will always be called when storing an XML value into an XML column, for example, when inserting/updating.
`void`	`readExternal(java.io.ObjectInput in)`	Read an XML value from an input stream.
`void`	`readExternalFromArray(ArrayInputStream in)`	Read the DataValueDescriptor from the stream.
`void`	`restoreToNull()`	Restore this object to its (SQL)null value.
`java.io.InputStream`	`returnStream()`	Return the on-disk stream state of the object.
`protected void`	`setFrom(DataValueDescriptor theValue)`	Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
`void`	`setStream(java.io.InputStream newStream)`	sets the on-disk stream state for the object.
`void`	`setValueFromResultSet(java.sql.ResultSet resultSet, int colNumber, boolean isNullable)`	Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
`void`	`setXType(int xtype)`	Set this XML value's qualified type.
`int`	`typePrecedence()`	Each built-in type in JSQL has a precedence.
`void`	`writeExternal(java.io.ObjectOutput out)`	Write an XML value.
`BooleanDataValue`	`XMLExists(SqlXmlUtil sqlxUtil)`	The SQL/XML XMLExists operator.
`XMLDataValue`	`XMLParse(StringDataValue stringValue, boolean preserveWS, SqlXmlUtil sqlxUtil)`	Method to parse an XML string and, if it's valid, store the _serialized_ version locally and then return this XMLDataValue.
`XMLDataValue`	`XMLQuery(SqlXmlUtil sqlxUtil, XMLDataValue result)`	Evaluate the XML query expression contained within the received util object against this XML value and store the results into the received XMLDataValue "result" param (assuming "result" is non-null; else create a new XMLDataValue).
`StringDataValue`	`XMLSerialize(StringDataValue result, int targetType, int targetWidth, int targetCollationType)`	The SQL/XML XMLSerialize operator.

Methods inherited from class org.apache.derby.iapi.types.DataType
checkHostVariable, cloneHolder, coalesce, compare, compare, compare, compareTo, dataTypeConversion, equals, equals, flip, genericSetObject, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getObject, getShort, getStream, getTime, getTimestamp, getTraceString, getTypeName, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, notEquals, outOfRange, recycle, setBigDecimal, setInto, setInto, setObject, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, throwLangSetMismatch, typeToBigDecimal

Methods inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
checkHostVariable, cloneHolder, coalesce, compare, compare, compare, equals, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getObject, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, isNotNull, isNullOp, lessOrEquals, lessThan, notEquals, recycle, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, typeToBigDecimal

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

- Field Detail
  - UTF8_IMPL_ID
```
protected static final short UTF8_IMPL_ID
```
    See Also:
    
    Constant Field Values
  - BASE_MEMORY_USAGE
```
private static final int BASE_MEMORY_USAGE
```
  - XQ_PASS_BY_REF
```
public static final short XQ_PASS_BY_REF
```
    See Also:
    
    Constant Field Values
  - XQ_PASS_BY_VALUE
```
public static final short XQ_PASS_BY_VALUE
```
    See Also:
    
    Constant Field Values
  - XQ_RETURN_SEQUENCE
```
public static final short XQ_RETURN_SEQUENCE
```
    See Also:
    
    Constant Field Values
  - XQ_RETURN_CONTENT
```
public static final short XQ_RETURN_CONTENT
```
    See Also:
    
    Constant Field Values
  - XQ_EMPTY_ON_EMPTY
```
public static final short XQ_EMPTY_ON_EMPTY
```
    See Also:
    
    Constant Field Values
  - XQ_NULL_ON_EMPTY
```
public static final short XQ_NULL_ON_EMPTY
```
    See Also:
    
    Constant Field Values
  - XML_DOC_ANY
```
public static final int XML_DOC_ANY
```
    See Also:
    
    Constant Field Values
  - XML_SEQUENCE
```
public static final int XML_SEQUENCE
```
    See Also:
    
    Constant Field Values
  - xType
```
private int xType
```
  - xmlStringValue
```
private SQLChar xmlStringValue
```
  - xmlReqCheck
```
private static java.lang.String xmlReqCheck
```
  - containsTopLevelAttr
```
private boolean containsTopLevelAttr
```
  - tmpUtil
```
private SqlXmlUtil tmpUtil
```
- Constructor Detail
  - XML
```
public XML()
```
    Default constructor.
  - XML
```
private XML(SQLChar val,
            int xmlType,
            boolean seqWithAttr,
            boolean materialize)
```
    Private constructor used for the cloneValue method. Returns a new instance of XML whose fields are clones of the values received.
    
    Parameters:
    
    val - A SQLChar instance to clone and use for this XML value.
    
    xmlType - Qualified XML type for "val"
    
    seqWithAttr - Whether or not "val" corresponds to sequence with one or more top-level attribute nodes.
    
    materialize - whether or not to force materialization of the underlying source data
- Method Detail
  - cloneValue
```
public DataValueDescriptor cloneValue(boolean forceMaterialization)
```
    Description copied from interface: DataValueDescriptor
    
    Clone this DataValueDescriptor. Results in a new object that has the same value as this but can be modified independently.
    Even though the objects can be modified independently regardless of the value of forceMaterialization, both the clone and the original may be dependent on the store state if forceMaterialization is set to false. An example is if you need to access the value you just read using cloneValue after the current transaction has ended, or after the source result set has been closed.
    
    Specified by:
    
    cloneValue in interface DataValueDescriptor
    
    Parameters:
    
    forceMaterialization - any streams representing the data value will be materialized if true, the data value will be kept as a stream if possible if false
    
    Returns:
    
    A clone of the DataValueDescriptor with the same initial value as this.
    
    See Also:
    
    DataValueDescriptor.cloneValue(boolean)
  - getNewNull
```
public DataValueDescriptor getNewNull()
```
    Description copied from interface: DataValueDescriptor
    
    Get a new null value of the same type as this data value.
    
    Specified by:
    
    getNewNull in interface DataValueDescriptor
    
    See Also:
    
    DataValueDescriptor.getNewNull()
  - getTypeName
```
public java.lang.String getTypeName()
```
    Description copied from interface: DataValueDescriptor
    
    Get the SQL name of the datatype
    
    Specified by:
    
    getTypeName in interface DataValueDescriptor
    
    Returns:
    
    The SQL name of the datatype
    
    See Also:
    
    DataValueDescriptor.getTypeName()
  - typePrecedence
```
public int typePrecedence()
```
    Description copied from class: DataType
    
    Each built-in type in JSQL has a precedence. This precedence determines how to do type promotion when using binary operators. For example, float has a higher precedence than int, so when adding an int to a float, the result type is float. The precedence for some types is arbitrary. For example, it doesn't matter what the precedence of the boolean type is, since it can't be mixed with other types. But the precedence for the number types is critical. The SQL standard requires that exact numeric types be promoted to approximate numeric when one operator uses both. Also, the precedence is arranged so that one will not lose precision when promoting a type.
    
    Specified by:
    
    typePrecedence in interface DataValueDescriptor
    
    Overrides:
    
    typePrecedence in class DataType
    
    Returns:
    
    The precedence of this type.
    
    See Also:
    
    DataValueDescriptor.typePrecedence()
  - getString
```
public java.lang.String getString()
                           throws StandardException
```
    Description copied from interface: DataValueDescriptor
    
    Gets the value in the data value descriptor as a String. Throws an exception if the data value is not a string.
    
    Specified by:
    
    getString in interface DataValueDescriptor
    
    Returns:
    
    The data value as a String.
    
    Throws:
    
    StandardException - Thrown on error
    
    See Also:
    
    DataValueDescriptor.getString()
  - getLength
```
public int getLength()
              throws StandardException
```
    Description copied from interface: DataValueDescriptor
    
    Gets the length of the data value. The meaning of this is implementation-dependent. For string types, it is the number of characters in the string. For numeric types, it is the number of bytes used to store the number. This is the actual length of this value, not the length of the type it was defined as. For example, a VARCHAR value may be shorter than the declared VARCHAR (maximum) length.
    
    Specified by:
    
    getLength in interface DataValueDescriptor
    
    Returns:
    
    The length of the data value
    
    Throws:
    
    StandardException - On error
    
    See Also:
    
    DataValueDescriptor.getLength()
  - estimateMemoryUsage
```
public int estimateMemoryUsage()
```
    Description copied from interface: DataValueDescriptor
    
    Estimate the memory usage in bytes of the data value and the overhead of the class.
    
    Specified by:
    
    estimateMemoryUsage in interface DataValueDescriptor
    
    Returns:
    
    the estimated memory usage
    
    See Also:
    
    DataValueDescriptor.estimateMemoryUsage()
  - readExternalFromArray
```
public void readExternalFromArray(ArrayInputStream in)
                           throws java.io.IOException
```
    Description copied from class: DataType
    
    Read the DataValueDescriptor from the stream. The default implementation calls readExternal(), which accesses the ArrayInputStream as a generic stream. If sub-classes can implement it more efficiently by accessing the array, they should override this method.
    
    Specified by:
    
    readExternalFromArray in interface DataValueDescriptor
    
    Overrides:
    
    readExternalFromArray in class DataType
    
    Parameters:
    
    in - The array stream positioned at the beginning of the byte stream to read from.
    
    Throws:
    
    java.io.IOException - Usual error is if you try to read past limit on the stream.
    
    See Also:
    
    DataValueDescriptor.readExternalFromArray(org.apache.derby.iapi.services.io.ArrayInputStream)
  - setFrom
```
protected void setFrom(DataValueDescriptor theValue)
                throws StandardException
```
    Description copied from class: DataType
    
    Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
    
    Overrides:
    
    setFrom in class DataType
    
    Parameters:
    
    theValue - The DataValueDescriptor that holds the value to which we want to set this DataValueDescriptor's value.
    
    Throws:
    
    StandardException
    
    See Also:
    
    DataType.setFrom(org.apache.derby.iapi.types.DataValueDescriptor)
  - setValueFromResultSet
```
public final void setValueFromResultSet(java.sql.ResultSet resultSet,
                                        int colNumber,
                                        boolean isNullable)
                                 throws java.sql.SQLException
```
    Description copied from interface: DataValueDescriptor
    
    Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
    
    Specified by:
    
    setValueFromResultSet in interface DataValueDescriptor
    
    Parameters:
    
    resultSet - The specified ResultSet.
    
    colNumber - The 1-based column # into the resultSet.
    
    isNullable - Whether or not the column is nullable (No need to call wasNull() if not)
    
    Throws:
    
    java.sql.SQLException - Error accessing the result set
    
    See Also:
    
    DataValueDescriptor.setValueFromResultSet(java.sql.ResultSet, int, boolean)
  - compare
```
public int compare(DataValueDescriptor other)
            throws StandardException
```
    Compare two XML DataValueDescriptors. NOTE: This method should only be used by the database store for the purpose of index positioning--comparisons of XML type are not allowed from the language side of things. That said, all store wants to do is order the NULLs, so we don't actually have to do a full comparison. Just return an order value based on whether or not this XML value and the other XML value are null. As mentioned in the "compare" method of DataValueDescriptor, nulls are considered equal to other nulls and less than all other values. An example of when this method might be used is if the user executed a query like: select i from x_table where x_col is not null
    
    Specified by:
    
    compare in interface DataValueDescriptor
    
    Parameters:
    
    other - The Orderable to compare this one to.
    
    Returns:
    
    <0 - this Orderable is less than other. 0 - this Orderable equals other. >0 - this Orderable is greater than other. The code should not explicitly look for -1, or 1.
    
    Throws:
    
    StandardException - Thrown on error
    
    See Also:
    
    DataValueDescriptor.compare(org.apache.derby.iapi.types.DataValueDescriptor)
  - normalize
```
public void normalize(DataTypeDescriptor desiredType,
                      DataValueDescriptor source)
               throws StandardException
```
    Normalization method - this method will always be called when storing an XML value into an XML column, for example, when inserting/updating. We always force normalization in this case because we need to make sure the qualified type of the value we're trying to store is XML_DOC_ANY--we don't allow anything else.
    
    Specified by:
    
    normalize in interface DataValueDescriptor
    
    Overrides:
    
    normalize in class DataType
    
    Parameters:
    
    desiredType - The type to normalize the source column to
    
    source - The value to normalize
    
    Throws:
    
    StandardException - Thrown if source is not XML_DOC_ANY.
  - getTypeFormatId
```
public int getTypeFormatId()
```
    Description copied from interface: TypedFormat
    
    Get a universally unique identifier for the type of this object.
    
    Specified by:
    
    getTypeFormatId in interface TypedFormat
    
    Returns:
    
    The identifier. (A UUID stuffed in an array of 16 bytes).
    
    See Also:
    
    From the engine's perspective, all XML implementations share the same format id.
  - isNull
```
public boolean isNull()
```
    Description copied from interface: Storable
    
    Return whether the value is null or not.
    
    Specified by:
    
    isNull in interface Storable
    
    Returns:
    
    true if the value is null and false otherwise.
    
    See Also:
    
    Storable.isNull()
  - restoreToNull
```
public void restoreToNull()
```
    Description copied from interface: Storable
    
    Restore this object to its (SQL)null value.
    
    Specified by:
    
    restoreToNull in interface Storable
    
    See Also:
    
    Storable.restoreToNull()
  - readExternal
```
public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException
```
    Read an XML value from an input stream.
    
    Specified by:
    
    readExternal in interface java.io.Externalizable
    
    Parameters:
    
    in - The stream from which we're reading.
    
    Throws:
    
    java.io.IOException
  - writeExternal
```
public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
```
    Write an XML value.
    
    Specified by:
    
    writeExternal in interface java.io.Externalizable
    
    Parameters:
    
    out - The stream to which we're writing.
    
    Throws:
    
    java.io.IOException
  - returnStream
```
public java.io.InputStream returnStream()
```
    Description copied from interface: StreamStorable
    
    Return the on-disk stream state of the object.
    
    Specified by:
    
    returnStream in interface StreamStorable
    
    See Also:
    
    StreamStorable.returnStream()
  - setStream
```
public void setStream(java.io.InputStream newStream)
```
    Description copied from interface: StreamStorable
    
    sets the on-disk stream state for the object.
    
    Specified by:
    
    setStream in interface StreamStorable
    
    See Also:
    
    StreamStorable.setStream(java.io.InputStream)
  - loadStream
```
public void loadStream()
                throws StandardException
```
    Description copied from interface: StreamStorable
    
    Set the value by reading the stream and converting it to an object form.
    
    Specified by:
    
    loadStream in interface StreamStorable
    
    Throws:
    
    StandardException - on error
    
    See Also:
    
    StreamStorable.loadStream()
  - XMLParse
```
public XMLDataValue XMLParse(StringDataValue stringValue,
                             boolean preserveWS,
                             SqlXmlUtil sqlxUtil)
                      throws StandardException
```
    Method to parse an XML string and, if it's valid, store the _serialized_ version locally and then return this XMLDataValue.
    
    Specified by:
    
    XMLParse in interface XMLDataValue
    
    Parameters:
    
    stringValue - The string value to check.
    
    preserveWS - Whether or not to preserve ignorable whitespace.
    
    sqlxUtil - Contains SQL/XML objects and util methods that facilitate execution of XML-related operations
    
    Returns:
    
    If 'text' constitutes a valid XML document, it has been stored in this XML value and this XML value is returned; otherwise, an exception is thrown.
    
    Throws:
    
    StandardException - Thrown on error.
  - XMLSerialize
```
public StringDataValue XMLSerialize(StringDataValue result,
                                    int targetType,
                                    int targetWidth,
                                    int targetCollationType)
                             throws StandardException
```
    The SQL/XML XMLSerialize operator. Serializes this XML value into a string with a user-specified character type, and returns that string via the received StringDataValue (if the received StringDataValue is non-null and of the correct type; else, a new StringDataValue is returned).
    
    Specified by:
    
    XMLSerialize in interface XMLDataValue
    
    Parameters:
    
    result - The result of a previous call to this method, null if not called yet.
    
    targetType - The string type to which we want to serialize.
    
    targetWidth - The width of the target type.
    
    targetCollationType - The collation type of the target type.
    
    Returns:
    
    A serialized (to string) version of this XML object, in the form of a StringDataValue object.
    
    Throws:
    
    StandardException - Thrown on error
  - XMLExists
```
public BooleanDataValue XMLExists(SqlXmlUtil sqlxUtil)
                           throws StandardException
```
    The SQL/XML XMLExists operator. Checks to see if evaluation of the query expression contained within the received util object against this XML value returns at least one item. NOTE: For now, the query expression must be XPath only (XQuery not supported) because that's what Xalan supports.
    
    Specified by:
    
    XMLExists in interface XMLDataValue
    
    Parameters:
    
    sqlxUtil - Contains SQL/XML objects and util methods that facilitate execution of XML-related operations
    
    Returns:
    
    True if evaluation of the query expression stored in sqlxUtil returns at least one node for this XML value; unknown if the xml value is NULL; false otherwise.
    
    Throws:
    
    StandardException - Thrown on error
  - XMLQuery
```
public XMLDataValue XMLQuery(SqlXmlUtil sqlxUtil,
                             XMLDataValue result)
                      throws StandardException
```
    Evaluate the XML query expression contained within the received util object against this XML value and store the results into the received XMLDataValue "result" param (assuming "result" is non-null; else create a new XMLDataValue).
    
    Specified by:
    
    XMLQuery in interface XMLDataValue
    
    Parameters:
    
    sqlxUtil - Contains SQL/XML objects and util methods that facilitate execution of XML-related operations
    
    result - The result of a previous call to this method; null if not called yet.
    
    Returns:
    
    An XMLDataValue whose content corresponds to the serialized version of the results from evaluation of the query expression. Note: this XMLDataValue may not be storable into Derby XML columns.
    
    Throws:
    
    StandardException - thrown on error
  - setXType
```
public void setXType(int xtype)
```
    Set this XML value's qualified type.
    
    Specified by:
    
    setXType in interface XMLDataValue
  - getXType
```
public int getXType()
```
    Retrieve this XML value's qualified type.
    
    Specified by:
    
    getXType in interface XMLDataValue
  - markAsHavingTopLevelAttr
```
public void markAsHavingTopLevelAttr()
```
    Take note of the fact this XML value represents an XML sequence that has one or more top-level attribute nodes.
    
    Specified by:
    
    markAsHavingTopLevelAttr in interface XMLDataValue
  - hasTopLevelAttr
```
public boolean hasTopLevelAttr()
```
    Return whether or not this XML value represents a sequence that has one or more top-level attribute nodes.
    
    Specified by:
    
    hasTopLevelAttr in interface XMLDataValue
  - checkXMLRequirements
```
public static void checkXMLRequirements()
                                 throws StandardException
```
    See if the required JAXP and Xalan classes are in the user's classpath. Assumption is that we will always call this method before instantiating an instance of SqlXmlUtil, and thus we will never get a ClassNotFound exception caused by missing JAXP/Xalan classes. Instead, if either is missing we should throw an informative error indicating what the problem is. NOTE: This method only does the checks necessary to allow successful instantiation of the SqlXmlUtil class. Further checks (esp. the presence of a JAXP _implementation_ in addition to the JAXP _interfaces_) are performed in the SqlXmlUtil constructor.
    
    Throws:
    
    StandardException - thrown if the required classes cannot be located in the classpath.
  - checkJAXPRequirement
```
private static boolean checkJAXPRequirement()
```
    Check if we have a JAXP implementation installed.
    
    Returns:
    
    true if JAXP is installed, or false otherwise
  - checkXPathRequirement
```
private static boolean checkXPathRequirement()
```
    Check if XPath is supported on this platform.
    
    Returns:
    
    true if XPath is supported, or false otherwise

Class XML

Field Summary

Fields inherited from interface org.apache.derby.iapi.types.DataValueDescriptor

Fields inherited from interface org.apache.derby.iapi.types.Orderable

Constructor Summary

Method Summary

Methods inherited from class org.apache.derby.iapi.types.DataType

Methods inherited from interface org.apache.derby.iapi.types.DataValueDescriptor

Methods inherited from class java.lang.Object

Field Detail

UTF8_IMPL_ID

BASE_MEMORY_USAGE

XQ_PASS_BY_REF

XQ_PASS_BY_VALUE

XQ_RETURN_SEQUENCE

XQ_RETURN_CONTENT

XQ_EMPTY_ON_EMPTY

XQ_NULL_ON_EMPTY

XML_DOC_ANY

XML_SEQUENCE

xType

xmlStringValue

xmlReqCheck

containsTopLevelAttr

tmpUtil

Constructor Detail

XML

XML

Method Detail

cloneValue

getNewNull

getTypeName

typePrecedence

getString

getLength

estimateMemoryUsage

readExternalFromArray

setFrom

setValueFromResultSet

compare

normalize

getTypeFormatId

isNull

restoreToNull

readExternal

writeExternal

returnStream

setStream

loadStream

XMLParse

XMLSerialize

XMLExists

XMLQuery

setXType

getXType

markAsHavingTopLevelAttr

hasTopLevelAttr

checkXMLRequirements

checkJAXPRequirement

checkXPathRequirement