com.goldencode.p2j.persist.serial

Class XmlImport

java.lang.Object

com.goldencode.p2j.persist.serial.Importer

com.goldencode.p2j.persist.serial.XmlImport

All Implemented Interfaces:

TableReader

public final class XmlImport
extends Importer
implements TableReader

An implementation of the 4GL READ-XML method, which parses an XML stream and reads the content into a temp-table.

Runtime support is partial at this time; not all modes and features are supported. PRODATASET is not supported at this time.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	XmlImport.Relation Internal structure for storing a DataSet relation until the full set of tables is read.

Nested classes/interfaces inherited from class com.goldencode.p2j.persist.serial.Importer

Importer.FieldMaker, Importer.ImportContext

Field Summary

Fields

Modifier and Type	Field and Description
private static java.lang.String	ATTR_NIL Nil attribute name
private java.util.Stack<java.util.Map<java.lang.String,java.lang.String>>	attrs Elements attributes' stack
private int	attrSetOffset The location of the currently processed element.
private java.util.Map<java.lang.String,java.lang.String>	crtAttSet The set of attributes of the current read XML element.
private java.lang.String	dsNsUri The future namespace of the read dataset.
private static java.lang.String	ELEM_IMPORT XSD import element name
private static java.lang.String	ELEM_SCHEMA XSD schema element name
private java.util.Stack<java.lang.String>	elements Elements' stack
private boolean	embeddedSchema Flag indicating that XML document contains embedded schema
private boolean	external Flag indicating that we're reading external schema
private java.util.Map<java.lang.String,java.lang.String>	fieldTypeMapping The desired mapping of fields to new type, if one is defined.
private boolean	inferStructure Flag indicating that the table/dataset structure should be inferred from the XML file.
private boolean	knownTableSchema Flags whether the processed table has a known schema or it should be read from file.
private static CentralLogger	LOG Logger for objects of this type.
private java.lang.String	namespace The future namespace of the read temp-table.
private java.util.Map<java.lang.String,java.lang.String>	prefixByNs XML NS refix for NS by NS
private LookAheadXmlStreamReader	reader The stream where the data is read from.
private java.util.List<XmlImport.Relation>	relations The list of read relations of a dataset being read.
private java.lang.String	schemaLocation 'External' schema location, if one is provided.
private boolean	singleEntry Flag indicating that XML contains row separators.
private java.util.Map<java.lang.String,java.lang.String>	singleEntryAttr Set of attributes and text of the field for single entry syntax.
private java.util.Map<java.lang.String,java.lang.String>	tablesByXmlName The mapping of the legacy table names by their (case-insensitive) XML name.
private static java.lang.String	TEXT_TRUE String constant for 'true'
private boolean	trackXml Flag indicating that XML parsing will be self-checked (for debugging)
private java.lang.String	ttPrefix The future namespace prefix of the read temp-table.
private java.util.Map<java.lang.String,P2JIndex>	uniqueIndexes All unique indexes in this dataset, mapped by their unique names.
private boolean	useLobs Use CLOB/BLOB instead of character/raw type? (Value of override-default-mapping parameter).
private SerializeOptions.Verify	verifySchemaMode Verify schema mode.

Fields inherited from class com.goldencode.p2j.persist.serial.Importer

b4tables, bufMan, childFieldsByChild, ctx, ds, inferredRelations, loader, peerMapping, readingBefore, readMode, savedCtx, source, tables

Constructor Summary

Constructors

Constructor and Description
XmlImport(SourceData source, java.lang.String readMode, java.lang.String schemaLocation, boolean overrideDefaultMapping, java.util.Map<java.lang.String,java.lang.String> fieldTypeMapping, java.lang.String verifySchemaMode) Constructor which configures the importer for an import of a Dataset or a TempTable/Buffer.

Method Summary

Modifier and Type	Method and Description
private void	addField(TempTableBuilder ttb, java.lang.String name, java.lang.Object val, java.util.function.Predicate<java.lang.String> isAttr) Add field to the temp-table.
private void	addValue(java.util.Map<java.lang.String,java.lang.Object> readValues, java.lang.String name, java.lang.String value) Add named value to a map of values, with extent handling.
private boolean	checkNil(TempTableSchema.Column column) Check whether the current temp-table value read from XML content is null.
private java.lang.String	get4GLType(java.lang.String type, java.lang.String proType, java.lang.String nullable, boolean useLobs, java.lang.String tableName, java.lang.String fieldName) Helper method for detecting the 4GL field type using XML data types.
private java.lang.String	getXmlAttribute(java.lang.String fullName) Obtain the value of an attribute for the currently processed XML element.
private java.util.Map<java.lang.String,java.lang.String>	getXmlAttributes() Get map of attributes by name.
private java.util.Map<java.lang.String,java.lang.String>	getXmlNamespaces() Get map of NS prefixes by namespace.
boolean	importDataset(DataSet dataSet, java.util.function.BiConsumer<RecordBuffer,Record> loader) Imports a dataset.
boolean	importDatasetSchema(DataSet ds) Configures a dataset schema or validates it against the XML file.
boolean	importTable(AbstractTempTable tempTable, java.util.function.BiConsumer<RecordBuffer,Record> loader) Reads a TEMP-TABLE from the configured source.
boolean	importTempTableSchema(AbstractTempTable tt) Configures a temp-table schema or validates it against the XML file.
private javax.xml.stream.XMLInputFactory	newXmlInputFactory() Create a factory which treats XML 1.0 files as XML 1.1.
private java.io.Reader	openReader(java.io.InputStream stream) Create a Reader which has the encoding as specified in the XML file targeted by this stream.
private boolean	parseRecord(Buffer parent) Parse XML record to retrieve fields' data, prepare table.
private void	processDsBuffers() Process buffers for the imported dataset tables.
(package private) boolean	processNestedRecord() Process a single nested record.
private void	processRelations(Buffer parent) Pre-process nested relations.
private boolean	readDatasetData() Reads data from XML stream and populates the tables of a DataSet.
private boolean	readDatasetSchema(boolean verify) Reads and processes a DataSet schema.
private boolean	readFromHandle(java.util.function.Function<XmlImport,java.lang.Boolean> reader) Import from a handle.
private boolean	readIndex(java.lang.String indexName, java.lang.String originalName, java.lang.String nsPrefix, boolean primary, boolean unique, boolean word, boolean asIndex) Reads and process an index from the XML stream.
private boolean	readNested(java.lang.String name) Read nested table data.
private boolean	readRecord() Read XML content from the stream corresponding with a single data record and store it in the temp-table.
private boolean	readRecord(Buffer parent) Read XML content from the stream corresponding with a single data record and store it in the temp-table.
private boolean	readRecord2(Buffer parent) Read XML content from the stream corresponding with a single data record and store it in the temp-table.
boolean	readTable(java.lang.String tableName, TempTableBuilder table, java.util.function.BiConsumer<RecordBuffer,Record> loader) Read XML/JSON data from the input source and store it in the just created empty TEMP-TABLE.
private boolean	readTableSchema(AbstractTempTable tempTable, java.lang.String nsPrefix, java.lang.String nsUri) Reads and processes a TEMP-TABLE schema.
private boolean	readTableSchema(java.lang.String tableName, java.lang.String nsPrefix) The read table is automatically added to the dataset if one is processed.
private boolean	readTableSchema(java.lang.String xmlNodeName, java.lang.String nsPrefix, java.lang.String nsUri) Reads and processes an AbstractTempTable schema.
private java.lang.String	readText() Read text content from within an element or a CDATA section.
private java.lang.String	removeNsPrefix(java.lang.String qname) Remove the namespace prefix from the qualified name
private boolean	skipRecord(java.lang.String tableName) Skip the whole subtree because the record belongs to an unknown table.
protected ParmType	typeOf(java.lang.Object val) Get an inferred type of the value.

Methods inherited from class com.goldencode.p2j.persist.serial.Importer

fillFromParent, getColumn, peekContext, persist, popContext, populateRecord, processHiddenFk, processId, processRowState, pushContext, setField, setField, setField, setParentValues, setupDataset

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final CentralLogger LOG

Logger for objects of this type.

ELEM_SCHEMA

private static final java.lang.String ELEM_SCHEMA

XSD schema element name

See Also:

Constant Field Values

ELEM_IMPORT

private static final java.lang.String ELEM_IMPORT

XSD import element name

See Also:

Constant Field Values

ATTR_NIL

private static final java.lang.String ATTR_NIL

Nil attribute name

See Also:

Constant Field Values

TEXT_TRUE

private static final java.lang.String TEXT_TRUE

String constant for 'true'

See Also:

Constant Field Values

verifySchemaMode

private final SerializeOptions.Verify verifySchemaMode

Verify schema mode.

useLobs

private final boolean useLobs

Use CLOB/BLOB instead of character/raw type? (Value of override-default-mapping parameter).

dsNsUri

private java.lang.String dsNsUri

The future namespace of the read dataset.

namespace

private java.lang.String namespace

The future namespace of the read temp-table.

ttPrefix

private java.lang.String ttPrefix

The future namespace prefix of the read temp-table.

fieldTypeMapping

private final java.util.Map<java.lang.String,java.lang.String> fieldTypeMapping

The desired mapping of fields to new type, if one is defined.

schemaLocation

private final java.lang.String schemaLocation

'External' schema location, if one is provided.

external

private boolean external

Flag indicating that we're reading external schema

tablesByXmlName

private final java.util.Map<java.lang.String,java.lang.String> tablesByXmlName

The mapping of the legacy table names by their (case-insensitive) XML name.

embeddedSchema

private boolean embeddedSchema

Flag indicating that XML document contains embedded schema

relations

private java.util.List<XmlImport.Relation> relations

The list of read relations of a dataset being read.

prefixByNs

private java.util.Map<java.lang.String,java.lang.String> prefixByNs

XML NS refix for NS by NS

uniqueIndexes

private final java.util.Map<java.lang.String,P2JIndex> uniqueIndexes

All unique indexes in this dataset, mapped by their unique names.

reader

private LookAheadXmlStreamReader reader

The stream where the data is read from.

crtAttSet

private java.util.Map<java.lang.String,java.lang.String> crtAttSet

The set of attributes of the current read XML element. Do NOT access it directly, instead use the getXmlAttribute() method.

attrSetOffset

private int attrSetOffset

The location of the currently processed element. Used to check validation of the crtAttSet, which acts as a cache. If the position of the current XML element is different from attrSetOffset then crtAttSet needs to be updated.

knownTableSchema

private boolean knownTableSchema

Flags whether the processed table has a known schema or it should be read from file. This is irrelevant when processing DataSets.

inferStructure

private boolean inferStructure

Flag indicating that the table/dataset structure should be inferred from the XML file.

trackXml

private boolean trackXml

Flag indicating that XML parsing will be self-checked (for debugging)

elements

private java.util.Stack<java.lang.String> elements

Elements' stack

attrs

private java.util.Stack<java.util.Map<java.lang.String,java.lang.String>> attrs

Elements attributes' stack

singleEntryAttr

private java.util.Map<java.lang.String,java.lang.String> singleEntryAttr

Set of attributes and text of the field for single entry syntax.

singleEntry

private boolean singleEntry

Flag indicating that XML contains row separators.

Constructor Detail

XmlImport

public XmlImport(SourceData source,
                 java.lang.String readMode,
                 java.lang.String schemaLocation,
                 boolean overrideDefaultMapping,
                 java.util.Map<java.lang.String,java.lang.String> fieldTypeMapping,
                 java.lang.String verifySchemaMode)

Constructor which configures the importer for an import of a Dataset or a TempTable/Buffer.

Parameters:

source - XML data source which normalizes access of various media to an input stream.

readMode - Read mode to determine how records are stored and how non-unique records are handled. Not currently honored, except temp-table records are deleted if mode is EMPTY.

schemaLocation - Path to XML schema (not currently used).

overrideDefaultMapping - Not currently used.

fieldTypeMapping - Not currently used.

verifySchemaMode - Not currently used.

Method Detail

importDatasetSchema

public boolean importDatasetSchema(DataSet ds)

Configures a dataset schema or validates it against the XML file. The other parameters are set in constructor.

Parameters:

ds - The destination for read schema.

Returns:

true on success. On failure, false is returned and the eventual error is already displayed.

importTempTableSchema

public boolean importTempTableSchema(AbstractTempTable tt)

Configures a temp-table schema or validates it against the XML file. The other parameters are set in the constructor.

Parameters:

tt - The destination for read schema.

Returns:

true on success. On failure, false is returned and the eventual error is already displayed.

importDataset

public boolean importDataset(DataSet dataSet,
                             java.util.function.BiConsumer<RecordBuffer,Record> loader)

Imports a dataset. The other parameters are set in constructor.

Parameters:

dataSet - The destination for read data.

loader - A BiConsumer which helps loading a Record into the buffer.

Returns:

true on success. On failure, false is returned and the eventual error is already displayed.

importTable

public boolean importTable(AbstractTempTable tempTable,
                           java.util.function.BiConsumer<RecordBuffer,Record> loader)

Reads a TEMP-TABLE from the configured source.

Parameters:

tempTable - Temp-table in which data will be stored.

loader - A BiConsumer which helps loading a Record into the buffer.

Returns:

true on success.

readTable

public boolean readTable(java.lang.String tableName,
                         TempTableBuilder table,
                         java.util.function.BiConsumer<RecordBuffer,Record> loader)
                  throws PersistenceException

Read XML/JSON data from the input source and store it in the just created empty TEMP-TABLE.

Specified by:

readTable in interface TableReader

Parameters:

tableName - table name

table - TEMP-TABLE to be loaded.

loader - A BiConsumer which helps loading a Record into the buffer.

Returns:

true on success.

Throws:

PersistenceException - if there is any error reading or storing XML/JSON data.

typeOf

protected ParmType typeOf(java.lang.Object val)
                   throws PersistenceException

Get an inferred type of the value.

Specified by:

typeOf in class Importer

Parameters:

val - value to be analyzed

Returns:

an inferred type of the value.

Throws:

PersistenceException - on invalid value type

readFromHandle

private boolean readFromHandle(java.util.function.Function<XmlImport,java.lang.Boolean> reader)

Import from a handle. Only X-Document is currently supported.

Parameters:

reader - The reader function.

Returns:

true if the import was successful.

openReader

private java.io.Reader openReader(java.io.InputStream stream)
                           throws java.io.IOException

Create a Reader which has the encoding as specified in the XML file targeted by this stream.

If no encoding is specified, it defaults to UTF-8.

The reader is wrapped in a filter which automatically escapes ISO control characters which are not whitespace.

Parameters:

stream - input stream.

Returns:

A reader for this stream with the proper encoding.

Throws:

java.io.IOException

newXmlInputFactory

private javax.xml.stream.XMLInputFactory newXmlInputFactory()

Create a factory which treats XML 1.0 files as XML 1.1.

Returns:

A factory to read XML 1.0 files as XML 1.1, to allow control characters.

readTableSchema

private boolean readTableSchema(AbstractTempTable tempTable,
                                java.lang.String nsPrefix,
                                java.lang.String nsUri)
                         throws javax.xml.stream.XMLStreamException

Reads and processes a TEMP-TABLE schema.

Parameters:

nsPrefix - The detected XML namespace prefix.

nsUri - The detected XML namespace URI.

Returns:

true on success and false otherwise. When false is returned then the error message has already been dispatched to ErrorManager.

Throws:

javax.xml.stream.XMLStreamException - If a XML-related error occurs (like an unexpected end of stream).

readDatasetSchema

private boolean readDatasetSchema(boolean verify)
                           throws javax.xml.stream.XMLStreamException

Reads and processes a DataSet schema. If the DataSet is in CLEAR state, the structure is initialized and its tables and relations are set up. Otherwise the schema is checked according to verifySchemaMode.

Parameters:

verify - When true the schema is only verified. Otherwise the methods attempts to create the read schema into the dataset.

Returns:

true on success and false otherwise. When false is returned then the error message has already been dispatched to ErrorManager.

Throws:

javax.xml.stream.XMLStreamException - If a XML-related error occurs (like an unexpected end of stream).

removeNsPrefix

private java.lang.String removeNsPrefix(java.lang.String qname)

Remove the namespace prefix from the qualified name

Parameters:

qname - qualified name to be simplified

Returns:

name w/o prefix

processDsBuffers

private void processDsBuffers()

Process buffers for the imported dataset tables.

readTableSchema

private boolean readTableSchema(java.lang.String xmlNodeName,
                                java.lang.String nsPrefix,
                                java.lang.String nsUri)
                         throws javax.xml.stream.XMLStreamException

Reads and processes an AbstractTempTable schema. If the TempTable is in CLEAR state, the structure is initialized. Otherwise the schema is checked according to verifySchemaMode.

Parameters:

xmlNodeName - The detected XML node name.

nsPrefix - The detected XML namespace prefix.

nsUri - The detected XML namespace URI.

Returns:

true on success and false otherwise. When false is returned then the error message has already been dispatched to ErrorManager.

Throws:

javax.xml.stream.XMLStreamException - If a XML-related error occurs (like an unexpected end of stream).

readIndex

private boolean readIndex(java.lang.String indexName,
                          java.lang.String originalName,
                          java.lang.String nsPrefix,
                          boolean primary,
                          boolean unique,
                          boolean word,
                          boolean asIndex)
                   throws javax.xml.stream.XMLStreamException

Reads and process an index from the XML stream.

Parameters:

indexName - The index name (aka XML name).

originalName - The index's original name only if the xml name was altered because of collisions.

nsPrefix - The detected XML namespace prefix.

primary - true if this is a primary index.

unique - true is this is an unique index.

word - true is this is a word index.

asIndex - true is this taken from the 'index' node.

Returns:

true on success and false otherwise. When false is returned then the error message has already been dispatched to ErrorManager.

Throws:

javax.xml.stream.XMLStreamException - If a XML-related error occurs (like an unexpected end of stream).

readDatasetData

private boolean readDatasetData()
                         throws javax.xml.stream.XMLStreamException,
                                PersistenceException

Reads data from XML stream and populates the tables of a DataSet.

Returns:

true on success and false otherwise. When false is returned then the error message has already been dispatched to ErrorManager.

Throws:

javax.xml.stream.XMLStreamException - if a XML-related error occurs (like an unexpected end of stream).

PersistenceException - if a persistence error occurs while saving data to database.

readTableSchema

private boolean readTableSchema(java.lang.String tableName,
                                java.lang.String nsPrefix)
                         throws javax.xml.stream.XMLStreamException

The read table is automatically added to the dataset if one is processed. Note that the <xsd:element> node for this table was already processed (no look-ahead) in order to decide to call this method.

Parameters:

tableName - The name of the table which is being processed.

nsPrefix - The detected XML namespace prefix.

Returns:

true if the operation is successful. If the operation fails, false is returned.

Throws:

javax.xml.stream.XMLStreamException - in the event of an exception occurred while reading the XML stream.

skipRecord

private boolean skipRecord(java.lang.String tableName)
                    throws javax.xml.stream.XMLStreamException

Skip the whole subtree because the record belongs to an unknown table. Fast forward to the end tag of the record.

Parameters:

tableName - The table name.

Returns:

true on success. Otherwise an error is issued before returning false.

Throws:

javax.xml.stream.XMLStreamException - if the XML stream cannot be parsed.

readRecord

private boolean readRecord()
                    throws javax.xml.stream.XMLStreamException,
                           PersistenceException

Read XML content from the stream corresponding with a single data record and store it in the temp-table.

This version ensures that the group and decimal separators are ',' and '.' for the duration of the deserialization.

Throws:

javax.xml.stream.XMLStreamException - if there is an error reading XML content from the stream.

PersistenceException - if there is an error storing data in the temp-table.

readRecord

private boolean readRecord(Buffer parent)
                    throws javax.xml.stream.XMLStreamException,
                           PersistenceException

Read XML content from the stream corresponding with a single data record and store it in the temp-table.

This version ensures that the group and decimal separators are ',' and '.' for the duration of the deserialization.

Parameters:

parent - The parent buffer, if this is called for a NESTED relation fields.

Throws:

javax.xml.stream.XMLStreamException - if there is an error reading XML content from the stream.

PersistenceException - if there is an error storing data in the temp-table.

readRecord2

private boolean readRecord2(Buffer parent)
                     throws javax.xml.stream.XMLStreamException,
                            PersistenceException

Read XML content from the stream corresponding with a single data record and store it in the temp-table.

Parameters:

parent - The parent buffer, if this is called for a NESTED relation fields.

Throws:

javax.xml.stream.XMLStreamException - if there is an error reading XML content from the stream.

PersistenceException - if there is an error storing data in the temp-table.

processNestedRecord

boolean processNestedRecord()
                     throws javax.xml.stream.XMLStreamException,
                            PersistenceException

Process a single nested record. It may have other nested records as well.

Returns:

true on success.

Throws:

javax.xml.stream.XMLStreamException

PersistenceException

processRelations

private void processRelations(Buffer parent)

Pre-process nested relations.

Parameters:

parent - The parent buffer, if this is called for a NESTED relation fields.

parseRecord

private boolean parseRecord(Buffer parent)
                     throws javax.xml.stream.XMLStreamException,
                            PersistenceException

Parse XML record to retrieve fields' data, prepare table. populate the first record, and store it in the temp-table.

Parameters:

parent - The parent buffer, if this is called for a NESTED relation fields.

Throws:

javax.xml.stream.XMLStreamException - if there is an error reading XML content from the stream.

PersistenceException - if there is an error storing data in the temp-table.

readNested

private boolean readNested(java.lang.String name)
                    throws PersistenceException

Read nested table data.

Parameters:

name - The name of the table to be populated.

Returns:

true in success

Throws:

PersistenceException - in error

addValue

private void addValue(java.util.Map<java.lang.String,java.lang.Object> readValues,
                      java.lang.String name,
                      java.lang.String value)

Add named value to a map of values, with extent handling.

Parameters:

readValues - The map which colelcts the key/values pairs.

name - The key.

value - The value associated with the key. If there is already a scalar value associated with the key, it is replaced by a list containing the extent data. If the old value is already a list the value is appended to it.

readText

private java.lang.String readText()
                           throws javax.xml.stream.XMLStreamException

Read text content from within an element or a CDATA section.

Returns:

Text which was read.

Throws:

javax.xml.stream.XMLStreamException - if there is an error reading XML content from the stream.

checkNil

private boolean checkNil(TempTableSchema.Column column)

Check whether the current temp-table value read from XML content is null. If so, check whether the associated column allows null values.

Parameters:

column - Schema information for the associated column.

Returns:

true if the XML content is nil; else false.

Throws:

ErrorConditionException - if value is nil and column does not allow null values.

getXmlAttribute

private java.lang.String getXmlAttribute(java.lang.String fullName)

Obtain the value of an attribute for the currently processed XML element. The method uses a cache map in order not to process the attributes multiple times. Once they are collected, the attribute values are kept until a request for other element is issued. The method uses attrSetOffset to compare the location of the current element. If they are different, the cache is updated. Note that the cache is updated only on request, the current of crtAttSet may be stalled if the getXmlAttribute() was not yet called for the new element.

Parameters:

fullName - The full-name of the attribute.

Returns:

The value of the attribute if found and null if there is no such attribute in current element.

getXmlAttributes

private java.util.Map<java.lang.String,java.lang.String> getXmlAttributes()

Get map of attributes by name.

Returns:

the map of attributes by name.

getXmlNamespaces

private java.util.Map<java.lang.String,java.lang.String> getXmlNamespaces()

Get map of NS prefixes by namespace.

Returns:

the map of NS prefixes by namespace.

get4GLType

private java.lang.String get4GLType(java.lang.String type,
                                    java.lang.String proType,
                                    java.lang.String nullable,
                                    boolean useLobs,
                                    java.lang.String tableName,
                                    java.lang.String fieldName)

Helper method for detecting the 4GL field type using XML data types. Since some of them overlap, the additional parameters are used to distinct between them.

Parameters:

type - The pure xsd type.

proType - Additional information needed to distinct the original 4GL type.

nullable - Whether the original field type was nullable.

useLobs - If true, clob and blob types will be used instead of character and raw, respectively.

tableName - Optional. If specified the table name is looked up in the type map instead of the type specified in XML file.

fieldName - Optional. If specified the field name is looked up in the type map instead of the type specified in XML file.

Returns:

The original 4GL type of the field. If one cannot be detected using the provided data, null is returned.

See Also:

Util.xsdMap, Util.xsdProdataMap

addField

private void addField(TempTableBuilder ttb,
                      java.lang.String name,
                      java.lang.Object val,
                      java.util.function.Predicate<java.lang.String> isAttr)
               throws PersistenceException

Add field to the temp-table.

Parameters:

ttb - The destination temp-table builder.

name - The name of the field to be added.

val - The value of field. It is used for inferring the type of the new field.

isAttr - A predicate which allows identification of fields with ATTRIBUTE node type.

Throws:

PersistenceException - If the type of the field cannot be inferred from the provided value.