org.apache.metamodel.xml

Class XmlDomDataContext

java.lang.Object

org.apache.metamodel.AbstractDataContext

org.apache.metamodel.QueryPostprocessDataContext

org.apache.metamodel.xml.XmlDomDataContext

All Implemented Interfaces:

HasReadTypeConverters, DataContext

public class XmlDomDataContext
extends QueryPostprocessDataContext

A DataContext strategy that reads XML content and maps it to a table-based model similar to the rest of MetaModel. Tables are created by examining the data in the XML file, NOT by reading XML Schemas (xsd/dtd's). This enables compliancy with ALL xml formats but also raises a risk that two XML files with the same format wont nescesarily yield the same table model if some optional attributes or tags are omitted in one of the files. The parsing method applied in this datacontext is DOM based, which means that at upon parsing (only a single point in time), the whole file will be read and it's tree structure kept in memory. Therefore this DataContext is NOT appropriate for large XML files (10's, 100's or 1000's of megabytes).

See Also:

XmlSaxDataContext

Field Summary

Fields

Modifier and Type	Field and Description
static String	NATIVE_TYPE_ATTRIBUTE
static String	NATIVE_TYPE_FOREIGN_KEY
static String	NATIVE_TYPE_PRIMARY_KEY
static String	NATIVE_TYPE_TEXT

Fields inherited from class org.apache.metamodel.QueryPostprocessDataContext

INFORMATION_SCHEMA_NAME, SYSTEM_PROPERTY_CREATE_DEFAULT_TABLE_ALIAS

Constructor Summary

Constructors

Constructor and Description
XmlDomDataContext(File file) Creates an XML DataContext strategy based on a file.
XmlDomDataContext(File file, boolean autoFlattenTables)
XmlDomDataContext(InputSource inputSource, String schemaName, boolean autoFlattenTables)
XmlDomDataContext(Resource resource, boolean autoFlattenTables) Creates an XML DataContext strategy based on a file.
XmlDomDataContext(String schemaName, Document document, boolean autoFlattenTables) Creates an XML DataContext strategy based on an already parsed Document.
XmlDomDataContext(URL url, boolean autoFlattenTables)

Method Summary

Modifier and Type	Method and Description
XmlDomDataContext	autoFlattenTables() Automatically flattens tables that only contain a single data carrying column.
XmlDomDataContext	flattenTables(Relationship relationship)
static Attr[]	getAttributes(Element element)
static Element[]	getChildElements(Element element)
protected Schema	getMainSchema()
protected String	getMainSchemaName()
static String	getTextContent(Element element)
static boolean	hasSiblings(Element element)
boolean	isAutoFlattenTables()
static boolean	isRootElement(Element element)
XmlDomDataContext	loadSchema() Loads the schema if it hasn't been loaded before
DataSet	materializeMainSchemaTable(Table table, List<Column> columnList, int maxRows) Executes a simple one-table query against a table in the main schema of the subclasses of this class.
XmlDomDataContext	reloadSchema() Forces a fresh load of the schema, even though it has already been loaded
void	setAutoFlattenTables(boolean autoFlattenTables)

Methods inherited from class org.apache.metamodel.QueryPostprocessDataContext

addConverter, executeCountQuery, executePrimaryKeyLookupQuery, executeQuery, getDefaultSchemaName, getSchemaByNameInternal, getSchemaNamesInternal, isMainSchemaTable, isScalarFunctionMaterialized, materializeFromItem, materializeMainSchemaTable, materializeMainSchemaTable, materializeMainSchemaTableSelect, materializeTable

Methods inherited from class org.apache.metamodel.AbstractDataContext

compileQuery, executeQuery, executeQuery, getColumnByQualifiedLabel, getDefaultSchema, getSchemaByName, getSchemaNames, getSchemas, getTableByQualifiedLabel, isQualifiedPathDelim, onSchemaCacheRefreshed, parseQuery, query, refreshSchemas

Methods inherited from class java.lang.Object

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

Field Detail

NATIVE_TYPE_PRIMARY_KEY

public static final String NATIVE_TYPE_PRIMARY_KEY

See Also:

Constant Field Values

NATIVE_TYPE_FOREIGN_KEY

public static final String NATIVE_TYPE_FOREIGN_KEY

See Also:

Constant Field Values

NATIVE_TYPE_ATTRIBUTE

public static final String NATIVE_TYPE_ATTRIBUTE

See Also:

Constant Field Values

NATIVE_TYPE_TEXT

public static final String NATIVE_TYPE_TEXT

See Also:

Constant Field Values

Constructor Detail

XmlDomDataContext

public XmlDomDataContext(String schemaName,
                         Document document,
                         boolean autoFlattenTables)

Creates an XML DataContext strategy based on an already parsed Document.

Parameters:

schemaName -

document -

autoFlattenTables -

XmlDomDataContext

public XmlDomDataContext(Resource resource,
                         boolean autoFlattenTables)
                  throws IllegalArgumentException

Creates an XML DataContext strategy based on a file.

Parameters:

resource - the resource to parse

autoFlattenTables - a parameter indicating whether or not tags with only text content or a single attribute should be flattened with it's parent table

Throws:

IllegalArgumentException - if the file does not exist

XmlDomDataContext

public XmlDomDataContext(File file,
                         boolean autoFlattenTables)

XmlDomDataContext

public XmlDomDataContext(InputSource inputSource,
                         String schemaName,
                         boolean autoFlattenTables)

XmlDomDataContext

public XmlDomDataContext(URL url,
                         boolean autoFlattenTables)
                  throws IllegalArgumentException

Throws:

IllegalArgumentException

XmlDomDataContext

public XmlDomDataContext(File file)

Creates an XML DataContext strategy based on a file.

Parameters:

file - the file to parse

Method Detail

isAutoFlattenTables

public boolean isAutoFlattenTables()

setAutoFlattenTables

public void setAutoFlattenTables(boolean autoFlattenTables)

materializeMainSchemaTable

public DataSet materializeMainSchemaTable(Table table,
                                          List<Column> columnList,
                                          int maxRows)

Description copied from class: QueryPostprocessDataContext

Executes a simple one-table query against a table in the main schema of the subclasses of this class.

Specified by:

materializeMainSchemaTable in class QueryPostprocessDataContext

Parameters:

table - the table to query

columnList - the columns of the table to query

maxRows - the maximum amount of rows needed or -1 if all rows are wanted.

Returns:

a dataset with the raw table/column content.

getMainSchemaName

protected String getMainSchemaName()
                            throws MetaModelException

Specified by:

getMainSchemaName in class QueryPostprocessDataContext

Returns:

the name of the main schema that subclasses of this class produce

Throws:

MetaModelException

getMainSchema

protected Schema getMainSchema()
                        throws MetaModelException

Specified by:

getMainSchema in class QueryPostprocessDataContext

Returns:

the main schema that subclasses of this class produce

Throws:

MetaModelException

reloadSchema

public XmlDomDataContext reloadSchema()

Forces a fresh load of the schema, even though it has already been loaded

loadSchema

public XmlDomDataContext loadSchema()

Loads the schema if it hasn't been loaded before

getTextContent

public static String getTextContent(Element element)

getAttributes

public static Attr[] getAttributes(Element element)

hasSiblings

public static boolean hasSiblings(Element element)

getChildElements

public static Element[] getChildElements(Element element)

isRootElement

public static boolean isRootElement(Element element)

flattenTables

public XmlDomDataContext flattenTables(Relationship relationship)

autoFlattenTables

public XmlDomDataContext autoFlattenTables()

Automatically flattens tables that only contain a single data carrying column. Data carrying column are all columns that are not artificial columns (created to enable referential integrity between tag-to-table mapped tables).