org.conqat.lib.commons.xml

Class XMLReader<E extends java.lang.Enum<E>,A extends java.lang.Enum<A>,X extends java.lang.Exception>

java.lang.Object

org.conqat.lib.commons.xml.XMLReader<E,A,X>

public abstract class XMLReader<E extends java.lang.Enum<E>,A extends java.lang.Enum<A>,X extends java.lang.Exception>
extends java.lang.Object

Utility class for reading XML documents. The XML document can be validated by an optional schema that is passed via setSchema(URL). Please consult test case XMLReaderTest to see how this class is intended to be used.

Constructor Summary

Constructors

Constructor and Description
XMLReader(java.io.File file, java.nio.charset.Charset encoding, IXMLResolver<E,A> xmlResolver) Create reader.
XMLReader(java.io.File file, IXMLResolver<E,A> xmlResolver) Create new reader.
XMLReader(java.io.Reader reader, IXMLResolver<E,A> xmlResolver) Create reader.
XMLReader(java.lang.String content, IXMLResolver<E,A> xmlResolver) Create reader.

Method Summary

Modifier and Type	Method and Description
protected void	apply(IXMLElementProcessor<E,X>... processors) This works similar to the template mechanism known from XSLT.
protected boolean	getBooleanAttribute(A attribute) Get boolean value of an attribute.
protected java.lang.String	getChildText(E childElement) Get the text content of a child element of the current element.
protected <T extends java.lang.Enum<T>> T	getEnumAttribute(A attribute, java.lang.Class<T> enumClass) Translate attribute value to an enumeration element.
protected <T extends java.lang.Enum<T>> T	getEnumAttributeIgnoreCase(A attribute, java.lang.Class<T> enumClass, T defaultValue) Translate attribute value to an enumeration element.
protected int	getIntAttribute(A attribute) Get int value of an attribute.
protected long	getLongAttribute(A attribute) Get long value of an attribute.
protected java.lang.String	getNonEmptyStringAttribute(A attribute) Get non-empty attribute value.
protected java.lang.String	getStringAttribute(A attribute) Get attribute value.
protected java.lang.String	getText() Get text content of current node.
protected boolean	hasAttribute(A attribute) Returns true if the current element has a given attribute.
protected void	parseFile() Parse file.
protected void	processChildElements(IXMLElementProcessor<E,X> processor) Process the child elements of the current element with a given processor.
protected void	processDecendantElements(IXMLElementProcessor<E,X> processor) Process all descendant elements of the current element with a given processor.
protected void	setSchema(java.net.URL schemaURL) Sets the URL pointing to the schema that is used for validation.

Methods inherited from class java.lang.Object

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

Constructor Detail

XMLReader

public XMLReader(java.io.File file,
                 IXMLResolver<E,A> xmlResolver)
          throws java.io.IOException

Create new reader.

Parameters:

file - the file to be read

xmlResolver - resolvers used by this reader

Throws:

java.io.IOException

XMLReader

public XMLReader(java.io.File file,
                 java.nio.charset.Charset encoding,
                 IXMLResolver<E,A> xmlResolver)
          throws java.io.IOException

Create reader.

Parameters:

file - the file to be read

encoding - XML encoding of the file. No encoding is set if null.

xmlResolver - resolvers used by this reader

Throws:

java.io.IOException

XMLReader

public XMLReader(java.lang.String content,
                 IXMLResolver<E,A> xmlResolver)

Create reader.

Parameters:

content - XML string that gets parsed validation will be performed if null.

xmlResolver - resolvers used by this reader

XMLReader

public XMLReader(java.io.Reader reader,
                 IXMLResolver<E,A> xmlResolver)

Create reader.

Parameters:

reader - the reader used to access the XML document.

xmlResolver - resolvers used by this reader

Method Detail

setSchema

protected void setSchema(java.net.URL schemaURL)

Sets the URL pointing to the schema that is used for validation.

getBooleanAttribute

protected boolean getBooleanAttribute(A attribute)

Get boolean value of an attribute.

Returns:

the boolean value, semantics for non-translatable or empty values is defined by Boolean.parseBoolean(String).

getChildText

protected java.lang.String getChildText(E childElement)

Get the text content of a child element of the current element.

Parameters:

childElement - the child element

Returns:

the text or null if the current element doesn't have the requested child element

getEnumAttribute

protected <T extends java.lang.Enum<T>> T getEnumAttribute(A attribute,
                                                           java.lang.Class<T> enumClass)

Translate attribute value to an enumeration element.

Parameters:

attribute - the attribute

enumClass - the enumeration class

Returns:

the enum value, semantics for non-translatable or empty values is defined by Enum.valueOf(Class, String).

getEnumAttributeIgnoreCase

protected <T extends java.lang.Enum<T>> T getEnumAttributeIgnoreCase(A attribute,
                                                                     java.lang.Class<T> enumClass,
                                                                     T defaultValue)

Translate attribute value to an enumeration element.

Parameters:

attribute - the attribute

enumClass - the enumeration class

defaultValue - the default value to return in case the attribute is not specified or the enumeration does not contain the specified value.

Returns:

The enum value, semantics for non-translatable or empty values is defined by EnumUtils.valueOfIgnoreCase(Class, String).

getIntAttribute

protected int getIntAttribute(A attribute)

Get int value of an attribute.

Returns:

the int value, semantics for non-translatable or empty values is defined by Integer.parseInt(String).

getLongAttribute

protected long getLongAttribute(A attribute)

Get long value of an attribute.

Returns:

the long value, semantics for non-translatable or empty values is defined by Long.parseLong(String).

getStringAttribute

protected java.lang.String getStringAttribute(A attribute)

Get attribute value.

Returns:

the attribute value or the empty string if attribute is undefined.

getNonEmptyStringAttribute

protected java.lang.String getNonEmptyStringAttribute(A attribute)
                                               throws java.io.IOException

Get non-empty attribute value. If the value is null or the empty String, an IOException will be thrown.

Throws:

java.io.IOException

hasAttribute

protected boolean hasAttribute(A attribute)

Returns true if the current element has a given attribute.

getText

protected java.lang.String getText()

Get text content of current node.

parseFile

protected void parseFile()
                  throws org.xml.sax.SAXException,
                         java.io.IOException

Parse file. This sets the current element focus to the document root element. If schema URL was set the document is validated against the schema.

Sub classes should typically wrap this method with a proper error handling mechanism.

Throws:

org.xml.sax.SAXException - if a parsing exceptions occurs

java.io.IOException - if an IO exception occurs.

processChildElements

protected void processChildElements(IXMLElementProcessor<E,X> processor)
                             throws X extends java.lang.Exception

Process the child elements of the current element with a given processor. Target elements are specified by IXMLElementProcessor.getTargetElement().

Parameters:

processor - the processor used to process the elements

Throws:

X - if the processor throws an exception

X extends java.lang.Exception

processDecendantElements

protected void processDecendantElements(IXMLElementProcessor<E,X> processor)
                                 throws X extends java.lang.Exception

Process all descendant elements of the current element with a given processor. In contrast to processChildElements(IXMLElementProcessor), not only direct child elements are processed. Descendant elements are processed in the sequence they are found during a top-down, left-right traversal of the XML document.

Target elements are specified by IXMLElementProcessor.getTargetElement().

Parameters:

processor - the processor used to process the elements

Throws:

X - if the processor throws an exception

X extends java.lang.Exception

apply

protected void apply(IXMLElementProcessor<E,X>... processors)
              throws X extends java.lang.Exception

This works similar to the template mechanism known from XSLT. It traverses the DOM tree starting from the current DOM element in depth-first fashion. For each element it checks if one of the provided processors has the current element as target element. If a matching processor is found, it is executed.

Throws:

java.lang.AssertionError - if multiple processors apply to the same target element

X extends java.lang.Exception