org.apache.xmlbeans
Interface XmlObject

All Superinterfaces:
XmlTokenSource
All Known Subinterfaces:
SimpleValue, XmlAnySimpleType, XmlAnyURI, XmlBase64Binary, XmlBoolean, XmlByte, XmlDate, XmlDateTime, XmlDecimal, XmlDouble, XmlDuration, XmlENTITIES, XmlENTITY, XmlFloat, XmlGDay, XmlGMonth, XmlGMonthDay, XmlGYear, XmlGYearMonth, XmlHexBinary, XmlID, XmlIDREF, XmlIDREFS, XmlInt, XmlInteger, XmlLanguage, XmlLong, XmlName, XmlNCName, XmlNegativeInteger, XmlNMTOKEN, XmlNMTOKENS, XmlNonNegativeInteger, XmlNonPositiveInteger, XmlNormalizedString, XmlNOTATION, XmlPositiveInteger, XmlQName, XmlShort, XmlString, XmlTime, XmlToken, XmlUnsignedByte, XmlUnsignedInt, XmlUnsignedLong, XmlUnsignedShort
All Known Implementing Classes:
FilterXmlObject

public interface XmlObject
extends XmlTokenSource

Corresponds to the XML Schema xs:anyType, the base type for all XML Beans.

Since all XML Schema types are translated into corresponding XML Bean classes, and all Schema type derivation corresponds to Java class inheritance, the fact that all Schema types derive from xs:anyType means that all XML Bean classes derive from XmlObject.

On this base class you will find a number of common facilities that all XML Bean classes provide:

Type inference. When using XmlObject.Factory to parse XML documents, the actual document type is not type itself, but a subtype based on the contents of the parsed document. If the parsed document contains a recognized root document element, then the actual type of the loaded instance will be the matching Document type. For example:

 XmlObject xobj = XmlObject.Factory.parse(myDocument);
 if (xobj instanceof MyOrderDocument) // starts w/ <my-order>
 {
     MyOrderDocument mydoc = (MyOrderDocument)xobj;
     if (!xobj.validate())
         System.out.println("Not a valid my-order document");
 }
 else
 {
     System.out.println("Not a my-order document");
 }
 
Every XML Bean class has its own inner Factory class, so if you actually know exactly which XML Bean document type you want to load as in the example above, you should use the the specific XML Bean Factory class instead. For example:
 MyOrderDocument mydoc = MyOrderDocument.Factory.parse(myDocument);
 
The code above will throw an exception if the parsed document does not begin with the proper (my-order) element.

Inner versus outer. An XmlObject represents the contents of an element or attribute, not the element or attribute itself. So when you validate or save an XmlObject, you are validating or saving its contents, not its container. For example, if the XmlObject represents the contents of an element which happens to itself be in the wrong order relative to its siblings, validate will not complain about the misplacement of the element itself. On the other hand, if elements within the XmlObject are in the wrong order, validate will complain. Similarly, when saving the contents of an interior XmlObject, it is the contents of an element, not the element itself, which is saved by default.

Reading and writing fragments. When reading or writing the contents of a whole XML document, the standard XML reprentation for a document is used. However, there is no standard concrete XML representation for "just the contents" of an interior element or attribute. So when one is needed, the tag <xml-fragment> is used to wrap the contents. This tag is used can also be used to load just the contents for an XmlObject document fragment of arbitrary type. If you wish to save out the XmlObject's container element along with its contents, use XmlOptions.setSaveOuter().

Implementing XmlObject. The XMLBeans library does not support arbitrary implementations of XmlObject - in almost all cases, you should only use the implementations of XmlObject provided by the XMLBeans compiler itself. If you need to implement XmlObject yourself, you should subclass FilterXmlObject in order to delegate to another underlying XmlObject implementation. This technique will allow you to use your code unchanged with future versions of XMLBeans that add additional methods on XmlObject.


Nested Class Summary
static class XmlObject.Factory
          Static factory class for creating new instances.
 
Field Summary
static int EQUAL
          EQUAL is 0.
static int GREATER_THAN
          GREATER_THAN is 1.
static int LESS_THAN
          LESS_THAN is -1.
static int NOT_EQUAL
          NOT_EQUAL is 2.
static SchemaType type
          The constant SchemaType object representing this schema type.
 
Method Summary
 XmlObject changeType(SchemaType newType)
          Changes the schema type associated with this data and returns a new XmlObject instance whose schemaType is the new type.
 int compareTo(Object obj)
          Impelements the Comparable interface by comparing two simple xml values based on their standard XML schema ordering.
 int compareValue(XmlObject obj)
          This comparison method is similar to compareTo, but rather than throwing a ClassCastException when two values are incomparable, it returns the number 2.
 XmlObject copy()
          Returns a deep copy of this XmlObject.
 XmlObject[] execQuery(String query)
          Executes a query.
 XmlObject[] execQuery(String query, XmlOptions options)
          Executes a query with options.
 boolean isImmutable()
          True if the value is an immutable value.
 boolean isNil()
          True if the value is nil.
 SchemaType schemaType()
          The schema type for this instance.
 XmlObject selectAttribute(QName attributeName)
          Selects the content of the attribute with the given name.
 XmlObject selectAttribute(String attributeUri, String attributeLocalName)
          Selects the content of the attribute with the given name.
 XmlObject[] selectAttributes(QNameSet attributeNameSet)
          Selects the contents of the attributes that are contained in the elementNameSet.
 XmlObject[] selectChildren(QName elementName)
          Selects the contents of the children elements with the given name.
 XmlObject[] selectChildren(QNameSet elementNameSet)
          Selects the contents of the children elements that are contained in the elementNameSet.
 XmlObject[] selectChildren(String elementUri, String elementLocalName)
          Selects the contents of the children elements with the given name.
 XmlObject[] selectPath(String path)
          Selects a path.
 XmlObject[] selectPath(String path, XmlOptions options)
          Selects a path, applying options.
 XmlObject set(XmlObject srcObj)
          Set the value/type of this XmlObject to be a copy of the source XmlObject.
 void setNil()
          Sets the value to nil.
 XmlObject substitute(QName newName, SchemaType newType)
          Changes the schema type associated with this data using substitution groups and returns an XmlObject instance whose schemaType is the new type and container name is the new name.
 String toString()
          Returns an XML string for this XML object.
 boolean validate()
          Returns true if the contents of this object are valid accoring to schemaType().
 boolean validate(XmlOptions options)
          Just like validate(), but with options.
 boolean valueEquals(XmlObject obj)
          True if the xml values are equal.
 int valueHashCode()
           
 
Methods inherited from interface org.apache.xmlbeans.XmlTokenSource
documentProperties, dump, getDomNode, monitor, newCursor, newDomNode, newDomNode, newInputStream, newInputStream, newReader, newReader, newXMLInputStream, newXMLInputStream, newXMLStreamReader, newXMLStreamReader, save, save, save, save, save, save, save, save, xmlText, xmlText
 

Field Detail

type

public static final SchemaType type
The constant SchemaType object representing this schema type.


LESS_THAN

public static final int LESS_THAN
LESS_THAN is -1. See compareValue(org.apache.xmlbeans.XmlObject).

See Also:
Constant Field Values

EQUAL

public static final int EQUAL
EQUAL is 0. See compareValue(org.apache.xmlbeans.XmlObject).

See Also:
Constant Field Values

GREATER_THAN

public static final int GREATER_THAN
GREATER_THAN is 1. See compareValue(org.apache.xmlbeans.XmlObject).

See Also:
Constant Field Values

NOT_EQUAL

public static final int NOT_EQUAL
NOT_EQUAL is 2. See compareValue(org.apache.xmlbeans.XmlObject).

See Also:
Constant Field Values
Method Detail

schemaType

public SchemaType schemaType()
The schema type for this instance. This is a permanent, unchanging property of the instance.


validate

public boolean validate()
Returns true if the contents of this object are valid accoring to schemaType().

Does a deep validation of the entire subtree under the object, but does not validate the parents or siblings of the object if the object is in the interior of an xml tree.


validate

public boolean validate(XmlOptions options)

Just like validate(), but with options.

If you wish to collect error messages and locations while validating, use the XmlOptions.setErrorListener(java.util.Collection) method. With that method, you can specify an object in which to store messages related to validation. The following is a simple example.

 // Create an XmlOptions instance and set the error listener.
 XmlOptions validateOptions = new XmlOptions();
 ArrayList errorList = new ArrayList();
 validateOptions.setErrorListener(errorList);
 
 // Validate the XML.
 boolean isValid = newEmp.validate(validateOptions);
 
 // If the XML isn't valid, loop through the listener's contents,
 // printing contained messages.
 if (!isValid)
 {
      for (int i = 0; i < errorList.size(); i++)
      {
          XmlError error = (XmlError)errorList.get(i);
          
          System.out.println("\n");
          System.out.println("Message: " + error.getMessage() + "\n");
          System.out.println("Location of invalid XML: " + 
              error.getCursorLocation().xmlText() + "\n");
      }
 }
 

Parameters:
options - An object that implements the Collection interface.

selectPath

public XmlObject[] selectPath(String path)
Selects a path. Path can be a string or precompiled path String.

The path must be a relative path, where "." represents the element or attribute containg this XmlObject, and it must select only other elements or attributes. If a non-element or non-attribute is selected, an unchecked exception is thrown.

The array that is returned contains all the selected XmlObjects, within the same document, listed in document order. The actual array type of the result is inferred from the closest common base type of selected results.

Here is an example of usage. Suppose we have a global element definition for "owner" whose type is "person":

   <schema targetNamespace="http://openuri.org/sample">
      <element name="owner" type="person"/>
      <complexType name="person">
         [...]
      </complexType>
   </schema>
 
and suppose "owner" tags can be scattered throughout the document. Then we can write the following code to find them all:
 import org.openuri.sample.Person;
 import org.apache.xmlbeans.*;
 [...]
   XmlObject xobj = XmlObject.Factory.parse(myFile);
   Person[] results;
   results = (Person[])xobj.selectPath(
      "declare namespace s='http://www.openuri.org/sample' " +
      ".//s:owner");
 
Notice the way in which namespace declarations are done in XPath 2.0. Since XPath can only navigate within an XML document - it cannot construct new XML - the resulting XmlObjects all reside in the same XML document as this XmlObject itself.


selectPath

public XmlObject[] selectPath(String path,
                              XmlOptions options)
Selects a path, applying options.

See Also:
selectPath(String)

execQuery

public XmlObject[] execQuery(String query)
Executes a query. Query can be a string or precompiled query String.

An XQuery is very similar to an XPath, except that it also permits construction of new XML. As a result, the XmlObjects that are returned from execQuery are in newly created documents, separate from the XmlObject on which the query is executed.

Syntax and usage is otherwise similar to selectPath.

See Also:
selectPath(String)

execQuery

public XmlObject[] execQuery(String query,
                             XmlOptions options)
Executes a query with options. Use the options parameter to specify the following:

To specify thisUse this method
The document type for the root element. XmlOptions.setDocumentType(org.apache.xmlbeans.SchemaType)
To replace the document element with the specified QName when constructing the resulting document. XmlOptions.setLoadReplaceDocumentElement(javax.xml.namespace.QName)
To strip all insignificant whitespace when constructing a document. XmlOptions.setLoadStripWhitespace()
To strip all comments when constructing a document. XmlOptions.setLoadStripComments()
To strip all processing instructions when constructing a document. XmlOptions.setLoadStripProcinsts()
A map of namespace URI substitutions to use when constructing a document. XmlOptions.setLoadSubstituteNamespaces(java.util.Map)
Additional namespace mappings to be added when constructing a document. XmlOptions.setLoadAdditionalNamespaces(java.util.Map)
To trim the underlying XML text buffer immediately after constructing a document, resulting in a smaller memory footprint. XmlOptions.setLoadTrimTextBuffer()
Whether value facets should be checked as they are set. XmlOptions.setValidateOnSet()

Parameters:
query - The XQuery expression.
options - Options as described.
See Also:
execQuery(String)

changeType

public XmlObject changeType(SchemaType newType)
Changes the schema type associated with this data and returns a new XmlObject instance whose schemaType is the new type.

Returns the new XmlObject if the type change was successful, the old XmlObject if no changes could be made.

Certain type changes may be prohibited in the interior of an xml tree due to schema type system constraints (that is, due to a parent container within which the newly specified type is not permissible), but there are no constraints at the roottype changes are never prohibited at the root of an xml tree.

If the type change is allowed, then the new XmlObject should be used rather than the old one. The old XmlObject instance and any other XmlObject instances in the subtree are permanently invalidated and should not be used. (They will return XmlValueDisconnectedException if you try to use them.) If a type change is done on the interior of an Xml tree, then xsi:type attributes are updated as needed.


substitute

public XmlObject substitute(QName newName,
                            SchemaType newType)
Changes the schema type associated with this data using substitution groups and returns an XmlObject instance whose schemaType is the new type and container name is the new name.

Returns the new XmlObject if the substitution was successful, the old XmlObject if no changes could be made.

In order for the operation to succeed, several conditions must hold:

If the type change is allowed, then the new XmlObject should be used rather than the old one. The old XmlObject instance and any other XmlObject instances in the subtree are permanently invalidated and should not be used. (They will return XmlValueDisconnectedException if you try to use them.) If necessary, xsi:type attributes are updated.


isNil

public boolean isNil()
True if the value is nil. Note that in order to be nil, the value must be in an element, and the element containing the value must be marked as nillable in the schema.


setNil

public void setNil()
Sets the value to nil. The element containing the value must be marked as nillable in the schema.


toString

public String toString()
Returns an XML string for this XML object.

The string is pretty-printed. If you want a non-pretty-printed string, or if you want to control options precisely, use the xmlText() methods.

Note that when producing XML any object other than very root of the document, then you are guaranteed to be looking at only a fragment of XML, i.e., just the contents of an element or attribute, and and we will produce a string that starts with an <xml-fragment> tag. The XmlOptions.setSaveOuter() option on xmlText can be used to produce the actual element name above the object if you wish.


isImmutable

public boolean isImmutable()
True if the value is an immutable value. Immutable values do not have a position in a tree; rather, they are stand-alone simple type values. If the object is immutable, the equals() methods tests for value equality, and the object can be used as the key for a hash.


set

public XmlObject set(XmlObject srcObj)
Set the value/type of this XmlObject to be a copy of the source XmlObject. Because the type of the source may be different than this target, this XmlObject may become defunct. In this case the new XmlObject is returned. If no type change happens, the same this will be returned.


copy

public XmlObject copy()
Returns a deep copy of this XmlObject. The returned object has the same type as the current object, and has all the content of the XML document underneath the current object. Note that any parts of the XML document above or outside this XmlObject are not copied.


valueEquals

public boolean valueEquals(XmlObject obj)
True if the xml values are equal. Two different objects (which are distinguished by equals(obj) == false) may of course have equal values (valueEquals(obj) == true).

Usually this method can be treated as an ordinary equvalence relation, but actually it is not is not transitive. Here is a precise specification:

There are two categories of XML object: objects with a known instance type, and objects whose only known type is one of the ur-types (either AnyType or AnySimpleType). The first category is compared in terms of logical value spaces, and the second category is compared lexically.

Within each of these two categories, valueEquals is a well-behaved equivalence relation. However, when comparing an object of known type with an object with ur-type, the comparison is done by attempting to convert the lexical form of the ur-typed object into the other type, and then comparing the results. Ur-typed objects are therefore treated as lexical wildcards and may be equal to objects in different value spaces, even though the objects in different value spaces are not equal to each other.

For example, the anySimpleType value "1" will compare as an equalValue to the string "1", the float value "1.0", the double value "1.0", the decimal "1", and the GYear "1", even though all these objects will compare unequal to each other since they lie in different value spaces.


valueHashCode

public int valueHashCode()

compareTo

public int compareTo(Object obj)
Impelements the Comparable interface by comparing two simple xml values based on their standard XML schema ordering. Throws a ClassCastException if no standard ordering applies, or if the two values are incomparable within a partial order.


compareValue

public int compareValue(XmlObject obj)
This comparison method is similar to compareTo, but rather than throwing a ClassCastException when two values are incomparable, it returns the number 2. The result codes are -1 if this object is less than obj, 1 if this object is greater than obj, zero if the objects are equal, and 2 if the objects are incomparable.


selectChildren

public XmlObject[] selectChildren(QName elementName)
Selects the contents of the children elements with the given name.

Parameters:
elementName - The name of the elements to be selected.
Returns:
Returns the contents of the selected elements.

selectChildren

public XmlObject[] selectChildren(String elementUri,
                                  String elementLocalName)
Selects the contents of the children elements with the given name.

Parameters:
elementUri - The URI of the elements to be selected.
elementLocalName - The local name of the elements to be selected.
Returns:
Returns the contents of the selected elements.

selectChildren

public XmlObject[] selectChildren(QNameSet elementNameSet)
Selects the contents of the children elements that are contained in the elementNameSet.

Parameters:
elementNameSet - Set of element names to be selected.
Returns:
Returns the contents of the selected elements.
See Also:
SchemaType.qnameSetForWildcardElements(), for creating sets of qnames

selectAttribute

public XmlObject selectAttribute(QName attributeName)
Selects the content of the attribute with the given name.

Parameters:
attributeName - The name of the attribute to be selected.
Returns:
Returns the contents of the selected attribute.

selectAttribute

public XmlObject selectAttribute(String attributeUri,
                                 String attributeLocalName)
Selects the content of the attribute with the given name.

Parameters:
attributeUri - The URI of the attribute to be selected.
attributeLocalName - The local name of the attribute to be selected.
Returns:
Returns the content of the selected attribute.

selectAttributes

public XmlObject[] selectAttributes(QNameSet attributeNameSet)
Selects the contents of the attributes that are contained in the elementNameSet.

Parameters:
attributeNameSet - Set of attribute names to be selected.
Returns:
Returns the contents of the selected attributes.
See Also:
SchemaType.qnameSetForWildcardAttributes(), for creating sets of qnames