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org.apache.xmlbeans
public interface: XmlObject [javadoc | source]

All Implemented Interfaces:
    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:

• Every XML Bean class has an inner Factory class for creating and parsing instances, including XmlObject. Use XmlObject.Factory itself to produce untyped XML trees or XML trees that implement specific subtypes of XmlObject depending on a recognized root document element. If you depend on the automatic type inference, you will want to understand the type inference issues described below.
• To write out an accurate XML file for the XML tree under this XmlObject, use one of the #save methods, or #newInputStream or #newReader . Use #toString to produce a pretty-printed representation of the XML subtree under this XML Object. If you save interior portions of an XML document, you will want to understand the inner contents versus outer container issues described below.
• It is also simple to copy an XmlObject instance to or from a standard DOM tree or SAX stream. Use XmlObject.Factory#parse(Node) , for example, to load from DOM; use XmlObject.Factory#newXmlSaxHandler to load from SAX; use #newDomNode() to save to DOM; and use #save(org.xml.sax.ContentHandler, org.xml.sax.ext.LexicalHandler) to save to SAX.
• Use #validate to validate the subtree of XML under this XML Object. If you wish to get information about the location and reason for validation errors, see XmlOptions#setErrorListener , and use #validate(XmlOptions) .
• Use #newCursor to access the full XML infoset, for example, if you need to determine interleaved element order or manipulate annotations, comments, or mixed content. You can get an element name with a cursor by calling cursor.getName() when the cursor is positioned at an element's START token. See XmlCursor .
• Use #selectPath to find other XmlObjects in the subtree underneath this XmlObject using relative XPaths. (In selectPath, "." indicates the current element or attribute.)

Type inference. When using XmlObject.Factory to parse XML documents, the actual document type is not XmlObject#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:
public static final class	XmlObject.Factory	Static factory class for creating new instances. Note that if a type can be inferred from the XML being loaded (for example, by recognizing the document element QName), then the instance returned by a factory will have the inferred type. Otherwise the Factory will returned an untyped document.

Field Summary
public static final  SchemaType	type	The constant SchemaType object representing this schema type.
static final  int	LESS_THAN	LESS_THAN is -1. See #compareValue .
static final  int	EQUAL	EQUAL is 0. See #compareValue .
static final  int	GREATER_THAN	GREATER_THAN is 1. See #compareValue .
static final  int	NOT_EQUAL	NOT_EQUAL is 2. See #compareValue .

Method from org.apache.xmlbeans.XmlObject Summary:
changeType,   compareTo,   compareValue,   copy,   execQuery,   execQuery,   isImmutable,   isNil,   schemaType,   selectAttribute,   selectAttribute,   selectAttributes,   selectChildren,   selectChildren,   selectChildren,   selectPath,   selectPath,   set,   setNil,   substitute,   toString,   validate,   validate,   valueEquals,   valueHashCode

Method from org.apache.xmlbeans.XmlObject Detail:
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.
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.
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.
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.
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.
public XmlObject[] execQuery(String query, XmlOptions options) Executes a query with options. Use the options parameter to specify the following: To specify this Use this method The document type for the root element. XmlOptions#setDocumentType To replace the document element with the specified QName when constructing the resulting document. XmlOptions#setLoadReplaceDocumentElement 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 Additional namespace mappings to be added when constructing a document. XmlOptions#setLoadAdditionalNamespaces 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
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.
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.
public SchemaType schemaType() The schema type for this instance. This is a permanent, unchanging property of the instance.
public XmlObject selectAttribute(QName attributeName) Selects the content of the attribute with the given name.
public XmlObject selectAttribute(String attributeUri, String attributeLocalName) Selects the content of the attribute with the given name.
public XmlObject[] selectAttributes(QNameSet attributeNameSet) Selects the contents of the attributes that are contained in the elementNameSet.
public XmlObject[] selectChildren(QName elementName) Selects the contents of the children elements with the given name.
public XmlObject[] selectChildren(QNameSet elementNameSet) Selects the contents of the children elements that are contained in the elementNameSet.
public XmlObject[] selectChildren(String elementUri, String elementLocalName) Selects the contents of the children elements with the given name.
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.
public XmlObject[] selectPath(String path, XmlOptions options) Selects a path, applying options.
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.
public void setNil() Sets the value to nil. The element containing the value must be marked as nillable in the schema.
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: the container of this type must be an element a global element with the name newName must exist and must be in the substition group of the containing element the newType type must be consistent with the declared type of the new element 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.
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.
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.
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 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"); } }
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. Note: as of XMLBeans 2.2.1 only implemented for simple type values.
public int valueHashCode()