Package com.tangosol.run.xml

Class SimpleElement

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.run.xml.SimpleValue
com.tangosol.run.xml.SimpleElement
All Implemented Interfaces:
ExternalizableLite, PortableObject, XmlElement, XmlSerializable, XmlValue, Serializable, Cloneable
Direct Known Subclasses:
SimpleDocument
public class SimpleElement extends SimpleValue implements XmlElement, XmlSerializable
A simple implementation of the XmlElement interface. Protected methods are provided to support inheriting classes.
Author:
cp 2000.10.20
See Also:

  • Constructor Details

    • SimpleElement

      public SimpleElement()
      Construct an empty SimpleElement. Note: this constructor is needed only to comply with the requirements for the Externalizable and ExternalizableLite interfaces.

    • SimpleElement

      public SimpleElement(String sName)
      Construct a SimpleElement.
      Parameters:
      sName - the name of the element

    • SimpleElement

      public SimpleElement(String sName, Object oValue)
      Construct a SimpleElement.
      Parameters:
      sName - the name of the element
      oValue - an initial value for this element

  • Method Details

    • getName

      public String getName()
      Get the name of the element.
      Specified by:
      getName in interface XmlElement
      Returns:
      the element name

    • setName

      public void setName(String sName)
      Set the Name of the element. This method is intended primarily to be utilized to configure a newly instantiated element before adding it as a child element to another element. Implementations of this interface that support read-only documents are expected to throw UnsupportedOperationException from this method if the document (or this element) is in a read-only state. If this XmlElement has a parent XmlElement, then the implementation of this interface is permitted to throw UnsupportedOperationException from this method. This results from typical document implementations in which the name of an element that is a child of another element is immutable; the W3C DOM interfaces are one example.
      Specified by:
      setName in interface XmlElement
      Parameters:
      sName - the new element name
      Throws:
      IllegalArgumentException - if the name is null or if the name is not a legal XML tag name
      UnsupportedOperationException - if the element cannot be renamed

    • getQualifiedName

      public QualifiedName getQualifiedName()
      Obtains the QualifiedName of the XmlElement.
      Specified by:
      getQualifiedName in interface XmlElement
      Returns:
      the QualifiedName

    • getRoot

      public XmlElement getRoot()
      Get the root element. This is a convenience method. Parent element is retrived using getParent().
      Specified by:
      getRoot in interface XmlElement
      Returns:
      the root element for this element

    • getAbsolutePath

      public String getAbsolutePath()
      Get the '/'-delimited path of the element starting from the root element. This is a convenience method. Elements are retrieved by simple name using getName().
      Specified by:
      getAbsolutePath in interface XmlElement
      Returns:
      the element path

    • getElementList

      public List getElementList()
      Get the list of all child elements. The contents of the list implement the XmlValue interface. If this XmlElement is mutable, then the list returned from this method is expected to be mutable as well. An element should be fully configured before it is added to the list:
      • The List implementation is permitted (and most implementations are expected) to instantiate its own copy of any XmlElement objects added to it.
      • Certain properties of an element (such as Name) may not be settable once the element has been added. (See the comments for the setName method.)
      Specified by:
      getElementList in interface XmlElement
      Returns:
      a List containing all elements of this XmlElement

    • getElement

      public XmlElement getElement(String sName)
      Get a child element. This is a convenience method. Elements are accessed and manipulated via the list returned from getElementList(). If multiple child elements exist that have the specified name, then the behavior of this method is undefined, and it is permitted to return any one of the matching elements, to return null, or to throw an arbitrary runtime exception.
      Specified by:
      getElement in interface XmlElement
      Parameters:
      sName - the specified name
      Returns:
      the specified element as an object implementing XmlElement, or null if the specified child element does not exist

    • getElements

      public Iterator getElements(String sName)
      Get an iterator of child elements that have a specific name. This is a convenience method. Elements are accessed and manipulated via the list returned from getElementList().
      Specified by:
      getElements in interface XmlElement
      Parameters:
      sName - the specified name
      Returns:
      an iterator containing all child elements of the specified name

    • addElement

      public XmlElement addElement(String sName)
      Create a new element and add it as a child element to this element. This is a convenience method. Elements are accessed and manipulated via the list returned from getElementList().
      Specified by:
      addElement in interface XmlElement
      Parameters:
      sName - the name for the new element
      Returns:
      the new XmlElement object
      Throws:
      IllegalArgumentException - if the name is null or if the name is not a legal XML tag name
      UnsupportedOperationException - if this element is immutable or otherwise cannot add a child element

    • findElement

      public XmlElement findElement(String sPath)
      Find a child element with the specified '/'-delimited path. This is based on a subset of the XPath specification, supporting:
      1. Leading '/' to specify root
      2. Use of '/' as a path delimiter
      3. Use of '..' to specify parent
      This is a convenience method. Elements are accessed and manipulated via the list returned from getElementList(). If multiple child elements exist that have the specified name, then the behavior of this method is undefined, and it is permitted to return any one of the matching elements, to return null, or to throw an arbitrary runtime exception.
      Specified by:
      findElement in interface XmlElement
      Parameters:
      sPath - element path
      Returns:
      the specified element as an object implementing XmlElement, or null if the specified child element does not exist

    • getSafeElement

      public XmlElement getSafeElement(String sPath)
      Return the specified child element using the same path notation as supported by findElement, but return a read-only element if the specified element does not exist. This method never returns null. This is a convenience method. Elements are accessed and manipulated via the list returned from getElementList(). If multiple child elements exist that have the specified name, then the behavior of this method is undefined, and it is permitted to return any one of the matching elements, to return null, or to throw an arbitrary runtime exception.
      Specified by:
      getSafeElement in interface XmlElement
      Parameters:
      sPath - element path
      Returns:
      the specified element (never null) as an object implementing XmlElement for read-only use

    • ensureElement

      public XmlElement ensureElement(String sPath)
      Ensure that a child element exists. This is a convenience method. It combines the functionality of findElement() and addElement(). If any part of the path does not exist create new child elements to match the path.
      Specified by:
      ensureElement in interface XmlElement
      Parameters:
      sPath - element path
      Returns:
      the existing or new XmlElement object
      Throws:
      IllegalArgumentException - if the name is null or if any part of the path is not a legal XML tag name
      UnsupportedOperationException - if any element in the path is immutable or otherwise cannot add a child element
      See Also:

    • getAttributeMap

      public Map getAttributeMap()
      Get the map of all attributes. The map is keyed by attribute names. The corresponding values are non-null objects that implement the XmlValue interface.
      Specified by:
      getAttributeMap in interface XmlElement
      Returns:
      a Map containing all attributes of this XmlElement; the return value will never be null, although it may be an empty map

    • getAttribute

      public XmlValue getAttribute(String sName)
      Get an attribute value. This is a convenience method. Attributes are accessed and manipulated via the map returned from getAttributeMap.
      Specified by:
      getAttribute in interface XmlElement
      Parameters:
      sName - the name of the attribute
      Returns:
      the value of the specified attribute, or null if the attribute does not exist or does not have a value

    • setAttribute

      public void setAttribute(String sName, XmlValue val)
      Set an attribute value. If the attribute does not already exist, and the new value is non-null, then the attribute is added and its value is set to the passed value. If the attribute does exist, and the new value is non-null, then the attribute's value is updated to the passed value. If the attribute does exist, but the new value is null, then the attribute and its corresponding value are removed. This is a convenience method. Attributes are accessed and manipulated via the map returned from getAttributeMap.
      Specified by:
      setAttribute in interface XmlElement
      Parameters:
      sName - the name of the attribute
      val - the new value for the attribute; null indicates that the attribute should be removed

    • addAttribute

      public XmlValue addAttribute(String sName)
      Provides a means to add a new attribute value. If the attribute of the same name already exists, it is returned, otherwise a new value is created and added as an attribute. This is a convenience method. Attributes are accessed and manipulated via the map returned from getAttributeMap.
      Specified by:
      addAttribute in interface XmlElement
      Parameters:
      sName - the name of the attribute
      Returns:
      a XmlValue of the same name if it already exists

    • getSafeAttribute

      public XmlValue getSafeAttribute(String sName)
      Get an attribute value, and return a temporary value if the attribute does not exist. This is a convenience method. Attributes are accessed and manipulated via the map returned from getAttributeMap.
      Specified by:
      getSafeAttribute in interface XmlElement
      Parameters:
      sName - the name of the attribute
      Returns:
      the value of the specified attribute, or a temporary value if the attribute does not exist

    • getComment

      public String getComment()
      Get the text of any comments that are in the XML element. An element can contain many comments interspersed randomly with textual values and child elements. In reality, comments are rarely used. The purpose of this method and the corresponding mutator are to ensure that if comments do exist, that their text will be accessible through this interface and not lost through a transfer from one instance of this interface to another.
      Specified by:
      getComment in interface XmlElement
      Returns:
      the comment text from this element (not including the "") or null if there was no comment

    • setComment

      public void setComment(String sComment)
      Set the text of this element's comment. This interface allows a single comment to be associated with the element. The XML specification does not allow a comment to contain the String "--".
      Specified by:
      setComment in interface XmlElement
      Parameters:
      sComment - the comment text
      Throws:
      IllegalArgumentException - if the comment contains "--"

    • writeXml

      public void writeXml(PrintWriter out, boolean fPretty)
      Write the element as it will appear in XML.
      Specified by:
      writeXml in interface XmlElement
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • writeValue

      public void writeValue(PrintWriter out, boolean fPretty)
      Write the value as it will appear in XML.
      Specified by:
      writeValue in interface XmlValue
      Overrides:
      writeValue in class SimpleValue
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • toXml

      public XmlElement toXml()
      Serialize the object into an XmlElement.
      Specified by:
      toXml in interface XmlSerializable
      Returns:
      an XmlElement that contains the serialized form of the object

    • fromXml

      public void fromXml(XmlElement xml)
      Deserialize the object from an XmlElement. This method can throw one of several RuntimeExceptions.
      Specified by:
      fromXml in interface XmlSerializable
      Parameters:
      xml - an XmlElement that contains the serialized form of the object
      Throws:
      UnsupportedOperationException - if this element is immutable

    • readExternal

      public void readExternal(DataInput in) throws IOException
      Restore the contents of this object by loading the object's state from the passed DataInput object.
      Specified by:
      readExternal in interface ExternalizableLite
      Overrides:
      readExternal in class SimpleValue
      Parameters:
      in - the DataInput stream to read data from in order to restore the state of this object
      Throws:
      IOException - if an I/O exception occurs

    • writeExternal

      public void writeExternal(DataOutput out) throws IOException
      Save the contents of this object by storing the object's state into the passed DataOutput object.
      Specified by:
      writeExternal in interface ExternalizableLite
      Overrides:
      writeExternal in class SimpleValue
      Parameters:
      out - the DataOutput stream to write the state of this object to
      Throws:
      IOException - if an I/O exception occurs

    • readExternal

      public void readExternal(PofReader in) throws IOException
      Restore the contents of a user type instance by reading its state using the specified PofReader object.
      Specified by:
      readExternal in interface PortableObject
      Overrides:
      readExternal in class SimpleValue
      Parameters:
      in - the PofReader from which to read the object's state
      Throws:
      IOException - if an I/O error occurs

    • writeExternal

      public void writeExternal(PofWriter out) throws IOException
      Save the contents of a POF user type instance by writing its state using the specified PofWriter object.
      Specified by:
      writeExternal in interface PortableObject
      Overrides:
      writeExternal in class SimpleValue
      Parameters:
      out - the PofWriter to which to write the object's state
      Throws:
      IOException - if an I/O error occurs

    • checkMutable

      protected void checkMutable()
      Validates that the element is mutable, otherwise throws an UnsupportedOperationException.
      Throws:
      UnsupportedOperationException - if the document is immutable

    • isNameMutable

      protected boolean isNameMutable()
      Determine if the name can be changed. The default implementation allows a name to be changed. This can be overridden by inheriting implementations.
      Returns:
      true if the name can be changed

    • instantiateElementList

      protected List instantiateElementList()
      Instantiate a List implementation that will hold child elements.
      Returns:
      a List that supports XmlElements

    • instantiateElement

      protected XmlElement instantiateElement(String sName, Object oValue)
      Instantiate an XmlElement implementation for an element.
      Parameters:
      sName - element name
      oValue - element value
      Returns:
      a new XmlElement to be used as an element

    • instantiateAttributeMap

      protected Map instantiateAttributeMap()
      Instantiate a Map implementation that will support the name to value map used to hold attributes.
      Returns:
      a Map that supports String keys and XmlValue values

    • instantiateAttribute

      protected XmlValue instantiateAttribute()
      Instantiate an XmlValue implementation for an attribute value.
      Returns:
      a new XmlValue to be used as an attribute value

    • writeEmptyTag

      protected void writeEmptyTag(PrintWriter out, boolean fPretty)
      Write the element as a combined start/end tag.
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • writeStartTag

      protected void writeStartTag(PrintWriter out, boolean fPretty)
      Write the element's start tag.
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • writeEndTag

      protected void writeEndTag(PrintWriter out, boolean fPretty)
      Write the element's end tag.
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • writeAttributes

      protected void writeAttributes(PrintWriter out, boolean fPretty)
      Write the attributes as part of a start tag.
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • writeComment

      protected void writeComment(PrintWriter out, boolean fPretty)
      Write the element as it will appear in XML.
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • writeChildren

      protected void writeChildren(PrintWriter out, boolean fPretty)
      Write the element as it will appear in XML.
      Parameters:
      out - a PrintWriter object to use to write to
      fPretty - true to specify that the output is intended to be as human readable as possible

    • toString

      public String toString()
      Format the XML element and all its contained information into a String in a display format. Note that this overrides the contract of the toString method in the super interface XmlValue.
      Specified by:
      toString in interface XmlElement
      Specified by:
      toString in interface XmlValue
      Overrides:
      toString in class SimpleValue
      Returns:
      a String representation of the XML element

    • toString

      public String toString(boolean fPretty)
      Format the XML element and all its contained information into a String in a display format.
      Parameters:
      fPretty - true to specify that the output is intended to be as human readable as possible
      Returns:
      a String representation of the XML element

    • hashCode

      public int hashCode()
      Provide a hash value for this XML element and all of its contained information. Note that this overrides the contract of the hashCode method in the super interface XmlValue. The hash value is defined as a xor of the following:
      1. the hashCode from the element's value (i.e. super.hashCode())
      2. the hashCode from each attribute name
      3. the hashCode from each attribute value
      4. the hashCode from each sub-element
      Specified by:
      hashCode in interface XmlElement
      Specified by:
      hashCode in interface XmlValue
      Overrides:
      hashCode in class SimpleValue
      Returns:
      the hash value for this XML element

    • equals

      public boolean equals(Object o)
      Compare this XML element and all of its contained information with another XML element for equality. Note that this overrides the contract of the equals method in the super interface XmlValue.
      Specified by:
      equals in interface XmlElement
      Specified by:
      equals in interface XmlValue
      Overrides:
      equals in class SimpleValue
      Returns:
      true if the elements are equal, false otherwise

    • clone

      public Object clone()
      Creates and returns a copy of this SimpleElement. The returned copy is a deep clone of this SimpleElement "unlinked" from the parent and mutable
      Specified by:
      clone in interface XmlElement
      Specified by:
      clone in interface XmlValue
      Overrides:
      clone in class SimpleValue
      Returns:
      a clone of this instance.