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org.apache.commons.jxpath.ri.model.beans
Class NullPointer  

java.lang.Object
  org.apache.commons.jxpath.ri.model.NodePointer
      org.apache.commons.jxpath.ri.model.beans.PropertyOwnerPointer
          org.apache.commons.jxpath.ri.model.beans.NullPointer

All Implemented Interfaces:

java.lang.Cloneable, java.lang.Comparable, org.apache.commons.jxpath.Pointer, java.io.Serializable

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public class NullPointer

extends PropertyOwnerPointer

Version:

$Revision: 1.11 $ $Date: 2004/02/29 14:17:41 $

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Field Summary
private  java.lang.String	id
private  org.apache.commons.jxpath.ri.QName	name

 

Fields inherited from class org.apache.commons.jxpath.ri.model.beans.PropertyOwnerPointer

 

Fields inherited from class org.apache.commons.jxpath.ri.model.NodePointer

index, locale, parent, UNKNOWN_NAMESPACE, WHOLE_COLLECTION

 

Constructor Summary

NullPointer(java.util.Locale locale, java.lang.String id)

NullPointer(org.apache.commons.jxpath.ri.model.NodePointer parent, org.apache.commons.jxpath.ri.QName name)           Used for the root node

NullPointer(org.apache.commons.jxpath.ri.QName name, java.util.Locale locale)

 

Method Summary
java.lang.String	asPath()           Returns an XPath that maps to this Pointer.
org.apache.commons.jxpath.ri.model.NodePointer	createChild(org.apache.commons.jxpath.JXPathContext context, org.apache.commons.jxpath.ri.QName name, int index)           Called by a child pointer when it needs to create a parent object for a non-existent collection element.
org.apache.commons.jxpath.ri.model.NodePointer	createChild(org.apache.commons.jxpath.JXPathContext context, org.apache.commons.jxpath.ri.QName name, int index, java.lang.Object value)           Called by a child pointer if that child needs to assign the value supplied in the createPath(context, value) call to a non-existent node.
org.apache.commons.jxpath.ri.model.NodePointer	createPath(org.apache.commons.jxpath.JXPathContext context)           Called by a child pointer when it needs to create a parent object.
org.apache.commons.jxpath.ri.model.NodePointer	createPath(org.apache.commons.jxpath.JXPathContext context, java.lang.Object value)           Called directly by JXPathContext.
boolean	equals(java.lang.Object object)           Determine whether this Object is semantically equal to another Object.
java.lang.Object	getBaseValue()           Returns the value represented by the pointer before indexing.
int	getLength()           If the pointer represents a collection (or collection element), returns the length of the collection.
org.apache.commons.jxpath.ri.QName	getName()           Returns the name of this node.
PropertyPointer	getPropertyPointer()
int	hashCode()           Get a value that represents this Object, as uniquely as possible within the confines of an int.
boolean	isActual()           An actual pointer points to an existing part of an object graph, even if it is null.
boolean	isCollection()           Returns true if the value of the pointer is an array or a Collection.
boolean	isLeaf()           If true, this node does not have children

 

Methods inherited from class org.apache.commons.jxpath.ri.model.beans.PropertyOwnerPointer

attributeIterator, childIterator, compareChildNodePointers, createNodeIterator, getImmediateNode, isDynamicPropertyDeclarationSupported, remove, setIndex, setValue

 

Methods inherited from class org.apache.commons.jxpath.ri.model.NodePointer

clone, compareTo, createAttribute, getDefaultNamespaceURI, getImmediateParentPointer, getImmediateValuePointer, getIndex, getLocale, getNamespaceResolver, getNamespaceURI, getNamespaceURI, getNode, getNodeValue, getParent, getPointerByID, getPointerByKey, getRootNode, getValue, getValuePointer, isAttribute, isContainer, isDefaultNamespace, isLanguage, isNode, isRoot, namespaceIterator, namespacePointer, newChildNodePointer, newNodePointer, printPointerChain, setAttribute, setNamespaceResolver, testNode, toString

 

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

 

Field Detail

name

private org.apache.commons.jxpath.ri.QName name

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id

private java.lang.String id

Constructor Detail

NullPointer

public NullPointer(org.apache.commons.jxpath.ri.QName name,
                   java.util.Locale locale)

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NullPointer

public NullPointer(org.apache.commons.jxpath.ri.model.NodePointer parent,
                   org.apache.commons.jxpath.ri.QName name)

Used for the root node

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NullPointer

public NullPointer(java.util.Locale locale,
                   java.lang.String id)

Method Detail

getName

public org.apache.commons.jxpath.ri.QName getName()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Returns the name of this node. Can be null.

Specified by:

getName in class PropertyOwnerPointer

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getBaseValue

public java.lang.Object getBaseValue()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Returns the value represented by the pointer before indexing. So, if the node represents an element of a collection, this method returns the collection itself.

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isCollection

public boolean isCollection()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Returns true if the value of the pointer is an array or a Collection.

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isLeaf

public boolean isLeaf()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

If true, this node does not have children

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isActual

public boolean isActual()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

An actual pointer points to an existing part of an object graph, even if it is null. A non-actual pointer represents a part that does not exist at all. For instance consider the pointer "/address/street". If both address and street are not null, the pointer is actual. If address is not null, but street is null, the pointer is still actual. If address is null, the pointer is not actual. (In JavaBeans) if address is not a property of the root bean, a Pointer for this path cannot be obtained at all - actual or otherwise.

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getPropertyPointer

public PropertyPointer getPropertyPointer()

Specified by:

getPropertyPointer in class PropertyOwnerPointer

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createPath

public org.apache.commons.jxpath.ri.model.NodePointer createPath(org.apache.commons.jxpath.JXPathContext context,
                                                                 java.lang.Object value)

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Called directly by JXPathContext. Must create path and set value.

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createPath

public org.apache.commons.jxpath.ri.model.NodePointer createPath(org.apache.commons.jxpath.JXPathContext context)

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Called by a child pointer when it needs to create a parent object. Must create an object described by this pointer and return a new pointer that properly describes the new object.

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createChild

public org.apache.commons.jxpath.ri.model.NodePointer createChild(org.apache.commons.jxpath.JXPathContext context,
                                                                  org.apache.commons.jxpath.ri.QName name,
                                                                  int index)

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Called by a child pointer when it needs to create a parent object for a non-existent collection element. It may have to expand the collection, then create an element object and return a new pointer describing the newly created element.

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createChild

public org.apache.commons.jxpath.ri.model.NodePointer createChild(org.apache.commons.jxpath.JXPathContext context,
                                                                  org.apache.commons.jxpath.ri.QName name,
                                                                  int index,
                                                                  java.lang.Object value)

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Called by a child pointer if that child needs to assign the value supplied in the createPath(context, value) call to a non-existent node. This method may have to expand the collection in order to assign the element.

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hashCode

public int hashCode()

Description copied from class: java.lang.Object

Get a value that represents this Object, as uniquely as possible within the confines of an int.

There are some requirements on this method which subclasses must follow:

• Semantic equality implies identical hashcodes. In other words, if a.equals(b) is true, then a.hashCode() == b.hashCode() must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.
• It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.

Notice that since hashCode is used in java.util.Hashtable and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.

The default implementation returns System.identityHashCode(this)

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equals

public boolean equals(java.lang.Object object)

Description copied from class: java.lang.Object

Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

• It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
• It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
• It must be reflexive. a.equals(a) must always be true.
• It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
• a.equals(null) must be false.
• It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a java.lang.ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a java.lang.NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, java.util.IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.

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asPath

public java.lang.String asPath()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

Returns an XPath that maps to this Pointer.

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getLength

public int getLength()

Description copied from class: org.apache.commons.jxpath.ri.model.NodePointer

If the pointer represents a collection (or collection element), returns the length of the collection. Otherwise returns 1 (even if the value is null).

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> commons >> jxpath >> ri >> model >> [ beans overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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