/*
* InputNode.java July 2006
*
* Copyright (C) 2006, Niall Gallagher <niallg@users.sf.net>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package org.simpleframework.xml.stream;
/**
* The <code>InputNode</code> object represents an iterator for the
* elements within an element. This allows the input node object to
* become a self contained iterator for an element and its children.
* Each child taken from the input node object, is itself an input
* node, and can be used to explore its sub elements without having
* any affect on its outer elements.
*
* @author Niall Gallagher
*/
public interface InputNode extends Node {
/**
* This method is used to determine if this node is the root
* node for the XML document. The root node is the first node
* in the document and has no sibling nodes. This is false
* if the node has a parent node or a sibling node.
*
* @return true if this is the root node within the document
*/
boolean isRoot();
/**
* This is used to determine if this node is an element. This
* allows users of the framework to make a distinction between
* nodes that represent attributes and nodes that represent
* elements. This is particularly useful given that attribute
* nodes do not maintain a node map of attributes.
*
* @return this returns true if the node is an element node
*/
boolean isElement();
/**
* This is used to acquire the namespace prefix for the node.
* If there is no namespace prefix for the node then this will
* return null. Acquiring the prefix enables the qualification
* of the node to be determined. It also allows nodes to be
* grouped by its prefix and allows group operations.
*
* @return this returns the prefix associated with this node
*/
String getPrefix();
/**
* This allows the namespace reference URI to be determined.
* A reference is a globally unique string that allows the
* node to be identified. Typically the reference will be a URI
* but it can be any unique string used to identify the node.
* This allows the node to be identified within the namespace.
*
* @return this returns the associated namespace reference URI
*/
String getReference();
/**
* This provides the position of this node within the document.
* This allows the user of this node to report problems with
* the location within the document, allowing the XML to be
* debugged if it does not match the class schema.
*
* @return this returns the position of the XML read cursor
*/
Position getPosition();
/**
* Provides an attribute from the element represented. If an
* attribute for the specified name does not exist within the
* element represented then this method will return null.
*
* @param name this is the name of the attribute to retrieve
*
* @return this returns the value for the named attribute
*/
InputNode getAttribute(String name);
/**
* This returns a map of the attributes contained within the
* element. If no elements exist within the element then this
* returns an empty map.
*
* @return this returns a map of attributes for the element
*/
NodeMap<InputNode> getAttributes();
/**
* This is used to acquire the <code>Node</code> that is the
* parent of this node. This will return the node that is
* the direct parent of this node and allows for siblings to
* make use of nodes with their parents if required.
*
* @return this returns the parent node for this node
*/
InputNode getParent();
/**
* This is used to return the source object for this node. This
* is used primarily as a means to determine which XML provider
* is parsing the source document and producing the nodes. It
* is useful to be able to determine the XML provider like this.
*
* @return this returns the source of this input node
*/
Object getSource();
/**
* This returns the next child element within this element if
* one exists. If all children have been read, or if there are
* no child elements for this element then this returns null.
*
* @return this returns an input node for the next child
*
* @exception Exception thrown if there was a parse error
*/
InputNode getNext() throws Exception;
/**
* This returns the next child in this element if that child
* has the name provided. If the next child element in this
* node does not have the name given then null is returned.
*
* @param name this is the name of the next child element
*
* @return the next element if it has the name specified
*
* @exception Exception thrown if there was a parse error
*/
InputNode getNext(String name) throws Exception;
/**
* This method is used to skip all child elements from this
* element. This allows elements to be effectively skipped such
* that when parsing a document if an element is not required
* then that element can be completely removed from the XML.
*
* @exception Exception thrown if there was a parse error
*/
void skip() throws Exception;
/**
* This is used to determine if this input node is empty. An
* empty node is one with no attributes or children. This can
* be used to determine if a given node represents an empty
* entity, with which no extra data can be extracted.
*
* @return this returns true if the node is an empty element
*
* @throws Exception thrown if there was a parse error
*/
boolean isEmpty() throws Exception;
}