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/*
* OutputElement.java July 2006
*
* Copyright (C) 2006, Niall Gallagher
*
* 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 OutputElement object represents an XML element.
* Attributes can be added to this before ant child element has been
* acquired from it. Once a child element has been acquired the
* attributes will be written an can no longer be manipulated, the
* same applies to any text value set for the element.
*
* @author Niall Gallagher
*/
class OutputElement implements OutputNode {
/**
* Represents the attributes that have been set for the element.
*/
private OutputNodeMap table;
/**
* This is the namespace map that contains the namespaces.
*/
private NamespaceMap scope;
/**
* Used to write the start tag and attributes for the document.
*/
private NodeWriter writer;
/**
* This is the parent XML element to this output node.
*/
private OutputNode parent;
/**
* This is the namespace reference URI associated with this.
*/
private String reference;
/**
* This is the comment that has been set on this element.
*/
private String comment;
/**
* Represents the value that has been set for the element.
*/
private String value;
/**
* Represents the name of the element for this output node.
*/
private String name;
/**
* This is the output mode that this element object is using.
*/
private Mode mode;
/**
* Constructor for the OutputElement object. This is
* used to create an output element that can create elements for
* an XML document. This requires the writer that is used to
* generate the actual document and the name of this node.
*
* @param parent this is the parent node to this output node
* @param writer this is the writer used to generate the file
* @param name this is the name of the element this represents
*/
public OutputElement(OutputNode parent, NodeWriter writer, String name) {
this.scope = new PrefixResolver(parent);
this.table = new OutputNodeMap(this);
this.mode = Mode.INHERIT;
this.writer = writer;
this.parent = parent;
this.name = name;
}
/**
* This is used to acquire the prefix for this output node. This
* will search its parent nodes until the prefix that is currently
* in scope is found. If a prefix is not found in the parent
* nodes then a prefix in the current nodes namespace mappings is
* searched, failing that the prefix returned is null.
*
* @return this returns the prefix associated with this node
*/
public String getPrefix() {
return getPrefix(true);
}
/**
* This is used to acquire the prefix for this output node. If
* the output node is an element then this will search its parent
* nodes until the prefix that is currently in scope is found.
* If however this node is an attribute then the hierarchy of
* nodes is not searched as attributes to not inherit namespaces.
*
* @param inherit if there is no explicit prefix then inherit
*
* @return this returns the prefix associated with this node
*/
public String getPrefix(boolean inherit) {
String prefix = scope.getPrefix(reference);
if(inherit) {
if(prefix == null) {
return parent.getPrefix();
}
}
return prefix;
}
/**
* This is used to acquire the namespace URI reference associated
* with this node. Although it is recommended that the namespace
* reference is a URI it does not have to be, it can be any unique
* identifier that can be used to distinguish the qualified names.
*
* @return this returns the namespace URI reference for this
*/
public String getReference() {
return reference;
}
/**
* This is used to set the reference for the node. Setting the
* reference implies that the node is a qualified node within the
* XML document. Both elements and attributes can be qualified.
* Depending on the prefix set on this node or, failing that, any
* parent node for the reference, the element will appear in the
* XML document with that string prefixed to the node name.
*
* @param reference this is used to set the reference for the node
*/
public void setReference(String reference) {
this.reference = reference;
}
/**
* This returns the NamespaceMap for this node. Only
* an element can have namespaces, so if this node represents an
* attribute the elements namespaces will be provided when this is
* requested. By adding a namespace it becomes in scope for the
* current element all all child elements of that element.
*
* @return this returns the namespaces associated with the node
*/
public NamespaceMap getNamespaces() {
return scope;
}
/**
* This is used to acquire the Node 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
*/
public OutputNode getParent() {
return parent;
}
/**
* Returns the name of the node that this represents. This is
* an immutable property and cannot be changed. This will be
* written as the tag name when this has been committed.
*
* @return returns the name of the node that this represents
*/
public String getName() {
return name;
}
/**
* Returns the value for the node that this represents. This
* is a modifiable property for the node and can be changed,
* however once committed any change will be irrelevant.
*
* @return the name of the value for this node instance
*/
public String getValue() {
return value;
}
/**
* This is used to get the text comment for the element. This can
* be null if no comment has been set. If no comment is set on
* the node then no comment will be written to the resulting XML.
*
* @return this is the comment associated with this element
*/
public String getComment() {
return comment;
}
/**
* 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
*/
public boolean isRoot() {
return writer.isRoot(this);
}
/**
* The Mode is used to indicate the output mode
* of this node. Three modes are possible, each determines
* how a value, if specified, is written to the resulting XML
* document. This is determined by the setData
* method which will set the output to be CDATA or escaped,
* if neither is specified the mode is inherited.
*
* @return this returns the mode of this output node object
*/
public Mode getMode() {
return mode;
}
/**
* This is used to set the output mode of this node to either
* be CDATA, escaped, or inherited. If the mode is set to data
* then any value specified will be written in a CDATA block,
* if this is set to escaped values are escaped. If however
* this method is set to inherited then the mode is inherited
* from the parent node.
*
* @param mode this is the output mode to set the node to
*/
public void setMode(Mode mode) {
this.mode = mode;
}
/**
* This returns a NodeMap which can be used to add
* nodes to the element before that element has been committed.
* Nodes can be removed or added to the map and will appear as
* attributes on the written element when it is committed.
*
* @return returns the node map used to manipulate attributes
*/
public OutputNodeMap getAttributes() {
return table;
}
/**
* This is used to set a text comment to the element. This will
* be written just before the actual element is written. Only a
* single comment can be set for each output node written.
*
* @param comment this is the comment to set on the node
*/
public void setComment(String comment) {
this.comment = comment;
}
/**
* This is used to set a text value to the element. This should
* be added to the element if the element contains no child
* elements. If the value cannot be added an exception is thrown.
*
* @param value this is the text value to add to this element
*/
public void setValue(String value) {
this.value = value;
}
/**
* This is used to change the name of an output node. This will
* only affect the name of the node if the node has not yet been
* committed. If the node is committed then this will not be
* reflected in the resulting XML generated.
*
* @param name this is the name to change the node to
*/
public void setName(String name) {
this.name = name;
}
/**
* This is used to set the output mode of this node to either
* be CDATA or escaped. If this is set to true the any value
* specified will be written in a CDATA block, if this is set
* to false the values is escaped. If however this method is
* never invoked then the mode is inherited from the parent.
*
* @param data if true the value is written as a CDATA block
*/
public void setData(boolean data) {
if(data) {
mode = Mode.DATA;
} else {
mode = Mode.ESCAPE;
}
}
/**
* This method is used for convinience to add an attribute node
* to the attribute NodeMap. The attribute added
* can be removed from the element by useing the node map.
*
* @param name this is the name of the attribute to be added
* @param value this is the value of the node to be added
*
* @return this will return the attribute that was just set
*/
public OutputNode setAttribute(String name, String value) {
return table.put(name, value);
}
/**
* This is used to create a child element within the element that
* this object represents. When a new child is created with this
* method then the previous child is committed to the document.
* The created OutputNode object can be used to add
* attributes to the child element as well as other elements.
*
* @param name this is the name of the child element to create
*/
public OutputNode getChild(String name) throws Exception {
return writer.writeElement(this, name);
}
/**
* This is used to remove any uncommitted changes. Removal of an
* output node can only be done if it has no siblings and has
* not yet been committed. If the node is committed then this
* will throw an exception to indicate that it cannot be removed.
*
* @throws Exception thrown if the node cannot be removed
*/
public void remove() throws Exception {
writer.remove(this);
}
/**
* This will commit this element and any uncommitted elements
* elements that are decendents of this node. For instance if
* any child or grand child remains open under this element
* then those elements will be closed before this is closed.
*
* @throws Exception this is thrown if there is an I/O error
*/
public void commit() throws Exception{
writer.commit(this);
}
/**
* This is used to determine whether this node has been committed.
* If the node is committed then no further child elements can
* be created from this node instance. A node is considered to
* be committed if a parent creates another child element or if
* the commit method is invoked.
*
* @return true if the node has been committed
*/
public boolean isCommitted() {
return writer.isCommitted(this);
}
/**
* This is the string representation of the element. It is
* used for debugging purposes. When evaluating the element
* the to string can be used to print out the element name.
*
* @return this returns a text description of the element
*/
public String toString() {
return String.format("element %s", name);
}
}