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/*
* $Id: ElementContext.java,v 1.1 2004/07/15 02:13:54 cniles Exp $
*
* Copyright (c) 2004, Christian Niles, unit12.net
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Christian Niles, Unit12, nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
package javanet.staxutils.helpers;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javanet.staxutils.SimpleNamespaceContext;
import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
/**
* Encapsulates access to contextual element information, such as the element
* name, attributes, and namespaces. This class is useful for recording element
* information in a stack to keep track of the current element c[position in a
* document.
*
* @author Christian Niles
* @version $Revision: 1.1 $
*/
public class ElementContext extends SimpleNamespaceContext {
/** The element name. */
private QName name;
/** The encapsulating context. */
private ElementContext parent;
/** Ordered list of attributes. */
private List attributeNames;
/** Attribute values, keyed by their names. */
private Map attributes;
/** Ordered list of namespace prefixes. */
private List namespacePrefixes;
/** Whether the element is an empty element or not. */
private boolean isEmpty;
/** Whether the context has been closed for further edits. */
private boolean readOnly;
/**
* Constructs a new ElementContext with the provided name and no
* enclosing context.
*
* @param name
* The element name.
*/
public ElementContext(QName name) {
this.name = name;
}
/**
* Constructs a new ElementContext with the provided name and
* empty value, and no enclosing context.
*
* @param name
* The element name.
* @param isEmpty
* Whether the element is an empty element or not.
*/
public ElementContext(QName name, boolean isEmpty) {
this.name = name;
this.isEmpty = isEmpty;
}
/**
* Constructs a new ElementContext with the provided name and
* namespace context.
*
* @param name
* The element name.
* @param context
* The enclosing namespace context.
*/
public ElementContext(QName name, NamespaceContext context) {
super(context);
this.name = name;
}
/**
* Constructs a new ElementContext with the provided name and
* enclosing context.
*
* @param name
* The element name.
* @param parent
* The enclosing element context.
*/
public ElementContext(QName name, ElementContext parent) {
super(parent);
this.name = name;
this.parent = parent;
}
/**
* Constructs a new ElementContext with the provided name and
* enclosing context.
*
* @param name
* The element name.
* @param parent
* The enclosing element context.
* @param isEmpty
* Whether the element is an empty element or not.
*/
public ElementContext(QName name, ElementContext parent, boolean isEmpty) {
super(parent);
this.name = name;
this.parent = parent;
this.isEmpty = isEmpty;
}
/**
* Returns a reference to the enclosing ElementContext.
*
* @return The enclosing context, or null.
*/
public ElementContext getParentContext() {
return parent;
}
/**
* Determines if this context has an enclosing context or not.
*
* @return true if this context is the root context and has no
* enclosing context, false otherwise.
*/
public boolean isRoot() {
return parent == null;
}
/**
* Returns the qualified name associated with the context.
*
* @return The qualified name of the context.
*/
public QName getName() {
return name;
}
/**
* Returns the current context path.
*
* @return A string representing the context path.
*/
public String getPath() {
return appendPath(new StringBuffer()).toString();
}
/**
* @see #getPath()
*/
public String toString() {
return getPath();
}
/**
* Appends the current context path to a {@link StringBuffer}.
*
* @param buffer
* The buffer to which to append the context path.
* @return The provided buffer.
*/
public StringBuffer appendPath(StringBuffer buffer) {
if (parent != null) {
parent.appendPath(buffer);
}
return buffer.append('/').append(name);
}
/**
* Determines the number of enclosing contexts.
*
* @return The number of enclosing contexts.
*/
public int getDepth() {
if (parent == null) {
return 0;
} else {
return parent.getDepth() + 1;
}
}
/**
* Constructs a new child ElementContext with the specified name.
*
* @param name
* The name associated with the child context.
* @return The newly constructed child context.
* @throws IllegalStateException
* If this context is empty.
*/
public ElementContext newSubContext(QName name) {
if (!isEmpty()) {
return new ElementContext(name, this);
} else {
throw new IllegalStateException("ElementContext is empty");
}
}
/**
* Constructs a new child ElementContext with the specified name
* and empty value.
*
* @param name
* The name associated with the child context.
* @param isEmpty
* Whether the child context represents an empty element.
* @return The newly constructed child context.
* @throws IllegalStateException
* If this context is empty.
*/
public ElementContext newSubContext(QName name, boolean isEmpty) {
if (!isEmpty()) {
return new ElementContext(name, this, isEmpty);
} else {
throw new IllegalStateException("ElementContext is empty");
}
}
/**
* Adds an attribute to the context with the specified name and value.
*
* @param name
* The attribute name.
* @param value
* The attribute value.
* @throws IllegalStateException
* If the context is read-only.
*/
public void putAttribute(QName name, String value) {
if (isReadOnly()) {
throw new IllegalStateException("ElementContext is readOnly");
} else if (attributes == null) {
attributes = new HashMap();
attributeNames = new ArrayList();
}
attributeNames.add(name);
attributes.put(name, value);
}
/**
* Adds a namespace declaration to this context with the specified prefix and
* namespace uri.
*
* @param prefix
* The namespace prefix.
* @param nsURI
* The namespace uri.
*/
public void putNamespace(String prefix, String nsURI) {
if (isReadOnly()) {
throw new IllegalStateException("ElementContext is readOnly");
}
if (namespacePrefixes == null) {
namespacePrefixes = new ArrayList();
}
if (prefix.length() == 0) {
// default namespace
namespacePrefixes.add(prefix);
super.setDefaultNamespace(nsURI);
} else {
namespacePrefixes.add(prefix);
super.setPrefix(prefix, nsURI);
}
}
/**
* Returns the number of attributes defined in this context.
*
* @return The number of attributes defined in the context.
*/
public int attributeCount() {
if (attributes != null) {
return attributes.size();
} else {
return 0;
}
}
/**
* Returns the value of the idxth attribute defined on
* the context.
*
* @param idx
* The zero-based index of the attribute value to retrieve.
* @return The value of the idxth attribute defined on
* the context.
* @throws IndexOutOfBoundsException
* If the index is out of bounds.
*/
public String getAttribute(int idx) {
return getAttribute(getAttributeName(idx));
}
/**
* Returns the name of the idxth attribute defined on
* the context.
*
* @param idx
* The zero-based index of the attribute name to retrieve.
* @return The name of the idxth attribute defined on
* the context.
* @throws IndexOutOfBoundsException
* If the index is out of bounds.
*/
public QName getAttributeName(int idx) {
if (attributeNames != null) {
return (QName) attributeNames.get(idx);
} else {
throw new IndexOutOfBoundsException("Attribute index " + idx + " doesn't exist");
}
}
/**
* Returns the value of a named attribute.
*
* @param name
* The name of the attribute value to retrieve.
* @return The value of the named attribute, or null.
*/
public String getAttribute(QName name) {
if (attributes != null) {
return (String) attributes.get(name);
} else {
return null;
}
}
/**
* Determines if an attribute with the specified name exists in this context.
*
* @param name
* The name of the attribute.
* @return true if an attribute with the specified name has been
* defined in this context, false otherwise.
*/
public boolean attributeExists(QName name) {
if (attributes != null) {
return attributes.containsKey(name);
} else {
return false;
}
}
/**
* Returns an {@link Iterator} over the names of all attributes defined in
* this context. The returned iterator will not support the
* {@link Iterator#remove()} operation.
*
* @return An {@link Iterator} over the names of all attributes defined in
* this context.
*/
public Iterator attributeNames() {
if (attributeNames != null) {
return Collections.unmodifiableList(attributeNames).iterator();
} else {
return Collections.EMPTY_LIST.iterator();
}
}
/**
* Determines the number of namespaces declared in this context.
*
* @return The number of namespaces declared in this context.
*/
public int namespaceCount() {
if (namespacePrefixes != null) {
return namespacePrefixes.size();
} else {
return 0;
}
}
/**
* Returns the URI of the idxth namespace declaration
* defined in this context.
*
* @param idx
* The index of the namespace URI to return.
* @return The URI of the idxth namespace declaration
* defined in this context.
* @throws IndexOutOfBoundsException
* If the index is out of bounds.
*/
public String getNamespaceURI(int idx) {
return this.getNamespaceURI(getNamespacePrefix(idx));
}
/**
* Returns the prefix of the idxth namespace
* declaration defined in this context.
*
* @param idx
* The index of the namespace prefix to return.
* @return The prefix of the idxth namespace
* declaration defined in this context.
* @throws IndexOutOfBoundsException
* If the index is out of bounds.
*/
public String getNamespacePrefix(int idx) {
if (namespacePrefixes != null) {
return (String) namespacePrefixes.get(idx);
} else {
throw new IndexOutOfBoundsException("Namespace index " + idx + " doesn't exist");
}
}
/**
* Whether this context may be edited or not.
*
* @return true if no additional modifications may be made to
* this context, false otherwise.
*/
public boolean isReadOnly() {
return readOnly;
}
/**
* Prevents any further additions to this context.
*/
public void setReadOnly() {
this.readOnly = true;
}
/**
* Whether this context represents an emtpy element. Empty contexts may not
* enclose any other contexts.
*
* @return true if this context represents an emtpy element,
* false otherwise.
*/
public boolean isEmpty() {
return isEmpty;
}
}