/*
* Copyright (c) 2009, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.ejb.packaging;
import java.util.ArrayList;
import java.util.Iterator;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* A utility class to cover up the rough bits of xml parsing
*
* @author <a href="mailto:chris@kimptoc.net">Chris Kimpton</a>
*/
public final class XmlHelper {
private XmlHelper() {
}
/**
* Returns an iterator over the children of the given element with
* the given tag name.
*
* @param element The parent element
* @param tagName The name of the desired child
* @return An interator of children or null if element is null.
*/
public static Iterator getChildrenByTagName(
Element element,
String tagName) {
if ( element == null ) return null;
// getElementsByTagName gives the corresponding elements in the whole
// descendance. We want only children
NodeList children = element.getChildNodes();
ArrayList goodChildren = new ArrayList();
for ( int i = 0; i < children.getLength() ; i++ ) {
Node currentChild = children.item( i );
if ( currentChild.getNodeType() == Node.ELEMENT_NODE &&
( (Element) currentChild ).getTagName().equals( tagName ) ) {
goodChildren.add( (Element) currentChild );
}
}
return goodChildren.iterator();
}
/**
* Gets the child of the specified element having the specified unique
* name. If there are more than one children elements with the same name
* and exception is thrown.
*
* @param element The parent element
* @param tagName The name of the desired child
* @return The named child.
* @throws Exception Child was not found or was not unique.
*/
public static Element getUniqueChild(Element element, String tagName)
throws Exception {
Iterator goodChildren = getChildrenByTagName( element, tagName );
if ( goodChildren != null && goodChildren.hasNext() ) {
Element child = (Element) goodChildren.next();
if ( goodChildren.hasNext() ) {
throw new Exception
( "expected only one " + tagName + " tag" );
}
return child;
}
else {
throw new Exception
( "expected one " + tagName + " tag" );
}
}
/**
* Gets the child of the specified element having the
* specified name. If the child with this name doesn't exist
* then null is returned instead.
*
* @param element the parent element
* @param tagName the name of the desired child
* @return either the named child or null
*/
public static Element getOptionalChild(Element element, String tagName)
throws Exception {
return getOptionalChild( element, tagName, null );
}
/**
* Gets the child of the specified element having the
* specified name. If the child with this name doesn't exist
* then the supplied default element is returned instead.
*
* @param element the parent element
* @param tagName the name of the desired child
* @param defaultElement the element to return if the child
* doesn't exist
* @return either the named child or the supplied default
*/
public static Element getOptionalChild(
Element element,
String tagName,
Element defaultElement) throws Exception {
Iterator goodChildren = getChildrenByTagName( element, tagName );
if ( goodChildren != null && goodChildren.hasNext() ) {
Element child = (Element) goodChildren.next();
if ( goodChildren.hasNext() ) {
throw new Exception
( "expected only one " + tagName + " tag" );
}
return child;
}
else {
return defaultElement;
}
}
/**
* Get the content of the given element.
*
* @param element The element to get the content for.
* @return The content of the element or null.
*/
public static String getElementContent(final Element element)
throws Exception {
return getElementContent( element, null );
}
/**
* Get the content of the given element.
*
* @param element The element to get the content for.
* @param defaultStr The default to return when there is no content.
* @return The content of the element or the default.
*/
public static String getElementContent(Element element, String defaultStr)
throws Exception {
if ( element == null ) {
return defaultStr;
}
NodeList children = element.getChildNodes();
StringBuilder result = new StringBuilder("");
for ( int i = 0; i < children.getLength() ; i++ ) {
if ( children.item( i ).getNodeType() == Node.TEXT_NODE ||
children.item( i ).getNodeType() == Node.CDATA_SECTION_NODE ) {
result.append( children.item( i ).getNodeValue() );
}
// else if ( children.item( i ).getNodeType() == Node.COMMENT_NODE ) {
// // Ignore comment nodes
// }
}
return result.toString().trim();
}
/**
* Macro to get the content of a unique child element.
*
* @param element The parent element.
* @param tagName The name of the desired child.
* @return The element content or null.
*/
public static String getUniqueChildContent(
Element element,
String tagName) throws Exception {
return getElementContent( getUniqueChild( element, tagName ) );
}
/**
* Macro to get the content of an optional child element.
*
* @param element The parent element.
* @param tagName The name of the desired child.
* @return The element content or null.
*/
public static String getOptionalChildContent(
Element element,
String tagName) throws Exception {
return getElementContent( getOptionalChild( element, tagName ) );
}
public static boolean getOptionalChildBooleanContent(Element element, String name) throws Exception {
Element child = getOptionalChild( element, name );
if ( child != null ) {
String value = getElementContent( child ).toLowerCase();
return value.equals( "true" ) || value.equals( "yes" );
}
return false;
}
}