src/main/java/org/apache/vysper/xml/fragment/XMLElementVerifier.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.apache.vysper.xml.fragment;

import java.util.List;

/**
 * provides common tools to check a element against its specification or
 * semantical context this classes instances are immutual.
 *
 * TODO add unit test
 *
 * @author The Apache MINA Project (dev@mina.apache.org)
 */
public class XMLElementVerifier {
	protected XMLElement element;

	protected XMLElementVerifier(XMLElement element) {
		if (element == null)
			throw new IllegalArgumentException("null not allowed for element");
		this.element = element;
	}

	public boolean nameEquals(String name) {
		return element.getName().equals(name);
	}

	public boolean attributePresent(String name) {
		return attributePresent("", name);
	}

	public boolean attributePresent(String namespaceUri, String name) {
		return null != element.getAttribute(namespaceUri, name);
	}

	/**
	 * Checks whether all given attributes are present on the element.
	 *
	 * @param names
	 *            the attributes to check
	 * @return true iff all attributes are present, false otherwise
	 */
	public boolean allAttributesPresent(String... names) {
		if (names == null) {
			return false;
		}
		for (String name : names) {
			if (!attributePresent(name)) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Checks whether only the given attributes are present on the element.
	 *
	 * @param names
	 *            the attributes to check
	 * @return true iff only the given attributes are present, false otherwise
	 */
	public boolean onlyAttributesPresent(String... names) {
		if (names == null) {
			return false;
		}
		return element.getAttributes().size() == names.length
				&& allAttributesPresent(names);
	}

	/**
	 * Checks whether any of the given attributes are present on the element.
	 *
	 * @param names
	 *            the attributes to check
	 * @return true iff at least one of the given attributes is present, false
	 *         otherwise
	 */
	public boolean anyAttributePresent(String... names) {
		if (names == null) {
			return false;
		}
		for (String name : names) {
			if (attributePresent(name)) {
				return true;
			}
		}
		return false;
	}

	public boolean attributeEquals(String name, String value) {
		return attributeEquals("", name, value);
	}
	
	public boolean attributeEquals(String namespaceUri, String name, String value) {
		return attributePresent(namespaceUri, name)
				&& element.getAttributeValue(namespaceUri, name).equals(value);
	}

	
	public boolean subElementPresent(String name) {
		for (XMLFragment xmlFragment : element.getInnerFragments()) {
			if (xmlFragment instanceof XMLElement) {
				XMLElement xmlElement = (XMLElement) xmlFragment;
				if (xmlElement.getName().equals(name))
					return true;
			}
		}
		return false;
	}

	public boolean subElementsPresentExact(int numberOfSubelements) {
		return element.getInnerElements().size() == numberOfSubelements;
	}

	public boolean subElementsPresentAtLeast(int numberOfSubelements) {
		return element.getInnerElements().size() >= numberOfSubelements;
	}

	public boolean subElementsPresentAtMost(int numberOfSubelements) {
		return element.getInnerElements().size() <= numberOfSubelements;
	}

	public boolean namespacePresent(String namespaceURI) {
		for (Attribute attribute : element.getAttributes()) {
			if (isNamespaceAttribute(attribute)
					&& attribute.getValue().equals(namespaceURI)) {
				return true;
			}
		}
		
		if(namespaceURI.equals(element.getNamespaceURI())) return true;
		
		return false; // not present
	}

	/**
	 * example for "http://myNS.org/anything", this method returns "myNS" for
	 * element <test xmlns:myNS="http://myNS.org/anything" />
	 *
	 * @return the identifier for the given namespace definition
	 */
	public String getNamespaceIdentifier(String namespace) {
		for (Attribute attribute : element.getAttributes()) {
			if (attribute.getValue().equals(namespace)
					&& attribute.getName().startsWith(
							Namespaces.XMLNS_AND_COLON)) {
				return attribute.getName().substring(
						Namespaces.XMLNS_AND_COLON.length());
			}
		}
		return null;
	}

	private boolean isNamespaceAttribute(Attribute attribute) {
		return (attribute.getName().equalsIgnoreCase(Namespaces.XMLNS) || attribute
				.getName().startsWith(Namespaces.XMLNS_AND_COLON));
	}

	public String getUniqueXMLNSValue() {
		Attribute found = null;
		for (Attribute attribute : element.getAttributes()) {
			if (isNamespaceAttribute(attribute)) {
				if (found != null)
					return null; // not unique
				else {
					found = attribute;
				}
			}
		}
		if (found == null)
			return null;
		return found.getValue();
	}

	public boolean toAttributeEquals(String toValue) {
		return attributeEquals("to", toValue);
	}

	public boolean fromAttributeEquals(String fromValue) {
		return attributeEquals("from", fromValue);
	}

	public boolean onlySubelementEquals(String name, String namespaceURI) {
		List<XMLFragment> innerFragments = element.getInnerFragments();

		// really is only subelement
		if (innerFragments == null || innerFragments.size() != 1) return false;
		XMLFragment onlySubelement = innerFragments.get(0);
		if (!(onlySubelement instanceof XMLElement)) return false;

		XMLElement xmlElement = ((XMLElement) onlySubelement);
        boolean nameEquals = name == null ? xmlElement.getName() == null : name.equals(xmlElement.getName());
        if (namespaceURI == null) namespaceURI = Namespaces.DEFAULT_NAMESPACE_URI;
        return nameEquals && namespaceURI.equals(xmlElement.getNamespaceURI());
	}
}