configurablenamespacecontext.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.common.metadata;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;

/**
 * {@code ConfigurableNamespaceContext} is a custom {@link NamespaceContext}
 * that is designed to be configured via a JSF configuration file or similar
 * mechanism.
 * <p>
 * This is a fairly minimal implementation of {@code NamespaceContext}.  
 * {@link #getPrefix(String)} and {@link #getPrefixes(String)} always
 * throw an {@link UnsupportedOperationException}.  The reason for this
 * is because this {@link NamespaceContext} was mainly written to support
 * DOM-based XPath parsing, which does not require the aforementioned methods.
 * </p> 
 */
public class ConfigurableNamespaceContext implements NamespaceContext {

	/**
	 * {@link Map} containing the namespaces.
	 */
	private Map<String, String> _namespaces = new HashMap<String, String>();

	/**
	 * Default no-arg constructor.
	 */
	public ConfigurableNamespaceContext() {
		_namespaces.put(XMLConstants.XML_NS_PREFIX, XMLConstants.XML_NS_URI);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see javax.xml.namespace.NamespaceContext#getNamespaceURI(java.lang.String)
	 */
	public String getNamespaceURI(String prefix) {
		if (prefix == null) {
			throw new NullPointerException("prefix cannot be null");
		}
		String uri = _namespaces.get(prefix);
		if (uri == null) {
			uri = "";
		}
		return uri;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see javax.xml.namespace.NamespaceContext#getPrefix(java.lang.String)
	 * @throws UnsupportedOperationException
	 *             in every case.
	 */
	public String getPrefix(String uri) {
		throw new UnsupportedOperationException();
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see javax.xml.namespace.NamespaceContext#getPrefixes(java.lang.String)
	 * @throws UnsupportedOperationException
	 *             in every case.
	 */
	@SuppressWarnings("unchecked")
	public Iterator getPrefixes(String uri) {
		throw new UnsupportedOperationException();
	}

	/**
	 * Adds the contents of a {@link Map} to the namespace registry.
	 * <p>
	 * The key in the {@link Map} parameter must be of type {@link String} and
	 * must contain the namespace prefix. The value must be a {@link String}
	 * that contains the namespace URI.
	 * 
	 * @param namespaces
	 *            {@code Map<String, String>} containing the namespaces. Cannot
	 *            be {@code null}.
	 */
	public void setRegistry(Map<String, String> namespaces) {
		if (namespaces == null) {
			throw new NullPointerException("Namespaces cannot be null");
		}
		_namespaces.putAll(namespaces);
	}

	/**
	 * Adds an item to the namespace registry.
	 * @param prefix The prefix of the namespace that is being added to the registry.  Cannot be {@code null}
	 * @param uri The namespace uri.  Cannot be {@code null}.
	 */
	public void register(String prefix, String uri) {
		if (prefix == null) {
			throw new NullPointerException("prefix cannot be null");
		}
		if (uri == null) {
			throw new NullPointerException("uri cannot be null");
		}
		_namespaces.put(prefix, uri);
	}

	/**
	 * Removes an item from the namespace registry.
	 * @param prefix The namespace prefix (i.e. &quot;xml&quot; or &quot;gml&quot;) 
	 * of the namespace that should be removed.  Cannot be {@code null}.
	 */
	public void unregister(String prefix) {
		if (prefix == null) {
			throw new NullPointerException("prefix cannot be null");
		}
		_namespaces.remove(prefix);
	}

	/**
	 * Removes all items from the namespace registry.
	 */
	public void clear() {
		_namespaces.clear();
	}
}