com.jkoolcloud.tnt4j.streams.utils.NamespaceMap.java Source code

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Here is the source code for com.jkoolcloud.tnt4j.streams.utils.NamespaceMap.java

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/*
 * Copyright 2014-2018 JKOOL, LLC.
 *
 * 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 com.jkoolcloud.tnt4j.streams.utils;

import java.util.*;

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

import org.apache.commons.collections4.CollectionUtils;

/**
 * Implements {@link NamespaceContext}, where every namespace prefix and URI relation is resolved from internally stored
 * {@link Map}.
 *
 * @version $Revision: 1 $
 */
public final class NamespaceMap implements NamespaceContext {
    private static final List<String> EMPTY_NS_LIST = Collections.singletonList(XMLConstants.DEFAULT_NS_PREFIX);

    private final Map<String, String> mapNS = new HashMap<>(10);
    private final Map<String, Set<String>> mapURI = new HashMap<>(10);

    /**
     * Constructs a new namespaces map.
     */
    public NamespaceMap() {
    }

    /**
     * Sets mapping of namespace prefix to namespace URI.
     *
     * @param prefix
     *            prefix to put into mapping
     * @param uri
     *            uri to put into mapping
     */
    public String setPrefixUriMapping(String prefix, String uri) {
        mapURI(prefix, uri);
        return mapNS.put(prefix, uri);
    }

    /**
     * Adds mapping of namespace prefix to namespace URI. If mapping already exists, does nothing.
     *
     * @param prefix
     *            prefix to put into mapping
     * @param uri
     *            uri to put into mapping
     * @return {@code true} if mapping was added, {@code false} - otherwise
     */
    public boolean addPrefixUriMapping(String prefix, String uri) {
        if (!mapNS.containsKey(prefix)) {
            setPrefixUriMapping(prefix, uri);
            return true;
        }

        return false;
    }

    /**
     * Returns mapping of namespace prefix to namespace URI.
     *
     * @param prefix
     *            prefix to get mapping uri
     * @return mapped uri, or {@code null} if there is no namespace prefix mapping defined
     */
    public String getPrefixUriMapping(String prefix) {
        return mapNS.get(prefix);
    }

    /**
     * Adds mappings of namespace prefix to namespace URI.
     *
     * @param nsMap
     *            map containing namespace prefix to namespace URI mappings
     */
    public void addPrefixUriMappings(Map<String, String> nsMap) {
        mapNS.putAll(nsMap);

        for (Map.Entry<String, String> nsms : nsMap.entrySet()) {
            mapURI(nsms.getKey(), nsms.getValue());
        }
    }

    private void mapURI(String prefix, String uri) {
        Set<String> prefixList = mapURI.get(uri);
        if (prefixList == null) {
            prefixList = new LinkedHashSet<>(5);
            mapURI.put(uri, prefixList);
        }
        prefixList.add(prefix);
    }

    @Override
    public String getNamespaceURI(String prefix) {
        String uri = mapNS.get(prefix);
        if (uri == null) {
            uri = XMLConstants.XML_NS_URI;
        }
        return uri;
    }

    @Override
    public String getPrefix(String namespaceURI) {
        Set<String> nsList = mapURI.get(namespaceURI);
        return CollectionUtils.isEmpty(nsList) ? XMLConstants.DEFAULT_NS_PREFIX : nsList.iterator().next();
    }

    @Override
    public Iterator<String> getPrefixes(String namespaceURI) {
        Set<String> nsList = mapURI.get(namespaceURI);
        return nsList == null ? EMPTY_NS_LIST.iterator() : nsList.iterator();
    }
}