/*
 * 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 freemarker.ext.xml;
import java.util.HashMap;
import java.util.List;

import freemarker.template.TemplateMethodModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateScalarModel;

/**
 */
class Namespaces
implements
    TemplateMethodModel,
    Cloneable {
    private HashMap namespaces;
    private boolean shared;
        
    Namespaces() {
        namespaces = new HashMap();
        namespaces.put("", "");
        namespaces.put("xml", "http://www.w3.org/XML/1998/namespace");
        shared = false;
    }
        
    @Override
    public Object clone() {
        try {
            Namespaces clone = (Namespaces) super.clone();
            clone.namespaces = (HashMap) namespaces.clone();
            clone.shared = false;
            return clone;
        } catch (CloneNotSupportedException e) {
            throw new Error(); // Cannot happen
        }
    }
    
    public String translateNamespacePrefixToUri(String prefix) {
        synchronized (namespaces) {
            return (String) namespaces.get(prefix);
        }   
    }
    
    public Object exec(List arguments) throws TemplateModelException {
        if (arguments.size() != 2) {
            throw new TemplateModelException("_registerNamespace(prefix, uri) requires two arguments");
        }
        registerNamespace((String) arguments.get(0), (String) arguments.get(1));
        return TemplateScalarModel.EMPTY_STRING;
    }
    
    void registerNamespace(String prefix, String uri) {
        synchronized (namespaces) {
            namespaces.put(prefix, uri);
        }   
    }
    
    void markShared() {
        if (!shared) {
            shared = true;
        }
    }
    
    boolean isShared() {
        return shared;
    }
}