| /* |
| * Copyright 2008 Michael Hunger. |
| * |
| * 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 org.qi4j.index.rdf.query.internal; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import static java.lang.String.format; |
| |
| public class Namespaces |
| { |
| private int namespaceCounter = 0; |
| |
| /** |
| * Mapping between namespace and prefix. |
| */ |
| private final Map<String, String> namespaces = new HashMap<String, String>(); |
| |
| public Namespaces() |
| { |
| addDefaultNamespaces(); |
| } |
| |
| private void addDefaultNamespaces() |
| { |
| addNamespace( "rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#" ); |
| addNamespace( "rdfs", "http://www.w3.org/2000/01/rdf-schema#" ); |
| } |
| |
| public Iterable<? extends String> namespaces() |
| { |
| return namespaces.keySet(); |
| } |
| |
| public String addNamespace( final String namespace ) |
| { |
| String prefix = namespacePrefix( namespace ); |
| if( prefix != null ) |
| { |
| return prefix; |
| } |
| prefix = "ns" + namespaceCounter++; |
| return addNamespace( prefix, namespace ); |
| } |
| |
| public String namespacePrefix( String namespace ) |
| { |
| return namespaces.get( namespace ); |
| } |
| |
| public String addNamespace( final String prefix, |
| final String namespace |
| ) |
| { |
| namespaces.put( namespace, prefix ); |
| return prefix; |
| } |
| |
| @Override |
| public String toString() |
| { |
| StringBuilder sb = new StringBuilder(); |
| for( String namespace : namespaces() ) |
| { |
| sb.append( format( "%s:%s%n", namespacePrefix( namespace ), namespace ) ); |
| } |
| return sb.toString(); |
| } |
| } |