package org.apache.onami.configuration;

 /*

  * 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.

  */

 import java.util.Iterator;

 import java.util.Map;

 import java.util.Map.Entry;

 /**

  * Simple iterator of a {@code Map<K, V>} entries, with the option of prefixing keys

  * with the given prefix.

  */

 final class PropertiesIterator<K, V>

     implements Iterator<Entry<String, String>>

 {

     /**

      * Creates a new iterator over a map configuration with prefixing the keys with the given prefix.

      *

      * @param <K> The map entry key type

      * @param <V> The map entry value type

      * @param properties The map configuration has to be read

      * @return A map configuration iterator

      */

     public static final <K, V> PropertiesIterator<K, V> newPropertiesIterator( Map<K, V> properties )

     {

         return new PropertiesIterator<K, V>( null, properties );

     }

     /**

      * Creates a new iterator over a map configuration with prefixing the keys with the given prefix.

      *

      * @param <K> the map entry key type.

      * @param <V> the map entry value type.

      * @param keyPrefix the prefix for key entries.

      * @param properties the map configuration has to be read.

      * @return a map configuration iterator.

      */

     public static final <K, V> PropertiesIterator<K, V> newPropertiesIterator( String keyPrefix, Map<K, V> properties )

     {

         return new PropertiesIterator<K, V>( keyPrefix, properties );

     }

     /**

      * The key prefix.

      */

     private final String keyPrefix;

     /**

      * The wrapped configuration iterator.

      */

     private final Iterator<Entry<K, V>> propertiesIterator;

     /**

      * Creates a new properties iterator.

      *

      * @param keyPrefix the key prefix. It can be {@code null}.

      * @param properties the wrapped configuration.

      */

     private PropertiesIterator( String keyPrefix, Map<K, V> properties )

     {

         this.keyPrefix = keyPrefix;

         this.propertiesIterator = properties.entrySet().iterator();

     }

     /**

      * {@inheritDoc}

      */

     public boolean hasNext()

     {

         return propertiesIterator.hasNext();

     }

     /**

      * {@inheritDoc}

      */

     public Entry<String, String> next()

     {

         Entry<K, V> next = propertiesIterator.next();

         String key = String.valueOf( next.getKey() );

         if ( keyPrefix != null && keyPrefix.length() > 0 )

         {

             key = keyPrefix + key;

         }

         return new KeyValue( key, String.valueOf( next.getValue() ) );

     }

     /**

      * {@inheritDoc}

      */

     public void remove() {

         // not needed in this version

     }

 }