001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.collections.primitives;
018    
019    /**
020     * An iterator over <code>boolean</code> values.
021     *
022     * @see org.apache.commons.collections.primitives.adapters.BooleanIteratorIterator
023     * @see org.apache.commons.collections.primitives.adapters.IteratorBooleanIterator
024     *
025     * @since Commons Primitives 1.1
026     * @version $Revision: 480460 $ $Date: 2006-11-29 09:14:21 +0100 (Wed, 29 Nov 2006) $
027     */
028    public interface BooleanIterator {
029        /** 
030         * Returns <code>true</code> iff I have more elements.  (In other words,
031         * returns <code>true</code> iff a subsequent call to {@link #next next}
032         * will return an element rather than throwing an exception.)
033         * 
034         * @return <code>true</code> iff I have more elements
035         */
036        boolean hasNext();
037        
038        /** 
039         * Returns the next element in me.
040         * 
041         * @return the next element in me
042         * @throws java.util.NoSuchElementException if there is no next element
043         */          
044        boolean next();
045        
046        /** 
047         * Removes from my underlying collection the last element {@link #next
048         * returned} by me (optional operation).
049         * 
050         * @throws UnsupportedOperationException if this operation is not supported
051         * @throws IllegalStateException if {@link #next} has not yet been called,
052         *         or {@link #remove} has already been called since the last call
053         *         to {@link #next}.
054         */          
055        void remove();
056    }