Java BitSet filtered(final Iterator iterator, final BitSet filter)

Description

Returns an Iterator which returns a filtered subset of the given Iterator based on the given filter BitSet

License

Apache License

Parameter

Parameter	Description
iterator	a parameter
filter	a parameter

Return

new instance

Declaration

public static <E> Iterator<E> filtered(final Iterator<E> iterator, final BitSet filter) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2012 Danny Kunz//www. j ava 2  s. c  o m
 * 
 * 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.
 ******************************************************************************/

import java.util.BitSet;

import java.util.Iterator;

import java.util.NoSuchElementException;

public class Main {
    /**
     * Returns an {@link Iterator} which returns a filtered subset of the given {@link Iterator} based on the given filter
     * {@link BitSet}
     * 
     * @param iterator
     * @param filter
     * @return new {@link Iterator} instance
     */
    public static <E> Iterator<E> filtered(final Iterator<E> iterator, final BitSet filter) {
        if (iterator == null) {
            return empty();
        }

        return new Iterator<E>() {
            private int index = 0;
            private boolean hasNoMoreFilteredElements = false;

            @Override
            public boolean hasNext() {
                forwardToNextFilterBit(iterator, filter);
                return !this.hasNoMoreFilteredElements && iterator.hasNext();
            }

            private void forwardToNextFilterBit(final Iterator<E> iterator, final BitSet filter) {
                if (!this.hasNoMoreFilteredElements) {
                    int nextSetBit = -1;
                    while (this.index >= 0 && this.index < (nextSetBit = filter.nextSetBit(this.index))
                            && iterator.hasNext()) {
                        this.fetchElement();
                    }
                    this.hasNoMoreFilteredElements = nextSetBit < 0;
                }
            }

            @Override
            public E next() {
                if (this.hasNext()) {
                    return fetchElement();
                }
                throw new NoSuchElementException();
            }

            private E fetchElement() {
                this.index++;
                return iterator.next();
            }

            @Override
            public void remove() {
                iterator.remove();
            }
        };
    }

    /**
     * Returns an empty {@link Iterator}
     * 
     * @return
     */
    public static <E> Iterator<E> empty() {
        return new Iterator<E>() {
            @Override
            public boolean hasNext() {
                return false;
            }

            @Override
            public E next() {
                throw new NoSuchElementException();
            }

            @Override
            public void remove() {
                throw new UnsupportedOperationException();
            }
        };
    }
}

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2. extractLong(BitSet bitSet, int from, int to)
3. extractSetBitsMsgFromTxSet(final BitSet txSet)
4. filter(double[] data, BitSet mask)
5. filterByIndices(List list, BitSet filter)
6. findTrue(BitSet set)
7. firstIndexOfChar(String sqlString, BitSet keys, int startindex)
8. firstInvalidOctet(CharSequence cs, BitSet bits)
9. formatBitset(BitSet bitset, int width)