All Downloads are FREE. Search and download functionalities are using the official Maven repository.

jodd.util.LoopIterator Maven / Gradle / Ivy

There is a newer version: 5.3.0
Show newest version
// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

package jodd.util;

/**
 * Loop iterator that provides various counting data about the loop cycles.
 * Should be used as in while construct:
 *
 * 

 * while (loopIterator.next()) {
 * 		// do something
 * }
 * 
*/ public class LoopIterator { protected final int start; protected final int end; protected final int step; protected final int modulus; protected boolean first; protected boolean last; protected int value; protected int count; protected final boolean looping; public LoopIterator(final int start, final int end) { this(start, end, 1, 2); } public LoopIterator(final int start, final int end, final int step) { this(start, end, step, 2); } public LoopIterator(final int start, final int end, final int step, final int modulus) { this.start = start; this.end = end; this.step = step; this.modulus = modulus; this.looping = step > 0 ? start <= end : start >= end; } /** * Returns current item count (1-based). */ public int getCount() { return count; } /** * Returns current item index (0-based). */ public int getIndex() { return count - 1; } /** * Returns current loop value. */ public int getValue() { return value; } /** * Returns true if current count is even. */ public boolean isEven() { return (count % 2) == 0; } /** * Returns true if current count is odd. */ public boolean isOdd() { return (count % 2) == 1; } /** * Calculates modulus of current count. */ public int modulus(final int operand) { return count % operand; } /** * Returns modulus of current count. */ public int getModulus() { return count % modulus; } /** * Returns modulus value. */ public int getModulusValue() { return modulus; } /** * Returns modulus of current index. */ public int getIndexModulus() { return (count - 1) % modulus; } /** * Returns true if current item is the first one. */ public boolean isFirst() { return first; } /** * Returns true if current item is the last one. */ public boolean isLast() { return last; } // ---------------------------------------------------------------- iterate /** * Iterates to next value at the beginning of the loop. */ public boolean next() { if (!looping) { return false; } if (last) { return false; } if (count == 0) { value = start; first = true; } else { value += step; first = false; } count++; last = isLastIteration(value + step); return true; } /** * Resets the loop from the beginning. */ public void reset() { count = 0; last = false; } protected boolean isLastIteration(final int value) { return step > 0 ? value > end : value < end; } @Override public String toString() { return looping ? value + ":" + count + ':' + (first ? 'F':'_') + ':' + (last ? 'L':'_') + ':' + getModulus() : "N.A."; } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy