| // Copyright 2006 The Apache Software Foundation |
| // |
| // 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.apache.tapestry5.internal.util; |
| |
| import java.util.Iterator; |
| |
| /** |
| * Represents a sequence of integer values, either ascending or descending. The sequence is always inclusive (of the |
| * finish value). |
| */ |
| public final class IntegerRange implements Iterable<Integer> |
| { |
| private final int start; |
| |
| private final int finish; |
| |
| private class RangeIterator implements Iterator<Integer> |
| { |
| private final int increment; |
| |
| private int value = start; |
| |
| private boolean hasNext = true; |
| |
| RangeIterator() |
| { |
| increment = start < finish ? +1 : -1; |
| } |
| |
| public boolean hasNext() |
| { |
| return hasNext; |
| } |
| |
| public Integer next() |
| { |
| if (!hasNext) throw new IllegalStateException(); |
| |
| int result = value; |
| |
| hasNext = value != finish; |
| |
| value += increment; |
| |
| return result; |
| } |
| |
| public void remove() |
| { |
| throw new UnsupportedOperationException(); |
| } |
| |
| } |
| |
| public IntegerRange(final int start, final int finish) |
| { |
| this.start = start; |
| this.finish = finish; |
| } |
| |
| public int getFinish() |
| { |
| return finish; |
| } |
| |
| public int getStart() |
| { |
| return start; |
| } |
| |
| @Override |
| public String toString() |
| { |
| return String.format("%d..%d", start, finish); |
| } |
| |
| /** |
| * The main puprose of a range object is to produce an Iterator. Since IntegerRange is iterable, it is useful with |
| * the Tapestry Loop component, but also with the Java for loop! |
| */ |
| public Iterator<Integer> iterator() |
| { |
| return new RangeIterator(); |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| final int PRIME = 31; |
| |
| int result = PRIME + finish; |
| |
| result = PRIME * result + start; |
| |
| return result; |
| } |
| |
| /** |
| * Returns true if the other object is an IntegerRange with the same start and finish values. |
| */ |
| @Override |
| public boolean equals(Object obj) |
| { |
| if (this == obj) return true; |
| if (obj == null) return false; |
| if (getClass() != obj.getClass()) return false; |
| final IntegerRange other = (IntegerRange) obj; |
| if (finish != other.finish) return false; |
| |
| return start == other.start; |
| } |
| |
| } |