com.greenpepper.shaded.org.codehaus.janino.util.iterator.MultiDimensionalIterator Maven / Gradle / Ivy
/*
* Janino - An embedded Java[TM] compiler
*
* Copyright (c) 2001-2010, Arno Unkrig
* 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.
* 3. The name of the author may not be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 com.greenpepper.shaded.org.codehaus.janino.util.iterator;
import java.util.Arrays;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* An {@link java.util.Iterator} that iterates over a delegate, which produces
* arrays, {@link java.util.Collection}s, {@link java.util.Enumeration}s or
* {@link java.util.Iterator}s. This {@link java.util.Iterator} returns the
* elements of these objects.
*
* The count of dimensions is declared at construction. Count "1" produces an
* {@link java.util.Iterator} that adds no functionality to its delegate, count
* "2" produces an {@link Iterator} that behaves as explained above, and so
* forth.
*/
@SuppressWarnings("rawtypes") public
class MultiDimensionalIterator implements Iterator {
private final Iterator[] nest;
private static final Iterator EMPTY_ITERATOR = new Iterator() {
@Override public boolean hasNext() { return false; }
@Override public Object next() { throw new NoSuchElementException(); }
@Override public void remove() { throw new UnsupportedOperationException("remove"); }
};
public
MultiDimensionalIterator(Iterator delegate, int dimensionCount) {
this.nest = new Iterator[dimensionCount];
this.nest[0] = delegate;
for (int i = 1; i < dimensionCount; ++i) this.nest[i] = MultiDimensionalIterator.EMPTY_ITERATOR;
}
/** @throws UniterableElementException */
@SuppressWarnings("unchecked") @Override public boolean
hasNext() {
// Unroll this check because it is so performance critical:
if (this.nest[this.nest.length - 1].hasNext()) return true;
int i = this.nest.length - 2;
if (i < 0) return false;
for (;;) {
if (!this.nest[i].hasNext()) {
if (i == 0) return false;
--i;
} else {
if (i == this.nest.length - 1) return true;
Object o = this.nest[i].next();
if (o instanceof Iterator) {
this.nest[++i] = (Iterator) o;
} else
if (o instanceof Object[]) {
this.nest[++i] = Arrays.asList((Object[]) o).iterator();
} else
if (o instanceof Collection) {
this.nest[++i] = ((Collection) o).iterator();
} else
if (o instanceof Enumeration) {
this.nest[++i] = new EnumerationIterator