106 lines
4.4 KiB
Java
106 lines
4.4 KiB
Java
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/*
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* Janino - An embedded Java[TM] compiler
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*
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* Copyright (c) 2001-2010, Arno Unkrig
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
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* following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
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* following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
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* following disclaimer in the documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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package org.codehaus.janino.util.iterator;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Enumeration;
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import java.util.Iterator;
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import java.util.NoSuchElementException;
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/**
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* An {@link java.util.Iterator} that iterates over a delegate, which produces
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* arrays, {@link java.util.Collection}s, {@link java.util.Enumeration}s or
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* {@link java.util.Iterator}s. This {@link java.util.Iterator} returns the
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* elements of these objects.
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* <p>
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* The count of dimensions is declared at construction. Count "1" produces an
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* {@link java.util.Iterator} that adds no functionality to its delegate, count
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* "2" produces an {@link Iterator} that behaves as explained above, and so
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* forth.
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*/
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@SuppressWarnings("rawtypes") public
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class MultiDimensionalIterator implements Iterator {
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private final Iterator[] nest;
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private static final Iterator EMPTY_ITERATOR = new Iterator() {
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@Override public boolean hasNext() { return false; }
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@Override public Object next() { throw new NoSuchElementException(); }
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@Override public void remove() { throw new UnsupportedOperationException("remove"); }
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};
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public
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MultiDimensionalIterator(Iterator delegate, int dimensionCount) {
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this.nest = new Iterator[dimensionCount];
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this.nest[0] = delegate;
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for (int i = 1; i < dimensionCount; ++i) this.nest[i] = MultiDimensionalIterator.EMPTY_ITERATOR;
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}
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/** @throws UniterableElementException */
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@SuppressWarnings("unchecked") @Override public boolean
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hasNext() {
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// Unroll this check because it is so performance critical:
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if (this.nest[this.nest.length - 1].hasNext()) return true;
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int i = this.nest.length - 2;
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if (i < 0) return false;
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for (;;) {
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if (!this.nest[i].hasNext()) {
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if (i == 0) return false;
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--i;
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} else {
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if (i == this.nest.length - 1) return true;
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Object o = this.nest[i].next();
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if (o instanceof Iterator) {
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this.nest[++i] = (Iterator) o;
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} else
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if (o instanceof Object[]) {
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this.nest[++i] = Arrays.asList((Object[]) o).iterator();
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} else
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if (o instanceof Collection) {
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this.nest[++i] = ((Collection) o).iterator();
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} else
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if (o instanceof Enumeration) {
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this.nest[++i] = new EnumerationIterator<Object>((Enumeration) o);
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} else
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{
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throw new UniterableElementException();
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}
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}
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}
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}
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@Override public Object
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next() {
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if (!this.hasNext()) throw new NoSuchElementException();
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return this.nest[this.nest.length - 1].next();
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}
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@Override public void remove() { throw new UnsupportedOperationException("remove"); }
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}
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