104 lines
4.0 KiB
Java
104 lines
4.0 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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import java.util.Stack;
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/**
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* An {@link java.util.Iterator} that iterates over a delegate, and while it encounters an array, a {@link
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* java.util.Collection}, an {@link java.util.Enumeration} or a {@link java.util.Iterator} element, it iterates over it
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* recursively.
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* <p>
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* Be aware that {@link #hasNext()} must read ahead one element.
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*/
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@SuppressWarnings({ "rawtypes", "unchecked" }) public
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class TraversingIterator implements Iterator {
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private final Stack nest = new Stack(); // Iterator
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private Object nextElement;
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private boolean nextElementRead; // Have we read ahead?
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public
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TraversingIterator(Iterator delegate) { this.nest.push(delegate); }
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@Override public boolean
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hasNext() { return this.nextElementRead || this.readNext(); }
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@Override public Object
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next() {
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if (!this.nextElementRead && !this.readNext()) throw new NoSuchElementException();
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this.nextElementRead = false;
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return this.nextElement;
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}
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/**
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* Reads the next element and stores it in {@link #nextElement}.
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* @return <code>false</code> if no more element can be read.
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*/
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private boolean
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readNext() {
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while (!this.nest.empty()) {
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Iterator it = (Iterator) this.nest.peek();
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if (!it.hasNext()) {
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this.nest.pop();
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continue;
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}
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Object o = it.next();
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if (o instanceof Iterator) {
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this.nest.push(o);
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} else
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if (o instanceof Object[]) {
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this.nest.push(Arrays.asList((Object[]) o).iterator());
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} else
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if (o instanceof Collection) {
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this.nest.push(((Collection) o).iterator());
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} else
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if (o instanceof Enumeration) {
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this.nest.push(new EnumerationIterator((Enumeration) o));
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} else
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{
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this.nextElement = o;
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this.nextElementRead = true;
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return true;
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}
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}
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return false;
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}
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/**
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* @throws UnsupportedOperationException iff the {@link Iterator} currently being
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* traversed doesn't support element removal
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* @see Iterator#remove()
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*/
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@Override public void
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remove() { ((Iterator) this.nest.peek()).remove(); }
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}
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