66 lines
1.9 KiB
Java
66 lines
1.9 KiB
Java
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/*
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* The Broad Institute
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* SOFTWARE COPYRIGHT NOTICE AGREEMENT
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* This software and its documentation are copyright Jan 22, 2009 by the
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* Broad Institute/Massachusetts Institute of Technology. All rights are reserved.
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*
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* This software is supplied without any warranty or guaranteed support whatsoever. Neither
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* the Broad Institute nor MIT can be responsible for its use, misuse, or functionality.
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*/
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package edu.mit.broad.picard.util;
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import edu.mit.broad.sam.util.CloseableIterator;
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/**
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* Generic Closable Iterator that allows you to peek at the next value before calling next
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*/
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public class PeekableIterator<Object> implements CloseableIterator<Object> {
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private CloseableIterator<Object> iterator;
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private Object nextObject;
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/** Constructs a new iterator that wraps the supplied iterator. */
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public PeekableIterator(CloseableIterator<Object> iterator) {
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this.iterator = iterator;
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advance();
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}
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/** Closes the underlying iterator. */
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public void close() {
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this.iterator.close();
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}
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/** True if there are more items, in which case both next() and peek() will return a value. */
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public boolean hasNext() {
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return this.nextObject != null;
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}
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/** Returns the next object and advances the iterator. */
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public Object next() {
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Object retval = this.nextObject;
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advance();
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return retval;
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}
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/**
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* Returns the next object but does not advance the iterator. Subsequent calls to peek()
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* and next() will return the same object.
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*/
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public Object peek(){
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return this.nextObject;
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}
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private void advance(){
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if (this.iterator.hasNext()) {
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this.nextObject = iterator.next();
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}
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else {
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this.nextObject = null;
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}
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}
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/** Unsupported Operation. */
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public void remove() {
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throw new UnsupportedOperationException("Not supported: remove");
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}
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}
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