Example usage for java.util Iterator Iterator

Introduction

In this page you can find the example usage for java.util Iterator Iterator.

Prototype

Iterator

Source Link

Usage

From source file:org.apache.pig.backend.hadoop.executionengine.HJob.java

@Override
public Iterator<Tuple> getResults() throws ExecException {
    final LoadFunc p;

    try {//w ww . j  a v  a2 s  .c  o m
        LoadFunc originalLoadFunc = (LoadFunc) PigContext.instantiateFuncFromSpec(outFileSpec.getFuncSpec());

        p = (LoadFunc) new ReadToEndLoader(originalLoadFunc,
                ConfigurationUtil.toConfiguration(pigContext.getProperties()), outFileSpec.getFileName(), 0);

    } catch (Exception e) {
        int errCode = 2088;
        String msg = "Unable to get results for: " + outFileSpec;
        throw new ExecException(msg, errCode, PigException.BUG, e);
    }

    return new Iterator<Tuple>() {
        Tuple t;
        boolean atEnd;

        @Override
        public boolean hasNext() {
            if (atEnd)
                return false;
            try {
                if (t == null)
                    t = p.getNext();
                if (t == null)
                    atEnd = true;
            } catch (Exception e) {
                log.error(e);
                t = null;
                atEnd = true;
                throw new Error(e);
            }
            return !atEnd;
        }

        @Override
        public Tuple next() {
            Tuple next = t;
            if (next != null) {
                t = null;
                return next;
            }
            try {
                next = p.getNext();
            } catch (Exception e) {
                log.error(e);
            }
            if (next == null)
                atEnd = true;
            return next;
        }

        @Override
        public void remove() {
            throw new RuntimeException("Removal not supported");
        }

    };
}

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From source file:hudson.matrix.AxisList.java

/**
 * List up all the possible combinations of this list.
 *//*from   w  w  w  .  j a  v  a 2 s . c  om*/
public Iterable<Combination> list() {
    final int[] base = new int[size()];
    if (base.length == 0)
        return Collections.<Combination>emptyList();

    int b = 1;
    for (int i = size() - 1; i >= 0; i--) {
        base[i] = b;
        b *= get(i).size();
    }

    final int total = b; // number of total combinations

    return new Iterable<Combination>() {
        public Iterator<Combination> iterator() {
            return new Iterator<Combination>() {
                private int counter = 0;

                public boolean hasNext() {
                    return counter < total;
                }

                public Combination next() {
                    String[] data = new String[size()];
                    int x = counter++;
                    for (int i = 0; i < data.length; i++) {
                        data[i] = get(i).value(x / base[i]);
                        x %= base[i];
                    }
                    assert x == 0;
                    return new Combination(AxisList.this, data);
                }

                public void remove() {
                    throw new UnsupportedOperationException();
                }
            };
        }
    };
}

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From source file:hudson.model.RunMap.java

/**
 * Walks through builds, newer ones first.
 *///from w w  w  .  ja v a 2s. c  o  m
public Iterator<R> iterator() {
    return new Iterator<R>() {
        R last = null;
        R next = newestBuild();

        public boolean hasNext() {
            return next != null;
        }

        public R next() {
            last = next;
            if (last != null)
                next = last.getPreviousBuild();
            else
                throw new NoSuchElementException();
            return last;
        }

        public void remove() {
            if (last == null)
                throw new UnsupportedOperationException();
            removeValue(last);
        }
    };
}

---

From source file:Iterators.java

/**
 * Returns an unmodifiable view of the specified iterator.
 * Calls to {@code next()} and {@code hasNext()} are delegated
 * to the specified iterator as made.  Calls to {@code remove()}
 * throw unsupported operation exceptions.
 *
 * @param it Iterator to view./*ww  w  .  ja va  2  s .  c  om*/
 * @return Unmodifiable view of specified iterator.
 */
public static <E> Iterator<E> unmodifiable(Iterator<E> it) {
    final Iterator<E> mIt = it;
    return new Iterator<E>() {
        public boolean hasNext() {
            return mIt.hasNext();
        }

        public E next() {
            return mIt.next();
        }

        public void remove() {
            String msg = "Cannot remove from an unmodifiable iterator.";
            throw new UnsupportedOperationException(msg);
        }
    };
}

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From source file:hudson.util.CopyOnWriteList.java

/**
 * Returns an iterator./* w  ww  . j  a va2s  . co m*/
 */
public Iterator<E> iterator() {
    final Iterator<? extends E> itr = core.iterator();
    return new Iterator<E>() {
        private E last;

        public boolean hasNext() {
            return itr.hasNext();
        }

        public E next() {
            return last = itr.next();
        }

        public void remove() {
            CopyOnWriteList.this.remove(last);
        }
    };
}

---

From source file:com.clxcommunications.xms.PagedFetcher.java

/**
 * Returns an iterable object that traverses all fetched elements across all
 * associated pages. This is done by iterating over fetched pages and, when
 * necessary, fetching new pages.//from   ww  w .  ja v  a2 s .  c  o m
 * <p>
 * Since multiple fetches may be necessary to iterate over all batches it is
 * possible that concurrent changes on the server will cause the same batch
 * to be iterated over twice.
 * <p>
 * ALso, since the returned iterator will perform asynchronous network
 * traffic it is possible that the {@link Iterator#hasNext()} and
 * {@link Iterator#next()} methods throws {@link RuntimeException} having as
 * cause an {@link ExecutionException}.
 * 
 * @return a non-null iterable
 * @throws RuntimeException
 *             if the background page fetching failed
 */
@Nonnull
public Iterable<T> elements() {

    return new Iterable<T>() {

        @Override
        public Iterator<T> iterator() {

            final Iterator<Page<T>> pageIt = pages().iterator();

            return new Iterator<T>() {

                Iterator<T> pageElemIt = pageIt.next().iterator();

                @Override
                public boolean hasNext() {
                    if (!pageElemIt.hasNext()) {
                        if (!pageIt.hasNext()) {
                            return false;
                        } else {
                            pageElemIt = pageIt.next().iterator();
                            return pageElemIt.hasNext();
                        }
                    } else {
                        return true;
                    }
                }

                @Override
                public T next() {
                    if (!pageElemIt.hasNext()) {
                        pageElemIt = pageIt.next().iterator();
                    }

                    return pageElemIt.next();
                }

            };

        }

    };
}

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From source file:com.conwet.silbops.model.Advertise.java

/**
 * @throws UnsupportedOperationException since there is no real need to
 * duplicate elements.//from  www  . j ava2s. c  om
 */
@Override
public Set<Entry<Attribute, Attribute>> entries() {

    return new AbstractSet<Entry<Attribute, Attribute>>() {

        @Override
        public Iterator<Entry<Attribute, Attribute>> iterator() {

            final Iterator<Attribute> iterator = attributes.iterator();

            return new Iterator<Entry<Attribute, Attribute>>() {

                @Override
                public boolean hasNext() {

                    return iterator.hasNext();
                }

                @Override
                public Entry<Attribute, Attribute> next() {

                    Attribute attribute = iterator.next();

                    return new SimpleImmutableEntry<>(attribute, attribute);
                }

                @Override
                public void remove() {

                    throw new UnsupportedOperationException("Read-only iterator.");
                }
            };
        }

        @Override
        public int size() {

            return attributes.size();
        }
    };
}

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From source file:de.tudarmstadt.ukp.dkpro.core.performance.PerformanceTestUtil.java

public static <T> Iterable<T> repeat(final T aObject, final int aCount) {
    return new Iterable<T>() {
        @Override/*from   ww  w . j a v a2s.c om*/
        public Iterator<T> iterator() {
            return new Iterator<T>() {
                private int i = 0;

                @Override
                public boolean hasNext() {
                    return i < aCount;
                }

                @Override
                public T next() {
                    i++;
                    return aObject;
                }

                @Override
                public void remove() {
                    throw new UnsupportedOperationException();
                }
            };
        }
    };
}

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From source file:MultiMap.java

public Set entrySet() {
    int size = 0;
    Iterator iterKeys = map.entrySet().iterator();
    while (iterKeys.hasNext()) {
        Map.Entry entry = (Map.Entry) iterKeys.next();
        Collection values = (Collection) entry.getValue();
        Iterator iterValues = values.iterator();
        while (iterValues.hasNext()) {
            size++;/*from  w ww  .  ja  v a 2 s . c o m*/
            iterValues.next();
        }
    }

    final int finalSize = size;

    final Iterator entries = map.entrySet().iterator();

    return new AbstractSet() {
        int pos = 0;
        Map.Entry entry;
        Iterator values;

        public Iterator iterator() {
            return new Iterator() {
                public void remove() {
                    throw new UnsupportedOperationException();
                }

                public boolean hasNext() {
                    return pos != finalSize;
                }

                public Object next() {
                    while (true) {
                        if (entry == null) {
                            entry = (Map.Entry) entries.next();
                            values = ((Collection) entry.getValue()).iterator();
                        }
                        Object key = entry.getKey();
                        if (values.hasNext()) {
                            Object value = values.next();
                            pos++;
                            return new Entry(key, value);
                        } else {
                            entry = null;
                        }
                    }
                }
            };
        }

        public int size() {
            return finalSize;
        }
    };
}

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From source file:de.codesourcery.jasm16.ast.ASTUtils.java

public static Iterator<ASTNode> createDepthFirst(ASTNode node) {
    final Stack<ASTNode> stack = new Stack<ASTNode>();
    if (node != null) {
        stack.push(node);//from   w  w  w .j a va2  s  .co m
    }
    return new Iterator<ASTNode>() {

        @Override
        public boolean hasNext() {
            return !stack.isEmpty();
        }

        @Override
        public ASTNode next() {
            ASTNode n = stack.peek();
            for (ASTNode child : n.getChildren()) {
                stack.push(child);
            }
            return stack.pop();
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("Not implemented");
        }
    };
}

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