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:com.datumbox.framework.common.dataobjects.Dataframe.java

/**
 * Returns a read-only Iterable on the keys of the Dataframe.
 * //from   ww  w  .jav a 2  s  .  co m
 * @return 
 */
public Iterable<Integer> index() {
    return () -> new Iterator<Integer>() {
        private final Iterator<Integer> it = records.keySet().iterator();

        /** {@inheritDoc} */
        @Override
        public boolean hasNext() {
            return it.hasNext();
        }

        /** {@inheritDoc} */
        @Override
        public Integer next() {
            return it.next();
        }

        /** {@inheritDoc} */
        @Override
        public void remove() {
            throw new UnsupportedOperationException(
                    "This is a read-only iterator, remove operation is not supported.");
        }
    };
}

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From source file:gobblin.couchbase.writer.CouchbaseWriterTest.java

@Test
public void testMultiTupleDocumentWriteWithAsyncWriter()
        throws IOException, DataConversionException, ExecutionException, InterruptedException {
    final Schema dataRecordSchema = SchemaBuilder.record("Data").fields().name("data").type().bytesType()
            .noDefault().name("flags").type().intType().noDefault().endRecord();

    final Schema schema = SchemaBuilder.record("TestRecord").fields().name("key").type().stringType()
            .noDefault().name("data").type(dataRecordSchema).noDefault().endRecord();

    final int numRecords = 1000;

    Iterator<GenericRecord> recordIterator = new Iterator<GenericRecord>() {
        private int currentIndex;

        @Override//from www  . ja v  a  2 s.  c o  m
        public void remove() {
        }

        @Override
        public boolean hasNext() {
            return (currentIndex < numRecords);
        }

        @Override
        public GenericRecord next() {
            GenericData.Record testRecord = new GenericData.Record(schema);

            String testContent = "hello world" + currentIndex;
            GenericData.Record dataRecord = new GenericData.Record(dataRecordSchema);
            dataRecord.put("data", ByteBuffer.wrap(testContent.getBytes(Charset.forName("UTF-8"))));
            dataRecord.put("flags", 0);

            testRecord.put("key", "hello" + currentIndex);
            testRecord.put("data", dataRecord);
            currentIndex++;
            return testRecord;
        }
    };
    writeRecordsWithAsyncWriter(new TupleDocumentIterator(recordIterator));
}

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From source file:edu.umd.cfar.lamp.viper.util.StringHelp.java

/**
 * Decodes a comma seperated list of quoted strings.
 * Quotes are encoded by doubling them./*from   www  .j  a v  a  2 s.  c o  m*/
 * @param list
 * @return
 */
public static Iterator decodeDoublequotedList(final String list) {
    return new Iterator() {
        String next = null;
        int cursor = 0;

        private void cacheNext() {
            StringBuffer sb = new StringBuffer();
            char next = list.charAt(cursor);
            if (next == '"') {
                // in a quoted thing
                while (cursor < list.length()) {
                    next = list.charAt(cursor);
                    if (next == '"') {
                        cursor++;
                        next = list.charAt(cursor);
                        if (next == '"') {
                            sb.append('"');
                            cursor++;
                            continue;
                        } else {
                            cursor += 2;
                            break;
                        }
                    }
                    sb.append(next);
                    cursor++;
                }
            } else {
                // in a bare string
                while (cursor < list.length()) {
                    next = list.charAt(cursor);
                    if (next == ',') {
                        cursor++;
                        break;
                    }
                    sb.append(next);
                    cursor++;
                }
            }
            this.next = sb.toString();
        }

        public boolean hasNext() {
            if (next == null) {
                cacheNext();
            }
            return cursor < list.length();
        }

        public Object next() {
            if (!hasNext()) {
                throw new IndexOutOfBoundsException();
            }
            String r = next;
            next = null;
            return r;
        }

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

---

From source file:org.briljantframework.array.AbstractLongArray.java

@Override
public Iterator<Long> iterator() {
    return new Iterator<Long>() {
        private int index = 0;

        @Override//from ww w . java2  s  .c om
        public boolean hasNext() {
            return index < size();
        }

        @Override
        public Long next() {
            return get(index++);
        }
    };
}

---

From source file:com.github.jsonj.JsonArray.java

/**
 * Convenience method to prevent casting JsonElement to Long when iterating in the common case that you have
 * an array of longs.//  ww w  .ja v  a 2s .co  m
 *
 * @return iterable that iterates over Longs instead of JsonElements.
 */
public Iterable<Integer> ints() {
    final JsonArray parent = this;
    return new Iterable<Integer>() {

        @Override
        public Iterator<Integer> iterator() {
            final Iterator<JsonElement> iterator = parent.iterator();
            return new Iterator<Integer>() {

                @Override
                public boolean hasNext() {
                    return iterator.hasNext();
                }

                @Override
                public Integer next() {
                    return iterator.next().asInt();
                }

                @Override
                public void remove() {
                    iterator.remove();
                }
            };
        }
    };
}

---

From source file:com.datumbox.framework.common.dataobjects.Dataframe.java

/**
 * Returns a read-only Iterable on the values of the Dataframe.
 * /*w w  w.j a  v a2 s.c om*/
 * @return 
 */
public Iterable<Record> values() {
    return () -> new Iterator<Record>() {
        private final Iterator<Record> it = records.values().iterator();

        /** {@inheritDoc} */
        @Override
        public boolean hasNext() {
            return it.hasNext();
        }

        /** {@inheritDoc} */
        @Override
        public Record next() {
            return it.next();
        }

        /** {@inheritDoc} */
        @Override
        public void remove() {
            throw new UnsupportedOperationException(
                    "This is a read-only iterator, remove operation is not supported.");
        }
    };
}

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From source file:org.apache.lens.cube.parse.join.AutoJoinContext.java

/**
 * There can be multiple join paths between a dimension and the target. Set of all possible join clauses is the
 * cartesian product of join paths of all dimensions
 *///w w  w  .ja va 2 s . com
private Iterator<JoinClause> getJoinClausesForAllPaths(final StorageCandidate sc, final Set<Dimension> qDims,
        final CubeQueryContext cubeql) throws LensException {
    Map<Aliased<Dimension>, List<JoinPath>> allPaths;
    // if fact is passed only look at paths possible from fact to dims
    if (sc != null) {
        allPaths = pruneFactPaths(cubeql.getCube(), sc);
    } else {
        allPaths = new LinkedHashMap<>(this.allPaths);
    }
    // prune allPaths with qdims
    pruneAllPathsWithQueriedDims(allPaths, qDims);

    // Number of paths in each path set
    final int[] groupSizes = new int[allPaths.values().size()];
    // Total number of elements in the cartesian product
    int numSamples = 1;
    // All path sets
    final List<List<JoinPath>> pathSets = new ArrayList<>();
    // Dimension corresponding to the path sets
    final List<Aliased<Dimension>> dimensions = new ArrayList<>(groupSizes.length);

    int i = 0;
    for (Map.Entry<Aliased<Dimension>, List<JoinPath>> entry : allPaths.entrySet()) {
        dimensions.add(entry.getKey());
        List<JoinPath> group = entry.getValue();
        pathSets.add(group);
        groupSizes[i] = group.size();
        numSamples *= groupSizes[i];
        i++;
    }

    final int[] selection = new int[groupSizes.length];
    final int MAX_SAMPLE_COUNT = numSamples;

    // Return a lazy iterator over all possible join chains
    return new Iterator<JoinClause>() {
        int sample = 0;

        @Override
        public boolean hasNext() {
            return sample < MAX_SAMPLE_COUNT;
        }

        @Override
        public JoinClause next() {
            Map<Aliased<Dimension>, List<TableRelationship>> chain = new LinkedHashMap<>();
            //generate next permutation.
            for (int i = groupSizes.length - 1, base = sample; i >= 0; base /= groupSizes[i], i--) {
                selection[i] = base % groupSizes[i];
            }
            for (int i = 0; i < selection.length; i++) {
                int selectedPath = selection[i];
                List<TableRelationship> path = pathSets.get(i).get(selectedPath).getEdges();
                chain.put(dimensions.get(i), path);
            }

            Set<Dimension> dimsOnPath = getDimsOnPath(chain, qDims);

            sample++;
            // Cost of join = number of tables joined in the clause
            return new JoinClause(cubeql, chain, dimsOnPath);
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("Cannot remove elements!");
        }
    };
}

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From source file:org.apache.flink.runtime.executiongraph.ExecutionGraph.java

@Override
public Iterable<ExecutionJobVertex> getVerticesTopologically() {
    // we return a specific iterator that does not fail with concurrent modifications
    // the list is append only, so it is safe for that
    final int numElements = this.verticesInCreationOrder.size();

    return new Iterable<ExecutionJobVertex>() {
        @Override/*from  w  w w.  j  a  v  a2s  . c  o  m*/
        public Iterator<ExecutionJobVertex> iterator() {
            return new Iterator<ExecutionJobVertex>() {
                private int pos = 0;

                @Override
                public boolean hasNext() {
                    return pos < numElements;
                }

                @Override
                public ExecutionJobVertex next() {
                    if (hasNext()) {
                        return verticesInCreationOrder.get(pos++);
                    } else {
                        throw new NoSuchElementException();
                    }
                }

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

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From source file:org.lwes.ArrayEvent.java

@Override
public Iterator<FieldAccessor> iterator() {
    return new Iterator<FieldAccessor>() {
        private final ArrayEventFieldAccessor accessor = new ArrayEventFieldAccessor();

        public boolean hasNext() {
            return accessor.nextFieldIndex < length;
        }/*from   www  .j a  v  a2 s  . c o  m*/

        public FieldAccessor next() {
            accessor.advance();
            return accessor;
        }

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

---

From source file:org.openstreetmap.josm.tools.Utils.java

/**
 * Transforms the collection {@code c} into an unmodifiable collection and
 * applies the {@link Function} {@code f} on each element upon access.
 * @param <A> class of input collection
 * @param <B> class of transformed collection
 * @param c a collection// www.j  ava 2  s  .c  om
 * @param f a function that transforms objects of {@code A} to objects of {@code B}
 * @return the transformed unmodifiable collection
 */
public static <A, B> Collection<B> transform(final Collection<? extends A> c, final Function<A, B> f) {
    return new AbstractCollection<B>() {

        @Override
        public int size() {
            return c.size();
        }

        @Override
        public Iterator<B> iterator() {
            return new Iterator<B>() {

                private final Iterator<? extends A> it = c.iterator();

                @Override
                public boolean hasNext() {
                    return it.hasNext();
                }

                @Override
                public B next() {
                    return f.apply(it.next());
                }

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

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