arangodb/Documentation/Books/Drivers/java-reference-cursor.md

layout	description
default	ArangoCursor instances provide an abstraction over the HTTP API's limitations

Cursor API

ArangoCursor instances provide an abstraction over the HTTP API's limitations. Unless a method explicitly exhausts the cursor, the driver will only fetch as many batches from the server as necessary. Like the server-side cursors, ArangoCursor instances are incrementally depleted as they are read from.

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query(
  "FOR x IN 1..5 RETURN x", Integer.class
);
// query result list: [1, 2, 3, 4, 5]
Integer value = cursor.next();
assertThat(value, is(1));
// remaining result list: [2, 3, 4, 5]

ArangoCursor.hasNext

ArangoCursor.hasNext() : boolean

Returns true if the cursor has more elements in its current batch of results or the cursor on the server has more batches.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
boolean hasNext = cursor.hasNext();

ArangoCursor.next

ArangoCursor.next() : T

Returns the next element of the query result. If the current element is the last element of the batch and the cursor on the server provides more batches, the next batch is fetched from the server.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
Integer value = cursor.next();
assertThat(value, is(1));

ArangoCursor.first

ArangoCursor.first() : T

Returns the first element or {@code null} if no element exists.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("RETURN 1", Integer.class)
Integer value = cursor.first();
assertThat(value, is(1));

ArangoCursor.foreach

ArangoCursor.foreach(Consumer<? super T> action) : void

Performs the given action for each element of the ArangoIterable

Arguments

• action: Consumer<? super T>

  A action to perform on the elements

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
cursor.foreach(e -> {
  // remaining results: [1, 2, 3, 4, 5]
});

ArangoCursor.map

ArangoCursor.map(Function<? super T, ? extends R> mapper) : ArangoIterable<R>

Returns a ArangoIterable consisting of the results of applying the given function to the elements of this ArangoIterable.

Arguments

• mapper: Function<? super T, ? extends R>

  A function to apply to each element

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
cursor.map(e -> e * 10).foreach(e -> {
  // remaining results: [10, 20, 30, 40, 50]
});

ArangoCursor.filter

ArangoCursor.filter(Predicate<? super T> predicate) : ArangoIterable<T>

Arguments

• predicate: Predicate<? super T>

  A predicate to apply to each element to determine if it should be included

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
cursor.filter(e -> e < 4).foreach(e -> {
  // remaining results: [1, 2, 3]
});

ArangoCursor.anyMatch

ArangoCursor.anyMatch(Predicate<? super T> predicate) : boolean

Returns whether any elements of this ArangoIterable match the provided predicate.

Arguments

• predicate: Predicate<? super T>

  A predicate to apply to elements of this {@code ArangoIterable}

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
boolean match = cursor.anyMatch(e -> e == 3);
assertThat(match, is(true));

ArangoCursor.allMatch

ArangoCursor.anyMatch(Predicate<? super T> predicate) : boolean

Returns whether all elements of this ArangoIterable match the provided predicate.

Arguments

• predicate: Predicate<? super T>

  A predicate to apply to elements of this {@code ArangoIterable}

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
boolean match = cursor.allMatch(e -> e <= 5);
assertThat(match, is(true));

ArangoCursor.noneMatch

ArangoCursor.noneMatch(Predicate<? super T> predicate) : boolean

Returns whether no elements of this ArangoIterable match the provided predicate.

Arguments

• predicate: Predicate<? super T>

  A predicate to apply to elements of this {@code ArangoIterable}

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
boolean match = cursor.noneMatch(e -> e > 5);
assertThat(match, is(true));

ArangoCursor.collectInto

ArangoCursor.collectInto(R target) : R

Arguments

Iterates over all elements of this {@code ArangoIterable} and adds each to the given target.

• target: R <R extends Collection<? super T>>

  The collection to insert into

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
Collection<Integer> list = cursor.collectInto(new ArrayList());
// -- or --
Collection<Integer> set = cursor.collectInto(new HashSet());

ArangoCursor.iterator

ArangoCursor.iterator() : Iterator<T>

Returns an iterator over elements of the query result.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
Iterator<Integer> iterator = cursor.iterator();

ArangoCursor.asListRemaining

ArangoCursor.asListRemaining() : List<T>

Returns the remaining results as a List.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
Collection<Integer> list = cursor.asListRemaining();

ArangoCursor.getCount

ArangoCursor.getCount() : Integer

Returns the total number of result documents available (only available if the query was executed with the count attribute set)

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", new AqlQueryOptions().count(true), Integer.class)
Integer count = cursor.getCount();
assertThat(count, is(5));

ArangoCursor.count

ArangoCursor.count() : long

Returns the count of elements of this ArangoIterable.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
long count = cursor.filter(e -> e < 4).count();
// remaining results: [1, 2, 3]
assertThat(count, is(3L));

ArangoCursor.getStats

ArangoCursor.getStats() : Stats

Returns extra information about the query result. For data-modification queries, the stats will contain the number of modified documents and the number of documents that could not be modified due to an error (if ignoreErrors query option is specified).

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
Stats stats = cursor.getStats();

ArangoCursor.getWarnings

ArangoCursor.getWarnings() : Collection<Warning>

Returns warnings which the query could have been produced.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
Collection<Warning> warnings = cursor.getWarnings();

ArangoCursor.isCached

ArangoCursor.isCached() : boolean

Indicating whether the query result was served from the query cache or not.

Examples

ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");

ArangoCursor<Integer> cursor = db.query("FOR x IN 1..5 RETURN x", Integer.class)
boolean cached = cursor.isCached();