Package io.objectbox.query

Class QueryBuilder<T>

java.lang.Object

io.objectbox.query.QueryBuilder<T>

Type Parameters:

T - Entity class for which the Query is built.

public class QueryBuilder<T>
extends Object

Builds a Query using conditions which can then be used to return a list of matching Objects.

A simple example:

 userBox.query()
     .equal(User_.firstName, "Joe", StringOrder.CASE_SENSITIVE)
     .order(User_.lastName)
     .build()
     .find()
 

To add a condition use the appropriate method, for example equal(Property, String, StringOrder) or isNull(Property). To order results use order(Property) and its related methods.

Use build() to create a Query object, which is used to actually get the results.

Note: by default Query returns full Objects. To return only values or an aggregate value for a single Property, use Query.property(Property).

See the Queries documentation for details.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	QueryBuilder.StringOrder

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CASE_SENSITIVE	Makes upper case letters (e.g.
static final int	DESCENDING	Reverts the order from ascending (default) to descending.
static final int	NULLS_LAST	null values will be put last.
static final int	NULLS_ZERO	null values should be treated equal to zero (scalars only).
static final int	UNSIGNED	For scalars only: changes the comparison to unsigned (default is signed).

Constructor Summary

Constructors

Constructor	Description
QueryBuilder(Box<T> box, long storeHandle, String entityName)

Method Summary

Modifier and Type	Method	Description
QueryBuilder<T>	and()	And AND changes how conditions are combined using a following OR.
QueryBuilder<T>	apply(QueryCondition<T> queryCondition)	Experimental.
<TARGET> QueryBuilder<TARGET>	backlink(RelationInfo<TARGET,?> relationInfo)	Creates a backlink (reversed link) to another entity, for which you also can describe conditions using the returned builder.
QueryBuilder<T>	between(Property<T> property, double value1, double value2)	Finds objects with property value between and including the first and second value.
QueryBuilder<T>	between(Property<T> property, long value1, long value2)	Finds objects with property value between and including the first and second value.
QueryBuilder<T>	between(Property<T> property, Date value1, Date value2)	Finds objects with property value between and including the first and second value.
Query<T>	build()	Builds the query and closes this QueryBuilder.
void	close()	Close this query builder and free used resources.
QueryBuilder<T>	contains(Property<T> property, String value, QueryBuilder.StringOrder order)	Creates an contains condition.
QueryBuilder<T>	containsElement(Property<T> property, String value, QueryBuilder.StringOrder order)	For a String array, list or String-key map property, matches if at least one element equals the given value.
QueryBuilder<T>	containsKeyValue(Property<T> property, String key, String value, QueryBuilder.StringOrder order)	For a String-key map property, matches if at least one key and value combination equals the given values.
QueryBuilder<T>	eager(int limit, RelationInfo relationInfo, RelationInfo... more)	Like eager(RelationInfo, RelationInfo[]), but limits eager loading to the given count.
QueryBuilder<T>	eager(RelationInfo relationInfo, RelationInfo... more)	Specifies relations that should be resolved eagerly.
QueryBuilder<T>	endsWith(Property<T> property, String value, QueryBuilder.StringOrder order)
QueryBuilder<T>	equal(Property<T> property, boolean value)
QueryBuilder<T>	equal(Property<T> property, byte[] value)
QueryBuilder<T>	equal(Property<T> property, double value, double tolerance)	Floating point equality is non-trivial; this is just a convenience for between(Property, double, double) with parameters(property, value - tolerance, value + tolerance).
QueryBuilder<T>	equal(Property<T> property, long value)
QueryBuilder<T>	equal(Property<T> property, String value, QueryBuilder.StringOrder order)	Creates an "equal ('=')" condition for this property.
QueryBuilder<T>	equal(Property<T> property, Date value)
QueryBuilder<T>	filter(QueryFilter<T> filter)	Sets a filter that executes on primary query results (returned from the db core) on a Java level.
protected void	finalize()	Typically build() is called on this which calls close() and avoids expensive finalization here.
QueryBuilder<T>	greater(Property<T> property, byte[] value)
QueryBuilder<T>	greater(Property<T> property, double value)
QueryBuilder<T>	greater(Property<T> property, long value)
QueryBuilder<T>	greater(Property<T> property, String value, QueryBuilder.StringOrder order)
QueryBuilder<T>	greater(Property<T> property, Date value)
QueryBuilder<T>	greaterOrEqual(Property<T> property, byte[] value)
QueryBuilder<T>	greaterOrEqual(Property<T> property, double value)
QueryBuilder<T>	greaterOrEqual(Property<T> property, long value)
QueryBuilder<T>	greaterOrEqual(Property<T> property, String value, QueryBuilder.StringOrder order)
QueryBuilder<T>	greaterOrEqual(Property<T> property, Date value)
QueryBuilder<T>	in(Property<T> property, int[] values)
QueryBuilder<T>	in(Property<T> property, long[] values)
QueryBuilder<T>	in(Property<T> property, String[] values, QueryBuilder.StringOrder order)
QueryBuilder<T>	isNull(Property<T> property)
QueryBuilder<T>	less(Property<T> property, byte[] value)
QueryBuilder<T>	less(Property<T> property, double value)
QueryBuilder<T>	less(Property<T> property, long value)
QueryBuilder<T>	less(Property<T> property, String value, QueryBuilder.StringOrder order)
QueryBuilder<T>	less(Property<T> property, Date value)
QueryBuilder<T>	lessOrEqual(Property<T> property, byte[] value)
QueryBuilder<T>	lessOrEqual(Property<T> property, double value)
QueryBuilder<T>	lessOrEqual(Property<T> property, long value)
QueryBuilder<T>	lessOrEqual(Property<T> property, String value, QueryBuilder.StringOrder order)
QueryBuilder<T>	lessOrEqual(Property<T> property, Date value)
<TARGET> QueryBuilder<TARGET>	link(RelationInfo<?,TARGET> relationInfo)	Creates a link to another entity, for which you also can describe conditions using the returned builder.
QueryBuilder<T>	notEqual(Property<T> property, boolean value)
QueryBuilder<T>	notEqual(Property<T> property, long value)
QueryBuilder<T>	notEqual(Property<T> property, String value, QueryBuilder.StringOrder order)	Creates a "not equal ('<>')" condition for this property.
QueryBuilder<T>	notEqual(Property<T> property, Date value)
QueryBuilder<T>	notIn(Property<T> property, int[] values)
QueryBuilder<T>	notIn(Property<T> property, long[] values)
QueryBuilder<T>	notNull(Property<T> property)
QueryBuilder<T>	or()	Combines the previous condition with the following condition with a logical OR.
QueryBuilder<T>	order(Property<T> property)	Specifies given property to be used for sorting.
QueryBuilder<T>	order(Property<T> property, int flags)	Defines the order with which the results are ordered (default: none).
QueryBuilder<T>	orderDesc(Property<T> property)	Specifies given property in descending order to be used for sorting.
QueryBuilder<T>	parameterAlias(String alias)	Assigns the given alias to the previous condition.
QueryBuilder<T>	relationCount(RelationInfo<T,?> relationInfo, int relationCount)
QueryBuilder<T>	sort(Comparator<T> comparator)
QueryBuilder<T>	startsWith(Property<T> property, String value, QueryBuilder.StringOrder order)

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DESCENDING

public static final int DESCENDING

Reverts the order from ascending (default) to descending.

See Also:

• Constant Field Values

CASE_SENSITIVE

public static final int CASE_SENSITIVE

Makes upper case letters (e.g. "Z") be sorted before lower case letters (e.g. "a"). If not specified, the default is case insensitive for ASCII characters.

See Also:

• Constant Field Values

NULLS_LAST

public static final int NULLS_LAST

null values will be put last. If not specified, by default null values will be put first.

See Also:

• Constant Field Values

NULLS_ZERO

public static final int NULLS_ZERO

null values should be treated equal to zero (scalars only).

See Also:

• Constant Field Values

UNSIGNED

public static final int UNSIGNED

For scalars only: changes the comparison to unsigned (default is signed).

See Also:

• Constant Field Values

Constructor Details

QueryBuilder

@Internal
public QueryBuilder(Box<T> box,
 long storeHandle,
 String entityName)

Method Details

finalize

protected void finalize()
                 throws Throwable

Typically build() is called on this which calls close() and avoids expensive finalization here.

If build() is not called, make sure to explicitly call close().

Overrides:

finalize in class Object

Throws:

Throwable

close

public void close()

Close this query builder and free used resources.

This is not required when calling build().

build

public Query<T> build()

Builds the query and closes this QueryBuilder.

apply

@Experimental
public QueryBuilder<T> apply(QueryCondition<T> queryCondition)

Experimental. This API might change or be removed in the future based on user feedback.

Applies the given query conditions and returns the builder for further customization, such as result order. Build the condition using the properties from your entity underscore classes.

An example with a nested OR condition:

 # Java
 builder.apply(User_.name.equal("Jane")
         .and(User_.age.less(12)
                 .or(User_.status.equal("child"))));

 # Kotlin
 builder.apply(User_.name.equal("Jane")
         and (User_.age.less(12)
         or User_.status.equal("child")))
 

Use Box.query(QueryCondition) as a shortcut for this method.

order

public QueryBuilder<T> order(Property<T> property)

Specifies given property to be used for sorting. Shorthand for order(Property, int) with flags equal to 0.

See Also:

• order(Property, int)
• orderDesc(Property)

orderDesc

public QueryBuilder<T> orderDesc(Property<T> property)

Specifies given property in descending order to be used for sorting. Shorthand for order(Property, int) with flags equal to DESCENDING.

See Also:

• order(Property, int)
• order(Property)

order

public QueryBuilder<T> order(Property<T> property,
 int flags)

Defines the order with which the results are ordered (default: none). You can chain multiple order conditions. The first applied order condition will be the most relevant. Order conditions applied afterwards are only relevant if the preceding ones resulted in value equality.

Example:

queryBuilder.order(Name).orderDesc(YearOfBirth);

Here, "Name" defines the primary sort order. The secondary sort order "YearOfBirth" is only used to compare entries with the same "Name" values.

Parameters:

property - the property defining the order

flags - Bit flags that can be combined using the binary OR operator (|). Available flags are DESCENDING, CASE_SENSITIVE, NULLS_LAST, NULLS_ZERO, and UNSIGNED.

See Also:

• order(Property)
• orderDesc(Property)

sort

public QueryBuilder<T> sort(Comparator<T> comparator)

parameterAlias

public QueryBuilder<T> parameterAlias(String alias)

Assigns the given alias to the previous condition.

Parameters:

alias - The string alias for use with setParameter(s) methods.

link

public <TARGET> QueryBuilder<TARGET> link(RelationInfo<?,TARGET> relationInfo)

Creates a link to another entity, for which you also can describe conditions using the returned builder.

Note: in relational databases you would use a "join" for this.

Type Parameters:

TARGET - The target entity. For parent/tree like relations, it can be the same type.

Parameters:

relationInfo - Relation meta info (generated)

Returns:

A builder to define query conditions at the target entity side.

backlink

public <TARGET> QueryBuilder<TARGET> backlink(RelationInfo<TARGET,?> relationInfo)

Creates a backlink (reversed link) to another entity, for which you also can describe conditions using the returned builder.

Note: only use this method over link(RelationInfo), if you did not define @Backlink in the entity already.

Note: in relational databases you would use a "join" for this.

Type Parameters:

TARGET - The target entity. For parent/tree like relations, it can be the same type.

Parameters:

relationInfo - Relation meta info (generated) of the original relation (reverse direction)

Returns:

A builder to define query conditions at the target entity side.

eager

public QueryBuilder<T> eager(RelationInfo relationInfo,
 RelationInfo... more)

Specifies relations that should be resolved eagerly. This prepares the given relation objects to be preloaded (cached) avoiding further get operations from the db. A common use case is prealoading all

Parameters:

relationInfo - The relation as found in the generated meta info class ("EntityName_") of class T.

more - Supply further relations to be eagerly loaded.

eager

public QueryBuilder<T> eager(int limit,
 RelationInfo relationInfo,
 @Nullable
 RelationInfo... more)

Like eager(RelationInfo, RelationInfo[]), but limits eager loading to the given count.

Parameters:

limit - Count of entities to be eager loaded.

relationInfo - The relation as found in the generated meta info class ("EntityName_") of class T.

more - Supply further relations to be eagerly loaded.

filter

public QueryBuilder<T> filter(QueryFilter<T> filter)

Sets a filter that executes on primary query results (returned from the db core) on a Java level. For efficiency reasons, you should always prefer primary criteria like equal(Property, long) if possible. A filter requires to instantiate full Java objects beforehand, which is less efficient.

The upside of filters is that they allow any complex operation including traversing object graphs, and that filtering is executed along with the query (preferably in a background thread). Use filtering wisely ;-).

Also note, that a filter may only be used along with Query.find() and Query.forEach(QueryConsumer) at this point. Other find methods will throw a exception and aggregate functions will silently ignore the filter.

or

public QueryBuilder<T> or()

Combines the previous condition with the following condition with a logical OR.

Example (querying t-shirts):

 queryBuilder.equal(color, "blue").or().less(price, 30).build() // color is blue OR price < 30
 

and

public QueryBuilder<T> and()

And AND changes how conditions are combined using a following OR. By default, all query conditions are already combined using AND. Do not use this method if all your query conditions must match (AND for all, this is the default).

However, this method change the precedence with other combinations such as or(). This is best explained by example.

Example (querying t-shirts):

 // Case (1): OR has precedence
 queryBuilder.equal(color, "blue").equal(size, "XL").or().less(price, 30).build()

 // Case (2): AND has precedence
 queryBuilder.equal(color, "blue").and().equal(size, "XL").or().less(price, 30).build()
 

Rule: Explicit AND / OR combination have precedence.

That's why (1) is evaluated like "must be blue and is either of size XL or costs less than 30", or more formally: blue AND (size XL OR price less than 30).

Rule: Conditions are applied from left to right (in the order they are called).

That's why in (2) the AND is evaluated before the OR. Thus, (2) evaluates to "either must be blue and of size XL, or costs less than 30", or, more formally: (blue AND size XL) OR price less than 30.

isNull

public QueryBuilder<T> isNull(Property<T> property)

notNull

public QueryBuilder<T> notNull(Property<T> property)

relationCount

public QueryBuilder<T> relationCount(RelationInfo<T,?> relationInfo,
 int relationCount)

equal

public QueryBuilder<T> equal(Property<T> property,
 long value)

notEqual

public QueryBuilder<T> notEqual(Property<T> property,
 long value)

less

public QueryBuilder<T> less(Property<T> property,
 long value)

lessOrEqual

public QueryBuilder<T> lessOrEqual(Property<T> property,
 long value)

greater

public QueryBuilder<T> greater(Property<T> property,
 long value)

greaterOrEqual

public QueryBuilder<T> greaterOrEqual(Property<T> property,
 long value)

between

public QueryBuilder<T> between(Property<T> property,
 long value1,
 long value2)

Finds objects with property value between and including the first and second value.

in

public QueryBuilder<T> in(Property<T> property,
 long[] values)

notIn

public QueryBuilder<T> notIn(Property<T> property,
 long[] values)

in

public QueryBuilder<T> in(Property<T> property,
 int[] values)

notIn

public QueryBuilder<T> notIn(Property<T> property,
 int[] values)

equal

public QueryBuilder<T> equal(Property<T> property,
 boolean value)

notEqual

public QueryBuilder<T> notEqual(Property<T> property,
 boolean value)

equal

public QueryBuilder<T> equal(Property<T> property,
 Date value)

Throws:

NullPointerException - if given value is null. Use isNull(Property) instead.

notEqual

public QueryBuilder<T> notEqual(Property<T> property,
 Date value)

Throws:

NullPointerException - if given value is null. Use isNull(Property) instead.

less

public QueryBuilder<T> less(Property<T> property,
 Date value)

Throws:

NullPointerException - if given value is null. Use isNull(Property) instead.

lessOrEqual

public QueryBuilder<T> lessOrEqual(Property<T> property,
 Date value)

Throws:

NullPointerException - if given value is null. Use isNull(Property) instead.

greater

public QueryBuilder<T> greater(Property<T> property,
 Date value)

Throws:

NullPointerException - if given value is null. Use isNull(Property) instead.

greaterOrEqual

public QueryBuilder<T> greaterOrEqual(Property<T> property,
 Date value)

Throws:

NullPointerException - if given value is null. Use isNull(Property) instead.

between

public QueryBuilder<T> between(Property<T> property,
 Date value1,
 Date value2)

Finds objects with property value between and including the first and second value.

Throws:

NullPointerException - if one of the given values is null.

equal

public QueryBuilder<T> equal(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

Creates an "equal ('=')" condition for this property.

notEqual

public QueryBuilder<T> notEqual(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

Creates a "not equal ('<>')" condition for this property.

contains

public QueryBuilder<T> contains(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

Creates an contains condition.

Note: for a String array property, use containsElement(io.objectbox.Property<T>, java.lang.String, io.objectbox.query.QueryBuilder.StringOrder) instead.

containsElement

public QueryBuilder<T> containsElement(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

For a String array, list or String-key map property, matches if at least one element equals the given value.

containsKeyValue

public QueryBuilder<T> containsKeyValue(Property<T> property,
 String key,
 String value,
 QueryBuilder.StringOrder order)

For a String-key map property, matches if at least one key and value combination equals the given values.

startsWith

public QueryBuilder<T> startsWith(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

endsWith

public QueryBuilder<T> endsWith(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

less

public QueryBuilder<T> less(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

lessOrEqual

public QueryBuilder<T> lessOrEqual(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

greater

public QueryBuilder<T> greater(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

greaterOrEqual

public QueryBuilder<T> greaterOrEqual(Property<T> property,
 String value,
 QueryBuilder.StringOrder order)

in

public QueryBuilder<T> in(Property<T> property,
 String[] values,
 QueryBuilder.StringOrder order)

equal

public QueryBuilder<T> equal(Property<T> property,
 double value,
 double tolerance)

Floating point equality is non-trivial; this is just a convenience for between(Property, double, double) with parameters(property, value - tolerance, value + tolerance). When using Query.setParameters(Property, double, double), consider that the params are the lower and upper bounds.

less

public QueryBuilder<T> less(Property<T> property,
 double value)

lessOrEqual

public QueryBuilder<T> lessOrEqual(Property<T> property,
 double value)

greater

public QueryBuilder<T> greater(Property<T> property,
 double value)

greaterOrEqual

public QueryBuilder<T> greaterOrEqual(Property<T> property,
 double value)

between

public QueryBuilder<T> between(Property<T> property,
 double value1,
 double value2)

Finds objects with property value between and including the first and second value.

equal

public QueryBuilder<T> equal(Property<T> property,
 byte[] value)

less

public QueryBuilder<T> less(Property<T> property,
 byte[] value)

lessOrEqual

public QueryBuilder<T> lessOrEqual(Property<T> property,
 byte[] value)

greater

public QueryBuilder<T> greater(Property<T> property,
 byte[] value)

greaterOrEqual

public QueryBuilder<T> greaterOrEqual(Property<T> property,
 byte[] value)