Query (objectbox-java 2.9.1 API)

java.lang.Object
- io.objectbox.query.Query<T>

Type Parameters:

T - Entity class for which results are returned.

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable
```
public class Query<T>
extends java.lang.Object
implements java.io.Closeable
```
A repeatable Query returning the latest matching Objects.
Use find() or related methods to fetch the latest results from the BoxStore.
Use property(Property) to only return values or an aggregate of a single Property.
See the Queries documentation for details.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` If possible, try to close the query once you are done with it to reclaim resources immediately.
`long`	`count()` Returns the count of Objects matching the query.
`java.lang.String`	`describe()` For logging and testing, returns a string describing this query like "Query for entity Example with 4 conditions with properties prop1, prop2".
`java.lang.String`	`describeParameters()` For logging and testing, returns a string describing the conditions of this query like "(prop1 == A AND prop2 is null)".
`protected void`	`finalize()` Explicitly call `close()` instead to avoid expensive finalization.
`java.util.List<T>`	`find()` Find all Objects matching the query.
`java.util.List<T>`	`find(long offset, long limit)` Find all Objects matching the query, skipping the first offset results and returning at most limit results.
`T`	`findFirst()` Find the first Object matching the query.
`long[]`	`findIds()` Very efficient way to get just the IDs without creating any objects.
`long[]`	`findIds(long offset, long limit)` Like `findIds()` but with a offset/limit param, e.g.
`LazyList<T>`	`findLazy()` Like `findIds()`, but wraps the Object IDs in an unmodifiable `LazyList` so Objects can be retrieved on demand.
`LazyList<T>`	`findLazyCached()` Like `findIds()`, but wraps the Object IDs in an unmodifiable, caching `LazyList` so Objects can be retrieved on demand.
`T`	`findUnique()` Find the unique Object matching the query.
`void`	`forEach(QueryConsumer<T> consumer)` Emits query results one by one to the given consumer (synchronously).
`PropertyQuery`	`property(Property<T> property)` Creates a `PropertyQuery` for the given property.
`void`	`publish()` Publishes the current data to all subscribed @`DataObserver`s.
`long`	`remove()` Removes (deletes) all Objects matching the query
`Query<T>`	`setParameter(Property<?> property, boolean value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(Property<?> property, byte[] value)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameter(Property<?> property, java.util.Date value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(Property<?> property, double value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(Property<?> property, long value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(Property<?> property, java.lang.String value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(java.lang.String alias, boolean value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(java.lang.String alias, byte[] value)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameter(java.lang.String alias, java.util.Date value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(java.lang.String alias, double value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(java.lang.String alias, long value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameter(java.lang.String alias, java.lang.String value)` Sets a parameter previously given to the `QueryBuilder` to a new value.
`Query<T>`	`setParameters(Property<?> property, double value1, double value2)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(Property<?> property, int[] values)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(Property<?> property, long[] values)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(Property<?> property, long value1, long value2)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(Property<?> property, java.lang.String[] values)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(java.lang.String alias, double value1, double value2)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(java.lang.String alias, int[] values)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(java.lang.String alias, long[] values)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(java.lang.String alias, long value1, long value2)` Sets a parameter previously given to the `QueryBuilder` to new values.
`Query<T>`	`setParameters(java.lang.String alias, java.lang.String[] values)` Sets a parameter previously given to the `QueryBuilder` to new values.
`SubscriptionBuilder<java.util.List<T>>`	`subscribe()` A `DataObserver` can be subscribed to data changes using the returned builder.
`SubscriptionBuilder<java.util.List<T>>`	`subscribe(DataSubscriptionList dataSubscriptionList)` Convenience for `subscribe()` with a subsequent call to `SubscriptionBuilder.dataSubscriptionList(DataSubscriptionList)`.

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - finalize
```
protected void finalize()
                 throws java.lang.Throwable
```
    Explicitly call close() instead to avoid expensive finalization.
    
    Overrides:
    
    finalize in class java.lang.Object
    
    Throws:
    
    java.lang.Throwable
  - close
```
public void close()
```
    If possible, try to close the query once you are done with it to reclaim resources immediately.
    
    Specified by:
    
    close in interface java.io.Closeable
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
  - findFirst
```
@Nullable
public T findFirst()
```
    Find the first Object matching the query.
  - findUnique
```
@Nullable
public T findUnique()
```
    Find the unique Object matching the query.
    
    Throws:
    
    NonUniqueResultException - if result was not unique
  - find
```
@Nonnull
public java.util.List<T> find()
```
    Find all Objects matching the query.
  - find
```
@Nonnull
public java.util.List<T> find(long offset,
                                       long limit)
```
    Find all Objects matching the query, skipping the first offset results and returning at most limit results. Use this for pagination.
  - findIds
```
@Nonnull
public long[] findIds()
```
    Very efficient way to get just the IDs without creating any objects. IDs can later be used to lookup objects (lookups by ID are also very efficient in ObjectBox).
    Note: a filter set with QueryBuilder.filter(QueryFilter) will be silently ignored!
  - findIds
```
@Nonnull
public long[] findIds(long offset,
                               long limit)
```
    Like findIds() but with a offset/limit param, e.g. for pagination.
    Note: a filter set with QueryBuilder.filter(QueryFilter) will be silently ignored!
  - findLazy
```
@Nonnull
public LazyList<T> findLazy()
```
    Like findIds(), but wraps the Object IDs in an unmodifiable LazyList so Objects can be retrieved on demand. The LazyList does not cache retrieved Objects, so only basic List operations like getting or iterating list items are supported. See LazyList for details.
  - findLazyCached
```
@Nonnull
public LazyList<T> findLazyCached()
```
    Like findIds(), but wraps the Object IDs in an unmodifiable, caching LazyList so Objects can be retrieved on demand. The LazyList caches retrieved Objects supporting almost all List operations, at the expense of used memory. See LazyList for details.
  - property
```
public PropertyQuery property(Property<T> property)
```
    Creates a PropertyQuery for the given property.
    A PropertyQuery uses the same conditions as this Query object, but returns only the value(s) of a single property (not an entity objects).
    
    Parameters:
    
    property - the property for which to return values
  - forEach
```
public void forEach(QueryConsumer<T> consumer)
```
    Emits query results one by one to the given consumer (synchronously). Once this method returns, the consumer will have received all result object). It "streams" each object from the database to the consumer, which is very memory efficient. Because this is run in a read transaction, the consumer gets a consistent view on the data. Like findLazy(), this method can be used for a high amount of data.
    Note: because the consumer is called within a read transaction it may not write to the database.
  - count
```
public long count()
```
    Returns the count of Objects matching the query.
  - setParameter
```
public Query<T> setParameter(Property<?> property,
                             java.lang.String value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
  - setParameter
```
public Query<T> setParameter(java.lang.String alias,
                             java.lang.String value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameter
```
public Query<T> setParameter(Property<?> property,
                             long value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
  - setParameter
```
public Query<T> setParameter(java.lang.String alias,
                             long value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameter
```
public Query<T> setParameter(Property<?> property,
                             double value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
  - setParameter
```
public Query<T> setParameter(java.lang.String alias,
                             double value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameter
```
public Query<T> setParameter(Property<?> property,
                             java.util.Date value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
    
    Throws:
    
    java.lang.NullPointerException - if given date is null
  - setParameter
```
public Query<T> setParameter(java.lang.String alias,
                             java.util.Date value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
    
    Throws:
    
    java.lang.NullPointerException - if given date is null
  - setParameter
```
public Query<T> setParameter(Property<?> property,
                             boolean value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
  - setParameter
```
public Query<T> setParameter(java.lang.String alias,
                             boolean value)
```
    Sets a parameter previously given to the QueryBuilder to a new value.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameters
```
public Query<T> setParameters(Property<?> property,
                              long value1,
                              long value2)
```
    Sets a parameter previously given to the QueryBuilder to new values.
  - setParameters
```
public Query<T> setParameters(java.lang.String alias,
                              long value1,
                              long value2)
```
    Sets a parameter previously given to the QueryBuilder to new values.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameters
```
public Query<T> setParameters(Property<?> property,
                              int[] values)
```
    Sets a parameter previously given to the QueryBuilder to new values.
  - setParameters
```
public Query<T> setParameters(java.lang.String alias,
                              int[] values)
```
    Sets a parameter previously given to the QueryBuilder to new values.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameters
```
public Query<T> setParameters(Property<?> property,
                              long[] values)
```
    Sets a parameter previously given to the QueryBuilder to new values.
  - setParameters
```
public Query<T> setParameters(java.lang.String alias,
                              long[] values)
```
    Sets a parameter previously given to the QueryBuilder to new values.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameters
```
public Query<T> setParameters(Property<?> property,
                              double value1,
                              double value2)
```
    Sets a parameter previously given to the QueryBuilder to new values.
  - setParameters
```
public Query<T> setParameters(java.lang.String alias,
                              double value1,
                              double value2)
```
    Sets a parameter previously given to the QueryBuilder to new values.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameters
```
public Query<T> setParameters(Property<?> property,
                              java.lang.String[] values)
```
    Sets a parameter previously given to the QueryBuilder to new values.
  - setParameters
```
public Query<T> setParameters(java.lang.String alias,
                              java.lang.String[] values)
```
    Sets a parameter previously given to the QueryBuilder to new values.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - setParameter
```
public Query<T> setParameter(Property<?> property,
                             byte[] value)
```
    Sets a parameter previously given to the QueryBuilder to new values.
  - setParameter
```
public Query<T> setParameter(java.lang.String alias,
                             byte[] value)
```
    Sets a parameter previously given to the QueryBuilder to new values.
    
    Parameters:
    
    alias - as defined using QueryBuilder.parameterAlias(String).
  - remove
```
public long remove()
```
    Removes (deletes) all Objects matching the query
    
    Returns:
    
    count of removed Objects
  - subscribe
```
public SubscriptionBuilder<java.util.List<T>> subscribe()
```
    A DataObserver can be subscribed to data changes using the returned builder. The observer is supplied via SubscriptionBuilder.observer(DataObserver) and will be notified once the query results have (potentially) changed.
    With subscribing, the observer will immediately get current query results. The query is run for the subscribing observer.
    Threading notes: Query observers are notified from a thread pooled. Observers may be notified in parallel. The notification order is the same as the subscription order, although this may not always be guaranteed in the future.
    Stale observers: you must hold on to the Query or DataSubscription objects to keep your DataObservers active. If this Query is not referenced anymore (along with its DataSubscriptions, which hold a reference to the Query internally), it may be GCed and observers may become stale (won't receive anymore data).
  - subscribe
```
public SubscriptionBuilder<java.util.List<T>> subscribe(DataSubscriptionList dataSubscriptionList)
```
    Convenience for subscribe() with a subsequent call to SubscriptionBuilder.dataSubscriptionList(DataSubscriptionList).
    
    Parameters:
    
    dataSubscriptionList - the resulting DataSubscription will be added to it
  - publish
```
public void publish()
```
    Publishes the current data to all subscribed @DataObservers. This is useful triggering observers when new parameters have been set. Note, that setParameter methods will NOT be propagated to observers.
  - describe
```
public java.lang.String describe()
```
    For logging and testing, returns a string describing this query like "Query for entity Example with 4 conditions with properties prop1, prop2".
    Note: the format of the returned string may change without notice.
  - describeParameters
```
public java.lang.String describeParameters()
```
    For logging and testing, returns a string describing the conditions of this query like "(prop1 == A AND prop2 is null)".
    Note: the format of the returned string may change without notice.

Class Query<T>

Method Summary

Methods inherited from class java.lang.Object

Method Detail

finalize

close

findFirst

findUnique

find

find

findIds

findIds

findLazy

findLazyCached

property

forEach

count

setParameter

setParameter

setParameter

setParameter

setParameter

setParameter

setParameter

setParameter

setParameter

setParameter

setParameters

setParameters

setParameters

setParameters

setParameters

setParameters

setParameters

setParameters

setParameters

setParameters

setParameter

setParameter

remove

subscribe

subscribe

publish

describe

describeParameters