PagingPredicate (Hazelcast Root 3.12.9 API)

java.lang.Object
- com.hazelcast.query.PagingPredicate<K,V>

Type Parameters:: K -; V -

All Implemented Interfaces:: DataSerializable, IdentifiedDataSerializable, IndexAwarePredicate<K,V>, Predicate<K,V>, VisitablePredicate, Serializable

public class PagingPredicate<K,V>
extends Object
implements IndexAwarePredicate<K,V>, VisitablePredicate, IdentifiedDataSerializable

This class is a special Predicate which helps to get a page-by-page result of a query. It can be constructed with a page-size, an inner predicate for filtering, and a comparator for sorting. This class is not thread-safe and stateless. To be able to reuse for another query, one should call reset()
Here is an example usage.

 Predicate lessEqualThanFour = Predicates.lessEqual("this", 4);

 // We are constructing our paging predicate with a predicate and page size. In this case query results fetched two
 by two.
 PagingPredicate predicate = new PagingPredicate(lessEqualThanFour, 2);

 // we are initializing our map with integers from 0 to 10 as keys and values.
 IMap map = hazelcastInstance.getMap(...);
 for (int i = 0; i < 10; i++) {
 map.put(i, i);
 }

 // invoking the query
 Collection values = map.values(predicate);
 System.out.println("values = " + values) // will print 'values = [0, 1]'
 predicate.nextPage(); // we are setting up paging predicate to fetch next page in the next call.
 values = map.values(predicate);
 System.out.println("values = " + values);// will print 'values = [2, 3]'
 Entry anchor = predicate.getAnchor();
 System.out.println("anchor -> " + anchor); // will print 'anchor -> 1=1',  since the anchor is the last entry of
 the previous page.
 predicate.previousPage(); // we are setting up paging predicate to fetch previous page in the next call
 values = map.values(predicate);
 System.out.println("values = " + values) // will print 'values = [0, 1]'

See Also:: Serialized Form

Constructor Summary

Constructors
Constructor and Description
`PagingPredicate()` Used for serialization internally
`PagingPredicate(Comparator<Map.Entry<K,V>> comparator, int pageSize)` Construct with a comparator and pageSize results will not be filtered results will be ordered via comparator throws `IllegalArgumentException` if pageSize is not greater than 0
`PagingPredicate(int pageSize)` Construct with a pageSize results will not be filtered results will be natural ordered throws `IllegalArgumentException` if pageSize is not greater than 0
`PagingPredicate(Predicate<K,V> predicate, Comparator<Map.Entry<K,V>> comparator, int pageSize)` Construct with an inner predicate, comparator and pageSize results will be filtered via inner predicate results will be ordered via comparator throws `IllegalArgumentException` if pageSize is not greater than 0 throws `IllegalArgumentException` if inner predicate is also `PagingPredicate`
`PagingPredicate(Predicate predicate, int pageSize)` Construct with an inner predicate and pageSize results will be filtered via inner predicate results will be natural ordered throws `IllegalArgumentException` if pageSize is not greater than 0 throws `IllegalArgumentException` if inner predicate is also `PagingPredicate`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Predicate`	`accept(Visitor visitor, Indexes indexes)` Accept visitor.
`boolean`	`apply(Map.Entry mapEntry)` Used for delegating filtering to inner predicate.
`Set<QueryableEntry<K,V>>`	`filter(QueryContext queryContext)` Used if inner predicate is instanceof `IndexAwarePredicate` for filtering.
`Map.Entry<K,V>`	`getAnchor()` Retrieve the anchor object which is the last value object on the previous page.
`Comparator<Map.Entry<K,V>>`	`getComparator()`
`int`	`getFactoryId()` Returns DataSerializableFactory factory ID for this class.
`int`	`getId()` Returns type identifier for this class.
`IterationType`	`getIterationType()`
`int`	`getPage()`
`int`	`getPageSize()`
`Predicate<K,V>`	`getPredicate()`
`boolean`	`isIndexed(QueryContext queryContext)` Used if inner predicate is instanceof `IndexAwarePredicate` for checking if indexed.
`void`	`nextPage()` sets the page value to next page
`void`	`previousPage()` sets the page value to previous page
`void`	`readData(ObjectDataInput in)` Reads fields from the input stream
`void`	`reset()` resets for reuse
`void`	`setIterationType(IterationType iterationType)`
`void`	`setPage(int page)`
`void`	`writeData(ObjectDataOutput out)` Writes object fields to output stream

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

- Constructor Detail
  - PagingPredicate
```
public PagingPredicate()
```
    Used for serialization internally
  - PagingPredicate
```
public PagingPredicate(int pageSize)
```
    Construct with a pageSize results will not be filtered results will be natural ordered throws IllegalArgumentException if pageSize is not greater than 0
    
    Parameters:
    
    pageSize - page size
  - PagingPredicate
```
public PagingPredicate(Predicate predicate,
                       int pageSize)
```
    Construct with an inner predicate and pageSize results will be filtered via inner predicate results will be natural ordered throws IllegalArgumentException if pageSize is not greater than 0 throws IllegalArgumentException if inner predicate is also PagingPredicate
    
    Parameters:
    
    predicate - the inner predicate through which results will be filtered
    
    pageSize - the page size
  - PagingPredicate
```
public PagingPredicate(Comparator<Map.Entry<K,V>> comparator,
                       int pageSize)
```
    Construct with a comparator and pageSize results will not be filtered results will be ordered via comparator throws IllegalArgumentException if pageSize is not greater than 0
    
    Parameters:
    
    comparator - the comparator through which results will be ordered
    
    pageSize - the page size
  - PagingPredicate
```
public PagingPredicate(Predicate<K,V> predicate,
                       Comparator<Map.Entry<K,V>> comparator,
                       int pageSize)
```
    Construct with an inner predicate, comparator and pageSize results will be filtered via inner predicate results will be ordered via comparator throws IllegalArgumentException if pageSize is not greater than 0 throws IllegalArgumentException if inner predicate is also PagingPredicate
    
    Parameters:
    
    predicate - the inner predicate through which results will be filtered
    
    comparator - the comparator through which results will be ordered
    
    pageSize - the page size
- Method Detail
  - accept
```
public Predicate accept(Visitor visitor,
                        Indexes indexes)
```
    Description copied from interface: VisitablePredicate
    
    Accept visitor. Predicate can either return it's own instance if no modification was done as a result of the visit. In the case there is a change needed then the predicate has to return changed copy of itself. Predicates has to be treated as immutable for optimization purposes.
    
    Specified by:
    
    accept in interface VisitablePredicate
    
    Parameters:
    
    visitor - visitor to accept
    
    indexes - indexes
    
    Returns:
    
    itself or its changed copy
  - filter
```
public Set<QueryableEntry<K,V>> filter(QueryContext queryContext)
```
    Used if inner predicate is instanceof IndexAwarePredicate for filtering.
    
    Specified by:
    
    filter in interface IndexAwarePredicate<K,V>
    
    Parameters:
    
    queryContext -
    
    Returns:
  - isIndexed
```
public boolean isIndexed(QueryContext queryContext)
```
    Used if inner predicate is instanceof IndexAwarePredicate for checking if indexed.
    
    Specified by:
    
    isIndexed in interface IndexAwarePredicate<K,V>
    
    Parameters:
    
    queryContext -
    
    Returns:
  - apply
```
public boolean apply(Map.Entry mapEntry)
```
    Used for delegating filtering to inner predicate.
    
    Specified by:
    
    apply in interface Predicate<K,V>
    
    Parameters:
    
    mapEntry -
    
    Returns:
  - reset
```
public void reset()
```
    resets for reuse
  - nextPage
```
public void nextPage()
```
    sets the page value to next page
  - previousPage
```
public void previousPage()
```
    sets the page value to previous page
  - getIterationType
```
public IterationType getIterationType()
```
  - setIterationType
```
public void setIterationType(IterationType iterationType)
```
  - getPage
```
public int getPage()
```
  - setPage
```
public void setPage(int page)
```
  - getPageSize
```
public int getPageSize()
```
  - getPredicate
```
public Predicate<K,V> getPredicate()
```
  - getComparator
```
public Comparator<Map.Entry<K,V>> getComparator()
```
  - getAnchor
```
public Map.Entry<K,V> getAnchor()
```
    Retrieve the anchor object which is the last value object on the previous page.
    Note: This method will return `null` on the first page of the query result.
    
    Returns:
    
    Map.Entry the anchor object which is the last value object on the previous page
  - writeData
```
public void writeData(ObjectDataOutput out)
               throws IOException
```
    Description copied from interface: DataSerializable
    
    Writes object fields to output stream
    
    Specified by:
    
    writeData in interface DataSerializable
    
    Parameters:
    
    out - output
    
    Throws:
    
    IOException - if an I/O error occurs. In particular, an IOException may be thrown if the output stream has been closed.
  - readData
```
public void readData(ObjectDataInput in)
              throws IOException
```
    Description copied from interface: DataSerializable
    
    Reads fields from the input stream
    
    Specified by:
    
    readData in interface DataSerializable
    
    Parameters:
    
    in - input
    
    Throws:
    
    IOException - if an I/O error occurs. In particular, an IOException may be thrown if the input stream has been closed.
  - getFactoryId
```
public int getFactoryId()
```
    Description copied from interface: IdentifiedDataSerializable
    
    Returns DataSerializableFactory factory ID for this class.
    
    Specified by:
    
    getFactoryId in interface IdentifiedDataSerializable
    
    Returns:
    
    factory ID
  - getId
```
public int getId()
```
    Description copied from interface: IdentifiedDataSerializable
    
    Returns type identifier for this class. It should be unique per DataSerializableFactory.
    
    Specified by:
    
    getId in interface IdentifiedDataSerializable
    
    Returns:
    
    type ID

Class PagingPredicate<K,V>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

PagingPredicate

PagingPredicate

PagingPredicate

PagingPredicate

PagingPredicate

Method Detail

accept

filter

isIndexed

apply

reset

nextPage

previousPage

getIterationType

setIterationType

getPage

setPage

getPageSize

getPredicate

getComparator

getAnchor

writeData

readData

getFactoryId

getId