org.apache.geode.cache

Interface Document

All Known Subinterfaces:

JsonDocument, PdxInstance, WritablePdxInstance

public interface Document

Users can implement this interface on classes they store in GemFire. The GemFire OQL query engine will handle objects that implement this interface in order to access fields.

Field Summary

Fields

Modifier and Type	Field and Description
static Object	FIELD_NOT_FOUND This Object is returned from getAndCheckField(String) if the field does not exist.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object other) Returns true if the given object is equals to this Document.
default void	foreach(BiConsumer<String,Object> action) For each field in this document call action with the field's name and value.
default Object	getAndCheckField(String fieldName) Checks if the field exists and if it does returns its value.
Object	getField(String fieldName) Reads the named field and returns its value.
List<String>	getFieldNames() Return an unmodifiable list of the field names.
boolean	hasField(String fieldName) Checks if the named field exists and returns the result.
int	hashCode() Generates a hashCode based on all fields of this Document.

Field Detail

FIELD_NOT_FOUND

@Immutable
static final Object FIELD_NOT_FOUND

This Object is returned from getAndCheckField(String) if the field does not exist.

Method Detail

hasField

boolean hasField(String fieldName)

Checks if the named field exists and returns the result.

Parameters:

fieldName - the name of the field to check

Returns:

true if the named field exists; otherwise false

getFieldNames

List<String> getFieldNames()

Return an unmodifiable list of the field names.

Returns:

an unmodifiable list of the field names

getField

Object getField(String fieldName)

Reads the named field and returns its value. If the field does not exist null is returned.

A null result indicates that the field does not exist or that it exists and its value is currently null. The hasField method can be used to figure out which of these two cases is true.

Parameters:

fieldName - name of the field to read

Returns:

If this instance has the named field then the field's value is returned, otherwise null is returned.

Throws:

RuntimeException - if the field could not be deserialized

equals

boolean equals(Object other)

Returns true if the given object is equals to this Document.

Otherwise equality of two Documents is determined as follows:

1. Every field must be equal.

A field is equal if all the following are true:

1. The field name is equal.
2. The field value is equal.

A field's value may be deserialized to determine if it is equals.

Overrides:

equals in class Object

Parameters:

other - the other Document to compare to this.

Returns:

true if this instance is equal to other.

hashCode

int hashCode()

Generates a hashCode based on all fields of this Document.

Overrides:

hashCode in class Object

getAndCheckField

default Object getAndCheckField(String fieldName)

Checks if the field exists and if it does returns its value. If the field does not exist returns FIELD_NOT_FOUND. Otherwise, behaves the same as getField(String). Some implementations may provide an implementation of this which performs better than the default.

Parameters:

fieldName - name of the field to read

Returns:

If this instance has the named field then the field's possibly null value is returned, otherwise FIELD_NOT_FOUND is returned.

Throws:

RuntimeException - if the field could not be deserialized

foreach

default void foreach(BiConsumer<String,Object> action)

For each field in this document call action with the field's name and value. Some implementations may provide an implementation of this which performs better than the default.

Parameters:

action - called for each field in this document