com.softwareag.mobile.runtime.toolkit.rest

Class JSONDatasource

java.lang.Object

com.softwareag.mobile.runtime.toolkit.util.Observable

com.softwareag.mobile.runtime.toolkit.delegates.AbstractListDatasource

com.softwareag.mobile.runtime.toolkit.rest.JSONDatasource

All Implemented Interfaces:

IDatasource, IListDatasource

public class JSONDatasource
extends AbstractListDatasource

A JSONDatasource provides a IListDatasource implementation to manage and represent a data model based on JSON data to be used in ListViews.

Version:

10.1.0.0000-0462

Constructor Summary

Constructors

Constructor and Description
JSONDatasource(java.lang.String jsonData, java.lang.String expression) Creates a new JSONDatasource with a String of JSON formatted data and a JPath expression referencing the root object within the JSON data structure.
JSONDatasource(java.lang.String jsonData, java.lang.String expression, java.lang.String filterExpression) Creates a new JSONDatasource using a String of JSON formatted data, a JPath expression to reference the root object within the JSON data structure and a JPath filterExpression an object must match.

Method Summary

Modifier and Type	Method and Description
DatasourceException	getException() Use this method to get the last exception that has been caught while reloading the datasource.
java.lang.Object	getExpressionValue(java.lang.String rootExpression) This method is used to retrieve an object from the data model using an expression. An expression can be any String an IDatasource implementation uses to reference an object.
java.lang.Object	getExpressionValue(java.lang.String relativeExpression, int index) This method is used to get the object from the data model using an expression that is relative to on object in the data model with the given row index. An expression can be any String an IDatasource implementation uses to reference an object.
JPath	getRootJPath() Get the JPath object representing the root expression.
java.lang.String	getRootPathExpression() Returns the expression used to identify the root object within the JSON data structure.
boolean	hasException() Use this method to check for exceptions that might have been caught while reloading the datasource.
void	init(org.json.me.JSONObject jsonObject) Initializes the data source with a JSONObject representing the JSON data structure..
void	init(java.lang.String jsonData) Initializes the data source with a JSON data structure as String.
boolean	isFilteredElement(java.lang.Object object) Returns true if the given object matches the filter for this datasource returned by IListDatasource.getFilterExpression().
boolean	matchesExpression(java.lang.String filterExpression, int elementIndex) Returns a boolean value indicating whether the passed filterExpression is applicable for the underlying element, represented by it's elementIndex.
void	reloadElements() Use to reload the objects managed by the datasource.
void	setExpressionValue(java.lang.String rootExpression, java.lang.Object value) This method is used to update an object in the data model. An expression can be any String an IDatasource implementation uses to reference an object.
void	setExpressionValue(java.lang.String relativeExpression, java.lang.Object value, int index) This method is used to set the object in the data model using an expression that is relative to on object in the data model with the given row index. An expression can be any String an IDatasource implementation uses to reference an object.
void	setRootPathExpression(java.lang.String rootPathExpression) Set a new expression to identify the root object within the JSON data structure.

Methods inherited from class com.softwareag.mobile.runtime.toolkit.delegates.AbstractListDatasource

addElement, addElementAtIndex, addElements, compare, getComparator, getElementAtIndex, getElements, getFilteredElements, getFilterExpression, getNumberOfElements, getSelectedElement, removeAllElements, removeElement, removeElementAtIndex, resort, setComparator, setElements, setFilterExpression, setSelectedElement

Methods inherited from class com.softwareag.mobile.runtime.toolkit.util.Observable

addObserver, deleteObserver, notifyObservers, notifyObservers

Methods inherited from class java.lang.Object

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

Constructor Detail

JSONDatasource

public JSONDatasource(java.lang.String jsonData,
                      java.lang.String expression)

Creates a new JSONDatasource with a String of JSON formatted data and a JPath expression referencing the root object within the JSON data structure. The root object will be used for all other expressions.

Parameters:

jsonData - the json data to be used to initialize the datasource.

expression - a JPath expression to set the root object for the datasource

JSONDatasource

public JSONDatasource(java.lang.String jsonData,
                      java.lang.String expression,
                      java.lang.String filterExpression)

Creates a new JSONDatasource using a String of JSON formatted data, a JPath expression to reference the root object within the JSON data structure and a JPath filterExpression an object must match. The root object will be used as base for all other expressions.

Parameters:

jsonData - the json data to be used to initialize the datasource.

expression - a JPath expression to set the root object for the datasource

filterExpression - a JPath filterExpression each object must match to be added to the datasource.

Method Detail

init

public void init(java.lang.String jsonData)

Initializes the data source with a JSON data structure as String.

Parameters:

jsonData - the JSON data to be used

init

public void init(org.json.me.JSONObject jsonObject)

Initializes the data source with a JSONObject representing the JSON data structure..

Parameters:

jsonObject - the JSONObject to be used to initialize the datasource.

reloadElements

public void reloadElements()

Description copied from interface: IListDatasource

Use to reload the objects managed by the datasource.

Specified by:

reloadElements in interface IListDatasource

Specified by:

reloadElements in class AbstractListDatasource

hasException

public boolean hasException()

Description copied from interface: IListDatasource

Use this method to check for exceptions that might have been caught while reloading the datasource.

Specified by:

hasException in interface IListDatasource

Overrides:

hasException in class AbstractListDatasource

Returns:

true if there was an exception when initializing the elements.

getException

public DatasourceException getException()

Description copied from interface: IListDatasource

Use this method to get the last exception that has been caught while reloading the datasource.

Specified by:

getException in interface IListDatasource

Overrides:

getException in class AbstractListDatasource

Returns:

the last exception.

getRootPathExpression

public java.lang.String getRootPathExpression()

Returns the expression used to identify the root object within the JSON data structure. Use JPath expressions and syntax.

Returns:

the expression representing the root object in the JSON data structure

setRootPathExpression

public void setRootPathExpression(java.lang.String rootPathExpression)

Set a new expression to identify the root object within the JSON data structure. If null, the expressions are evaluated on the entire data structue.

Parameters:

rootPathExpression - the new JPath root expression

getRootJPath

public JPath getRootJPath()

Get the JPath object representing the root expression. Use this object to get data from the JSON data structure.

Returns:

the JPath object representing the root object

isFilteredElement

public boolean isFilteredElement(java.lang.Object object)

Description copied from interface: IListDatasource

Returns true if the given object matches the filter for this datasource returned by IListDatasource.getFilterExpression(). You need to implement this method specifically for your datasource and the object types managed.

Specified by:

isFilteredElement in interface IListDatasource

Overrides:

isFilteredElement in class AbstractListDatasource

Parameters:

object - the object to test if it matches IListDatasource.getFilterExpression()

Returns:

true if the filter returned by IListDatasource.getFilterExpression() matches the object, false if it does not

getExpressionValue

public java.lang.Object getExpressionValue(java.lang.String rootExpression)
                                    throws java.lang.Exception

Description copied from interface: IDatasource

This method is used to retrieve an object from the data model using an expression.
An expression can be any String an IDatasource implementation uses to reference an object.

Parameters:

rootExpression - String that references an object in the data model

Returns:

the object for the given expression or null if there was no object

Throws:

java.lang.Exception - if an error occured evaluating the given expression

getExpressionValue

public java.lang.Object getExpressionValue(java.lang.String relativeExpression,
                                           int index)
                                    throws java.lang.Exception

Description copied from interface: IListDatasource

This method is used to get the object from the data model using an expression that is relative to on object in the data model with the given row index.
An expression can be any String an IDatasource implementation uses to reference an object.

index - the index of the object to be used to evaluate the given expression

Returns:

the object for the given expression or null if there was no object

Throws:

java.lang.Exception - if an error occured evaluating the given expression

setExpressionValue

public void setExpressionValue(java.lang.String rootExpression,
                               java.lang.Object value)
                        throws java.lang.Exception

Description copied from interface: IDatasource

This method is used to update an object in the data model.
An expression can be any String an IDatasource implementation uses to reference an object.

Parameters:

rootExpression - String that references an object in the data model

value - new object value for the given expression

Throws:

java.lang.Exception - if an error occured evaluating the given expression

setExpressionValue

public void setExpressionValue(java.lang.String relativeExpression,
                               java.lang.Object value,
                               int index)
                        throws java.lang.Exception

Description copied from interface: IListDatasource

This method is used to set the object in the data model using an expression that is relative to on object in the data model with the given row index.
An expression can be any String an IDatasource implementation uses to reference an object.

Parameters:

relativeExpression - String that references an object in the data model

value - the new value for the given expression

index - the index of the object to be used to evaluate the given expression

Throws:

java.lang.Exception - if an error occured evaluating the given expression

matchesExpression

public boolean matchesExpression(java.lang.String filterExpression,
                                 int elementIndex)

Description copied from interface: IListDatasource

Returns a boolean value indicating whether the passed filterExpression is applicable for the underlying element, represented by it's elementIndex.
Returns false if the passed elementIndex is out of range.

This method is used to determine the expression to template mapping used in ContentAdapter.

Parameters:

filterExpression - String that references an object in the data model

elementIndex - the index of the object to be used to evaluate the given expression