JsonPaintTarget (vaadin-all 8.6.1 API)

java.lang.Object
- com.vaadin.server.JsonPaintTarget

All Implemented Interfaces:

PaintTarget, Serializable
```
public class JsonPaintTarget
extends Object
implements PaintTarget
```
User Interface Description Language Target. TODO document better: role of this class, UIDL format, attributes, variables, etc.

Since:

5.0

Author:

Vaadin Ltd.

See Also:

Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from interface com.vaadin.server.PaintTarget
  PaintTarget.PaintStatus

Constructor Summary

Constructors
Constructor and Description
`JsonPaintTarget(LegacyCommunicationManager manager, Writer outWriter, boolean cachingRequired)` Creates a new JsonPaintTarget.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addAttribute(String name, boolean value)` Adds a boolean attribute to component.
`void`	`addAttribute(String name, Component value)` Adds a Component type attribute.
`void`	`addAttribute(String name, double value)` Adds a double attribute to component.
`void`	`addAttribute(String name, float value)` Adds a float attribute to component.
`void`	`addAttribute(String name, int value)` Adds a integer attribute to component.
`void`	`addAttribute(String name, long value)` Adds a long attribute to component.
`void`	`addAttribute(String name, Map<?,?> value)` Adds a `Map` attribute to the component.
`void`	`addAttribute(String name, Object[] values)`
`void`	`addAttribute(String name, Resource value)` Adds a resource attribute to component.
`void`	`addAttribute(String name, String value)` Adds a string attribute to component.
`void`	`addCharacterData(String text)` Adds CDATA node to target UIDL-tree.
`void`	`addSection(String sectionTagName, String sectionData)` Prints the single text section.
`void`	`addText(String str)` Prints XML-escaped text.
`void`	`addUIDL(String xml)` Adds XML directly to UIDL.
`void`	`addUploadStreamVariable(VariableOwner owner, String name)` Adds a upload stream type variable.
`void`	`addVariable(VariableOwner owner, String name, boolean value)` Adds a boolean type variable.
`void`	`addVariable(VariableOwner owner, String name, Component value)` Adds a Component type variable.
`void`	`addVariable(VariableOwner owner, String name, double value)` Adds a double type variable.
`void`	`addVariable(VariableOwner owner, String name, float value)` Adds a float type variable.
`void`	`addVariable(VariableOwner owner, String name, int value)` Adds an int type variable.
`void`	`addVariable(VariableOwner owner, String name, long value)` Adds a long type variable.
`void`	`addVariable(VariableOwner owner, String name, StreamVariable value)` Adds details about `StreamVariable` to the UIDL stream.
`void`	`addVariable(VariableOwner owner, String name, String value)` Adds a string type variable.
`void`	`addVariable(VariableOwner owner, String name, String[] value)` Adds a string array type variable.
`void`	`addXMLSection(String sectionTagName, String sectionData, String namespace)` Adds XML section with namespace.
`void`	`close()` Closes the paint target.
`void`	`endPaintable(Component paintable)` Prints paintable element end tag.
`void`	`endTag(String tagName)` Prints the element end tag.
`static String`	`escapeJSON(String s)` Escapes the given string so it can safely be used as a JSON string.
`static String`	`escapeXML(String xml)` Substitutes the XML sensitive characters with predefined XML entities.
`String`	`getTag(ClientConnector clientConnector)`
`String`	`getUIDL()` Gets the UIDL already printed to stream.
`Collection<Class<? extends ClientConnector>>`	`getUsedClientConnectors()`
`Set<Object>`	`getUsedResources()`
`boolean`	`isFullRepaint()`
`PaintTarget.PaintStatus`	`startPaintable(Component connector, String tagName)` Prints element start tag of a paintable section.
`void`	`startTag(String tagName)` Prints element start tag.
`void`	`startTag(String tagName, boolean isChildNode)` Prints the element start tag.

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

- Constructor Detail
  - JsonPaintTarget
```
public JsonPaintTarget(LegacyCommunicationManager manager,
                       Writer outWriter,
                       boolean cachingRequired)
                throws PaintException
```
    Creates a new JsonPaintTarget.
    
    Parameters:
    
    manager -
    
    outWriter - A character-output stream.
    
    cachingRequired - true if this is not a full repaint, i.e. caches are to be used.
    
    Throws:
    
    PaintException - if the paint operation failed.
- Method Detail
  - startTag
```
public void startTag(String tagName)
              throws PaintException
```
    Description copied from interface: PaintTarget
    Prints element start tag.
```
 Todo:
 Checking of input values
 
```
    Specified by:
    
    startTag in interface PaintTarget
    
    Parameters:
    
    tagName - the name of the start tag.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - startTag
```
public void startTag(String tagName,
                     boolean isChildNode)
              throws PaintException
```
    Prints the element start tag.
```
   Todo:
    Checking of input values

 
```
    Parameters:
    
    tagName - the name of the start tag.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - endTag
```
public void endTag(String tagName)
            throws PaintException
```
    Prints the element end tag. If the parent tag is closed before every child tag is closed an PaintException is raised.
    
    Specified by:
    
    endTag in interface PaintTarget
    
    Parameters:
    
    tagName - the name of the end tag.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - escapeXML
```
public static String escapeXML(String xml)
```
    Substitutes the XML sensitive characters with predefined XML entities.
    
    Parameters:
    
    xml - the String to be substituted.
    
    Returns:
    
    A new string instance where all occurrences of XML sensitive characters are substituted with entities.
  - escapeJSON
```
public static String escapeJSON(String s)
```
    Escapes the given string so it can safely be used as a JSON string.
    
    Parameters:
    
    s - The string to escape
    
    Returns:
    
    Escaped version of the string
  - addText
```
public void addText(String str)
             throws PaintException
```
    Prints XML-escaped text.
    
    Specified by:
    
    addText in interface PaintTarget
    
    Parameters:
    
    str -
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         boolean value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a boolean attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Attribute name.
    
    value - the Attribute value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         Resource value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a resource attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Attribute name
    
    value - the Attribute value
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         int value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a integer attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Attribute name.
    
    value - the Attribute value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         long value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a long attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Attribute name.
    
    value - the Attribute value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         float value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a float attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Attribute name.
    
    value - the Attribute value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         double value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a double attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Attribute name.
    
    value - the Attribute value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         String value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a string attribute to component. Attributes must be added before any content is written.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the Boolean attribute name.
    
    value - the Boolean attribute value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addAttribute
```
public void addAttribute(String name,
                         Component value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a Component type attribute. On client side the value will be a terminal specific reference to corresponding component on client side implementation.
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Parameters:
    
    name - the name of the attribute
    
    value - the Component to be referenced on client side
    
    Throws:
    
    PaintException
  - addAttribute
```
public void addAttribute(String name,
                         Map<?,?> value)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a Map attribute to the component. Attributes must be added before any content is written. TODO: specify how the map is added
    
    Specified by:
    
    addAttribute in interface PaintTarget
    
    Throws:
    
    PaintException
  - addAttribute
```
public void addAttribute(String name,
                         Object[] values)
```
    Specified by:
    
    addAttribute in interface PaintTarget
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        String value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a string type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        Component value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a Component type variable. On client side the variable value will be a terminal specific reference to corresponding component on client side implementation. When updated from client side, terminal will map the client side component reference back to a corresponding server side reference.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes
    
    name - the name of the variable
    
    value - the initial value of the variable
    
    Throws:
    
    PaintException - if the paint oparation fails
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        int value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds an int type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        long value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a long type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        float value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a float type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        double value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a double type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        boolean value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a boolean type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        String[] value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds a string array type variable.
    
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    value - the Variable initial value.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addUploadStreamVariable
```
public void addUploadStreamVariable(VariableOwner owner,
                                    String name)
                             throws PaintException
```
    Adds a upload stream type variable. TODO not converted for JSON
    
    Specified by:
    
    addUploadStreamVariable in interface PaintTarget
    
    Parameters:
    
    owner - the Listener for variable changes.
    
    name - the Variable name.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addSection
```
public void addSection(String sectionTagName,
                       String sectionData)
                throws PaintException
```
    Prints the single text section. Prints full text section. The section data is escaped
    
    Specified by:
    
    addSection in interface PaintTarget
    
    Parameters:
    
    sectionTagName - the name of the tag.
    
    sectionData - the section data to be printed.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addUIDL
```
public void addUIDL(String xml)
             throws PaintException
```
    Adds XML directly to UIDL.
    
    Specified by:
    
    addUIDL in interface PaintTarget
    
    Parameters:
    
    xml - the Xml to be added.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addXMLSection
```
public void addXMLSection(String sectionTagName,
                          String sectionData,
                          String namespace)
                   throws PaintException
```
    Adds XML section with namespace.
    
    Specified by:
    
    addXMLSection in interface PaintTarget
    
    Parameters:
    
    sectionTagName - the name of the tag.
    
    sectionData - the section data.
    
    namespace - the namespace to be added.
    
    Throws:
    
    PaintException - if the paint operation failed.
    
    See Also:
    
    PaintTarget.addXMLSection(String, String, String)
  - getUIDL
```
public String getUIDL()
```
    Gets the UIDL already printed to stream. Paint target must be closed before the getUIDL can be called.
    
    Returns:
    
    the UIDL.
  - close
```
public void close()
           throws PaintException
```
    Closes the paint target. Paint target must be closed before the getUIDL can be called. Subsequent attempts to write to paint target. If the target was already closed, call to this function is ignored. will generate an exception.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - startPaintable
```
public PaintTarget.PaintStatus startPaintable(Component connector,
                                              String tagName)
                                       throws PaintException
```
    Description copied from interface: PaintTarget
    
    Prints element start tag of a paintable section. Starts a paintable section using the given tag. The PaintTarget may implement a caching scheme, that checks the paintable has actually changed or can a cached version be used instead. This method should call the startTag method.
    If the Component is found in cache and this function returns true it may omit the content and close the tag, in which case cached content should be used.
    
    This method may also add only a reference to the paintable and queue the paintable to be painted separately.
    
    Each paintable being painted should be closed by a matching PaintTarget.endPaintable(Component) regardless of the PaintTarget.PaintStatus returned.
    
    Specified by:
    
    startPaintable in interface PaintTarget
    
    Parameters:
    
    connector - the paintable to start.
    
    tagName - the name of the start tag.
    
    Returns:
    
    PaintTarget.PaintStatus - ready to paint or already cached on the client (also used for sub paintables that are painted later separately)
    
    Throws:
    
    PaintException - if the paint operation failed.
    
    See Also:
    
    PaintTarget.startTag(String)
  - endPaintable
```
public void endPaintable(Component paintable)
                  throws PaintException
```
    Description copied from interface: PaintTarget
    
    Prints paintable element end tag. Calls to PaintTarget.startPaintable(Component, String)should be matched by PaintTarget.endPaintable(Component). If the parent tag is closed before every child tag is closed a PaintException is raised.
    
    Specified by:
    
    endPaintable in interface PaintTarget
    
    Parameters:
    
    paintable - the paintable to close.
    
    Throws:
    
    PaintException - if the paint operation failed.
  - addCharacterData
```
public void addCharacterData(String text)
                      throws PaintException
```
    Description copied from interface: PaintTarget
    
    Adds CDATA node to target UIDL-tree.
    
    Specified by:
    
    addCharacterData in interface PaintTarget
    
    Parameters:
    
    text - the Character data to add
    
    Throws:
    
    PaintException - if the paint operation failed.
  - getUsedResources
```
public Set<Object> getUsedResources()
```
  - getTag
```
public String getTag(ClientConnector clientConnector)
```
    Specified by:
    
    getTag in interface PaintTarget
    
    Returns:
    
    the "tag" string used in communication to present given ClientConnector type. Terminal may define how to present the connector.
  - getUsedClientConnectors
```
public Collection<Class<? extends ClientConnector>> getUsedClientConnectors()
```
  - addVariable
```
public void addVariable(VariableOwner owner,
                        String name,
                        StreamVariable value)
                 throws PaintException
```
    Description copied from interface: PaintTarget
    Adds details about StreamVariable to the UIDL stream. E.g. in web terminals Receivers are typically rendered for the client side as URLs, where the client side implementation can do an http post request.
    The urls in UIDL message may use Vaadin specific protocol. Before actually using the urls on the client side, they should be passed via ApplicationConnection.translateVaadinUri(String).
    Note that in current terminal implementation StreamVariables are cleaned from the terminal only when:
    - a StreamVariable with same name replaces an old one
    - the variable owner is no more attached
    - the developer signals this by calling StreamVariable.StreamingStartEvent.disposeStreamVariable()
    Most commonly a component developer can just ignore this issue, but with strict memory requirements and lots of StreamVariables implementations that reserve a lot of memory this may be a critical issue.
    Specified by:
    
    addVariable in interface PaintTarget
    
    Parameters:
    
    owner - the ReceiverOwner that can track the progress of streaming to the given StreamVariable
    
    name - an identifying name for the StreamVariable
    
    value - the StreamVariable to paint
    
    Throws:
    
    PaintException - if the paint operation failed.
  - isFullRepaint
```
public boolean isFullRepaint()
```
    Specified by:
    
    isFullRepaint in interface PaintTarget
    
    Returns:
    
    true if a full repaint has been requested. E.g. refresh in a browser window or such.

Class JsonPaintTarget

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.server.PaintTarget

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

JsonPaintTarget

Method Detail

startTag

startTag

endTag

escapeXML

escapeJSON

addText

addAttribute

addAttribute

addAttribute

addAttribute

addAttribute

addAttribute

addAttribute

addAttribute

addAttribute

addAttribute

addVariable

addVariable

addVariable

addVariable

addVariable

addVariable

addVariable

addVariable

addUploadStreamVariable

addSection

addUIDL

addXMLSection

getUIDL

close

startPaintable

endPaintable

addCharacterData

getUsedResources

getTag

getUsedClientConnectors

addVariable

isFullRepaint