Package com.caplin.datasource.messaging.page

Interface PageMessage

All Superinterfaces:
Message
public interface PageMessage extends Message

An instance of PageMessage represents updates to a Page subject.

 

An object implementing this interface cannot be instantiated directly, but can be constructed using the MessageFactory that is available on the Publisher interface.

 

Each update applies to a region of the page that starts at a specific column and row.

 

If you call setContent(int, int, String) more than once, and the page regions specified in successive calls overlap, the updates are still held separately in the message; they are not merged together.

Note: After publishing a message, do not reuse the message (e.g. change the content, republish) as this can cause issues.

  • Method Details

    • setContent

      void setContent(int column, int row, String content)

      Updates the contents of the page at the specified location.

      Parameters:
      column - The column at which the content is to be updated. The leftmost column of the page is column 0.
      row - The row at which the content is to be updated. The top row of the page is row 0.
      content - The page content to be placed at the specified row and column.

    • getWidth

      int getWidth()

      Gets the width of the page, in text columns.

       

      This value is valid on all PageMessage instances created using the MessageFactory interface. However it may be undefined (and hence have a value of -1) on instances received by an implementation of SubscriptionListener

       

      The first character on a page is at column zero. Therefore the maximum modifiable column is at position (Width - 1).

      Returns:
      The width of the page, in text columns.

    • setWidth

      void setWidth(int width)

      Sets the width of the page, in text columns.

       

      This value is valid on all PageMessage instances created using the MessageFactory interface. However it may be undefined (and hence have a value of -1) on instances received by an implementation of SubscriptionListener.

      The first character on a page is at column zero. Therefore the maximum modifiable column is at position (Width - 1).

      Parameters:
      width - The width of the page, in text columns.

    • getHeight

      int getHeight()

      Gets the height of the page, in text rows.

       

      This value is valid on all PageMessage instances created using the MessageFactory interface, however it may be undefined (and hence have a value of -1) on instances received by an implementation of SubscriptionListener.

       

      The first character on a page is at row zero. Therefore the maximum modifiable row is at position (height - 1).

      Returns:
      The height of the page, in text rows.

    • setHeight

      void setHeight(int height)

      Sets the height of the page, in text rows.

       

      The first character on a page is at row zero. Therefore the maximum modifiable row is at row (height - 1).

      Parameters:
      height - The height of the page, in text rows.

    • getPageType

      String getPageType()

      Gets the type of the page.

       

      The type of the page is available to StreamLink clients and can be used to control the display of the page.

      Returns:
      The type of the page.

    • setPageType

      void setPageType(String pageType)

      Sets the type of the page.

       

      The type of the page is available to StreamLink clients and can be used to control the display of the page.

      Parameters:
      pageType - The type of the page.

    • getUpdatedElements

      List<PageElement> getUpdatedElements()

      Gets a read-only list of the updated page elements.

      Returns:
      The updated page elements.

    • clearFields

      void clearFields()
      Removes all the fields previously added to this PageMessage

    • containsField

      boolean containsField(String fieldName)
      Determines whether the message contains the specified field
      Parameters:
      fieldName - Name of the field.
      Returns:
      true if the message contains the field, otherwise, false.

    • getFields

      List<Field> getFields()
      Gets the fields within this PageMessage, in the order of which the fields were sent. This can include duplicate field names for different values.
      Returns:
      A read-only list of the fields.

    • setField

      void setField(String fieldName, String value)

      Sets a field value.

       

      If the field does not exist in this PageMessage, the field is added to it. Otherwise the existing occurrence of the field is updated to the new value.

      Parameters:
      fieldName - The name of the field.
      value - The new value of the field.
      Throws:
      IllegalArgumentException - Raised when the fieldName is not defined in the Fields configuration file.

    • getField

      String getField(String fieldName)

      Gets the value of the specified field. If the field does not exist in this PageMessage, null is returned.

      Parameters:
      fieldName - The name of the field to get.
      Returns:
      The value of the field with the name fieldName, or null if there is no such field in this PageMessage.
      Throws:
      IllegalArgumentException - Raised when the fieldName is not defined in the Fields configuration file.

    • removeField

      void removeField(String fieldName)
      Removes all occurrences given field from this PageMessage.
      Parameters:
      fieldName - The name of the field to remove.