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SUMMARY: FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
Object | +--Table | +--VisualTable | +--MetapushTable
A data table that can be fed with real-time data
delivered by Lightstreamer Server and displayed into a screen table
according to ADD, UPDATE and DELETE commands received as pushed values,
which instruct the data table to add a row, just modify values on a row
or delete a row.
We call this a "COMMAND logic" behaviour.
The class contains the subscription details and the event handlers
needed to allow Lightstreamer to display the real-time data.
A screen table suitable for the visualization of pushed values
should be made of a matrix of HTML cells. Such cells can be defined at
page loading, through PushPage.cellMetapush(), or can be
attached to the page DOM at any time, as DIV, SPAN or INPUT elements owning
the "source='Lightstreamer'" special attribute, together with proper
"row", "field" and "table" attributes; the latter defines the screen
table id. The association is made when the data table is brought to
the "running" state, through the identifier supplied to
PushPage.addTable(), that must match the screen table id.
A ScreenTableHelper can also be used to this purpose also
enabling the possibility to specify tags other than SPAN DIV and INPUT.
For each pushed update, the involved row is determined and each
value is displayed in a cell that is associated to the involved row
and field. Scrolling operations on rows that are already displayed
may be performed too. By default the new/scrolled value will replace the cell's content
(or its value in case the cell is an INPUT or a TEXTAREA element). It is possible
to override this behavior by specifying a special "update" attribute containing the
name of the attribute of the cell to be updated. Any string can be specified;
moreover a value of a stylesheet can be specified using the "style.attribute"
form (note that the DOM attribute name should be used, not the CSS name; e.g.
"style.backgroundColor" is correct, while "style.background-color" is not).
WARNING: also events like "onclick" can be assigned; in such cases make sure that no
malicious code will be pushed by the Data Adapter (for example through
the injection of undesired JavaScript code).
Note: the cell/field association depends on the value specified in the "field"
attribute of each cell, which should be a valid field descriptor.
Only one cell for each row-field combination is supported.
The initial contents and stylesheets supplied to the cells will
also be used when cell clearing has to be performed (the stylesheet used is the
one supplied through the "class" attribute).
Note that rows that are added or scrolled down to
row numbers for which no cells have been configured will not be
displayed; however, they may be displayed again, if they are scrolled
up after deletion of preceding rows.
More visualization actions can be performed through the event
handlers provided.
See:
Constructor Summary | |
MetapushTable
(<GroupDescriptor> tGroup, <SchemaDescriptor> tSchema, <String> tSubscriptionMode)
Creates an object to be used to describe a data table to be managed with a "COMMAND logic" behaviour. |
Method Summary | |
Number
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getMetapushSortField()
Inquiry method that gets the index of the field currently used as sort field, if available. |
String
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getMetapushSortFieldName()
Inquiry method that gets the name of the field currently used as sort field, if available. |
boolean
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isCommaAsDecimalSeparator()
Inquiry method that gets the type of interpretation to be used to parse the sort field values in order to perform numeric sort. |
boolean
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isDescendingSort()
Inquiry method that gets the sort direction currently configured. |
boolean
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isNumericSort()
Inquiry method that gets the type of sort currently configured. |
void
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onChangingValues(<VisualUpdateInfo> updateInfo)
Event handler that is called by Lightstreamer each time a row of the data table, containing the values of the fields for a key, has been added (because of an ADD command) or changed (because of an UPDATE command). |
void
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onRowUpdate(<Number> rowNumber, <RowInfo> rowInfo)
Event handler that receives the notification that a row of the data table is being displayed on the corresponding cells. |
void
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setLastVisibleRow(<Number> rowNumber)
Setter method that specifies the row number of the last row in the screen table. |
void
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setMetapushFields(<Number> commandPos, <Number> keyPos)
Setter method that configures the special metapush fields. |
void
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setMetapushSort(<FieldDescriptor> sortField, <boolean> descendingSort, <boolean> numericSort, <boolean> commaAsDecimalSeparator)
Setter method that configures the sort policy of the data table. |
Methods inherited from class VisualTable |
setClearOnRemove, setClearOnDisconnected, setClearOnAdd, setPushedHtmlEnabled, isPushedHtmlEnabled, showValues
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Methods inherited from class Table |
getSchema, getGroup, setDataAdapter, getId, setSelector, setItemsRange, setRequestedMaxFrequency, setRequestedBufferSize, setSnapshotRequired, onItemUpdate, onLostUpdates, onEndOfSnapshot, onStart, getClassName
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Constructor Detail |
MetapushTable(<GroupDescriptor> tGroup, <SchemaDescriptor> tSchema, <String> tSubscriptionMode)
tGroup
- A group descriptor object, which identifies the items that provide values for the data table rows. Usually, the group consists of just one item, whose updates are commands that specify whether to ADD, UPDATE or DELETE data table rows. If the group consists of more than one item, then the updates for the different items are simply mixed and concur to the maintenance of the same data table. However, if the same key is used by different items, it refers to distinct rows on the data table. tSchema
- A schema descriptor object, which identifies the fields that represent the data table columns. An Array of field names or a String schema identifier can also be used directly, instead of a schema descriptor object. tSubscriptionMode
- the subscription mode for the items, required by Lightstreamer Server. This kind of data table is suited for COMMAND mode.
Method Detail |
Number getMetapushSortField()
String getMetapushSortFieldName()
boolean isCommaAsDecimalSeparator()
boolean isDescendingSort()
boolean isNumericSort()
void onChangingValues(<VisualUpdateInfo> updateInfo)
updateInfo
- a value object containinig the updated values for all the fields, together with the formatted values and the display settings for the fields. The desired settings can be set in the object, to substitute the default settings, before returning. void onRowUpdate(<Number> rowNumber, <RowInfo> rowInfo)
rowNumber
- The number of the row which is being update. It always refers to a visible row, i.e. a row that exists in the screen table.
rowInfo
- a value object containinig the formatted values to be displayed for the row fields. void setLastVisibleRow(<Number> rowNumber)
rowNumber
- the 1-based row number of the last visible row.
void setMetapushFields(<Number> commandPos, <Number> keyPos)
commandPos
- 1-based index of the "command" field.
keyPos
- 1-based index of the "key" field.
void setMetapushSort(<FieldDescriptor> sortField, <boolean> descendingSort, <boolean> numericSort, <boolean> commaAsDecimalSeparator)
sortField
- a field descriptor object for the field to be used as sort field, or null to disable sorting. A String field name or a Number representing a field position can also be used directly, instead of a field descriptor object.
descendingSort
- [Optional] true or false to perform descending or ascending sort. This parameter is optional; if missing or null, then ascending sort is performed.
numericSort
- [Optional] true or false to perform numeric or alphabetical sort. This parameter is optional; if missing or null, then alphabetical sort is performed.
commaAsDecimalSeparator
- [Optional] true to specify that sort field values are decimal numbers in which the decimal separator is a comma; false to specify it is a dot. This setting is used only if numericSort is true, in which case it is optional, with false as its default value.
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