/// <summary>
/// Returns the statement by the given statement name. Returns null if a statement
/// of that name has not been created, or if the statement by that name has been
/// destroyed.
/// </summary>
/// <param name="name">is the statement name to return the statement for</param>
/// <returns>
/// statement for the given name, or null if no such started or stopped statement
/// exists
/// </returns>
public EPStatement GetStatement(string name)
{
lock (_statementTable)
{
var statementWrapper = _statementTable.Get(name);
if ((statementWrapper != null) && statementWrapper.IsAlive)
{
return(statementWrapper.Target);
}
}
using (var wrapper = CreateControlManager())
{
try
{
return(WithExceptionHandling(
delegate
{
var controlManager = wrapper.Channel;
var statement = controlManager.GetStatement(_instanceId, name);
var statementWrapper = new CatalystStatement(_adapter, statement);
BindStatement(statementWrapper);
return statementWrapper;
}));
}
catch (ItemNotFoundException)
{
return(null);
}
}
}
/// <summary>
/// Creates and starts a prepared statement.
/// <para/>
/// The statement name is optimally a unique name. If a statement of the same name
/// has already been created, the engine assigns a postfix to create a unique
/// statement name.
/// <para/>
/// Accepts an application defined user data object associated with the statement.
/// The <em>user object</em> is a single, unnamed field that is stored with every
/// statement. Applications may put arbitrary objects in this field or a null value.
/// </summary>
/// <param name="prepared">is the prepared statement for which all substitution values have been provided</param>
/// <param name="statementName">is the name to assign to the statement for use in managing the statement</param>
/// <param name="userObject">is the application-defined user object</param>
/// <returns>
/// EPStatement to poll data from or to add listeners to
/// </returns>
/// <throws>EPException when the prepared statement was not valid</throws>
public EPStatement Create(EPPreparedStatement prepared, string statementName, object userObject)
{
if (prepared == null)
{
throw new ArgumentNullException("prepared");
}
var cprepared = prepared as CatalystPreparedStatement;
if (cprepared == null)
{
throw new ArgumentException("prepared statement was of incorrect type", "prepared");
}
using (var wrapper = CreateControlManager())
{
return(WithExceptionHandling(
delegate
{
var controlManager = wrapper.Channel;
var statementArgs = new StatementCreationArgs();
statementArgs.PreparedStatementId = cprepared.Id;
statementArgs.StatementName = statementName;
statementArgs.StatementText = null;
var statement = controlManager.CreatePrepared(_instanceId, statementArgs);
var statementWrapper = new CatalystStatement(_adapter, statement, userObject);
BindStatement(statementWrapper);
return statementWrapper;
}));
}
}
/// <summary>
/// Create and starts an event pattern statement for the expressing string passed.
/// <para/>
/// The engine assigns a unique name to the statement.
/// </summary>
/// <param name="onExpression">must follow the documented syntax for pattern statements</param>
/// <returns>
/// EPStatement to poll data from or to add listeners to
/// </returns>
/// <throws>EPException when the expression was not valid</throws>
public EPStatement CreatePattern(string onExpression)
{
using (var wrapper = CreateControlManager())
{
return(WithExceptionHandling(
delegate
{
var controlManager = wrapper.Channel;
var statementArgs = new StatementCreationArgs();
statementArgs.StatementText = onExpression;
var statement = controlManager.CreatePattern(_instanceId, statementArgs);
var statementWrapper = new CatalystStatement(_adapter, statement);
BindStatement(statementWrapper);
return statementWrapper;
}));
}
}
/// <summary>
/// Create and starts an EPL statement.
/// <para/>
/// Accepts an application defined user data object associated with the statement.
/// The <em>user object</em> is a single, unnamed field that is stored with every
/// statement. Applications may put arbitrary objects in this field or a null value.
/// </summary>
/// <param name="eplStatement">is the query language statement</param>
/// <param name="userObject">is the application-defined user object</param>
/// <returns>
/// EPStatement to poll data from or to add listeners to
/// </returns>
/// <throws>EPException when the expression was not valid</throws>
public EPStatement CreateEPL(string eplStatement, object userObject)
{
using (var wrapper = CreateControlManager())
{
return(WithExceptionHandling(
delegate
{
var controlManager = wrapper.Channel;
var statementArgs = new StatementCreationArgs();
statementArgs.StatementText = eplStatement;
var statement = controlManager.CreateEPL(_instanceId, statementArgs);
var statementWrapper = new CatalystStatement(_adapter, statement, userObject);
BindStatement(statementWrapper);
return statementWrapper;
}));
}
}
private void BindStatement(CatalystStatement statement)
{
lock (_statementTable) {
_statementTable[statement.Id] = new WeakReference <CatalystStatement>(statement);
}
}
