/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package com.espertech.esper.client.soda;
import java.io.Serializable;
import java.io.StringWriter;
/**
* An abstract base class for a named or unnamed stream.
* <p>
* Named streams provide an as-name for the stream, for example "select * from MyEvents(id=10) as StreamZero".
* Unnamed streams provide no as-name for the stream, for example "select * from MyEvents(id=10)".
*/
public abstract class Stream implements Serializable
{
private static final long serialVersionUID = 0L;
private String streamName;
/**
* Ctor.
*/
public Stream() {
}
/**
* Renders the stream in textual representation.
* @param writer to output to
* @param formatter for newline-whitespace formatting
*/
public abstract void toEPLStream(StringWriter writer, EPStatementFormatter formatter);
/**
* Renders the stream in textual representation any stream options, if present.
* @param writer to output to
*/
public abstract void toEPLStreamOptions(StringWriter writer);
/**
* Renders the stream type under a non-complete textual representation for tool use
* @param writer to output to
*/
public abstract void toEPLStreamType(StringWriter writer);
/**
* Ctor.
* @param streamName is null for unnamed streams, or a stream name for named streams.
*/
protected Stream(String streamName)
{
this.streamName = streamName;
}
/**
* Returns the stream name.
* @return name of stream, or null if unnamed.
*/
public String getStreamName()
{
return streamName;
}
/**
* Sets the stream name.
* @param streamName is the name of stream, or null if unnamed.
*/
public void setStreamName(String streamName)
{
this.streamName = streamName;
}
/**
* Renders the clause in textual representation.
* @param writer to output to
* @param formatter for newline-whitespace formatting
*/
public void toEPL(StringWriter writer, EPStatementFormatter formatter)
{
toEPLStream(writer, formatter);
if (streamName != null)
{
writer.write(" as ");
writer.write(streamName);
}
toEPLStreamOptions(writer);
}
}