com.espertech.esper.client.soda.SelectClauseStreamWildcard Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of esper Show documentation
Complex event processing and event series analysis component
There is a newer version: 7.1.0
/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  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.StringWriter;

/**
 * For use in a select clause, this element in a select clause defines that for a given stream we want to
 * select the underlying type. Most often used in joins to select wildcard from one of the joined streams.
 * 
 * For example:
 * 
select streamOne.* from StreamOne as streamOne, StreamTwo as streamTwo
 */
public class SelectClauseStreamWildcard implements SelectClauseElement {
    private String streamName;
    private String optionalColumnName;
    private static final long serialVersionUID = -1827870385836445548L;

    /**
     * Ctor.
     */
    public SelectClauseStreamWildcard() {
    }

    /**
     * Ctor.
     *
     * @param streamName         is the name assigned to a stream
     * @param optionalColumnName is the name to assign to the column carrying the streams generated events, or
     *                           null if the event should not appear in a column
     */
    public SelectClauseStreamWildcard(String streamName, String optionalColumnName) {
        this.streamName = streamName;
        this.optionalColumnName = optionalColumnName;
    }

    /**
     * Returns the stream name (e.g. select streamName.* as colName from MyStream as streamName)
     *
     * @return name
     */
    public String getStreamName() {
        return streamName;
    }

    /**
     * Returns the optional column name (e.g. select streamName.* as colName from MyStream as streamName)
     *
     * @return name of column, or null if none defined
     */
    public String getOptionalColumnName() {
        return optionalColumnName;
    }

    /**
     * Sets the stream name.
     *
     * @param streamName stream name
     */
    public void setStreamName(String streamName) {
        this.streamName = streamName;
    }

    /**
     * Sets the column name.
     *
     * @param optionalColumnName column name
     */
    public void setOptionalColumnName(String optionalColumnName) {
        this.optionalColumnName = optionalColumnName;
    }

    /**
     * Renders the element in textual representation.
     *
     * @param writer to output to
     */
    public void toEPLElement(StringWriter writer) {
        writer.write(streamName);
        writer.write(".*");
        if (optionalColumnName != null) {
            writer.write(" as ");
            writer.write(optionalColumnName);
        }
    }
}