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JSqlParser parses an SQL statement and translate it into a hierarchy of Java classes. The generated hierarchy can be navigated using the Visitor Pattern.

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/*
 * #%L
 * JSQLParser library
 * %%
 * Copyright (C) 2004 - 2013 JSQLParser
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as 
 * published by the Free Software Foundation, either version 2.1 of the 
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public 
 * License along with this program.  If not, see
 * .
 * #L%
 */
package net.sf.jsqlparser.expression;

import java.util.List;

import net.sf.jsqlparser.statement.select.PlainSelect;

/**
 * CASE/WHEN expression.
 *
 * Syntax:
 *  * CASE
 * WHEN condition THEN expression
 * [WHEN condition THEN expression]...
 * [ELSE expression]
 * END
 * 
 *
 * 

 * or 

 * 

 *
 *  * CASE expression
 * WHEN condition THEN expression
 * [WHEN condition THEN expression]...
 * [ELSE expression]
 * END
 * 
 *
 * See also: https://aurora.vcu.edu/db2help/db2s0/frame3.htm#casexp
 * http://sybooks.sybase.com/onlinebooks/group-as/asg1251e /commands/
 *
 * @ebt-link;pt=5954?target=%25N%15_52628_START_RESTART_N%25
 *
 *
 * @author Havard Rast Blok
 */
public class CaseExpression implements Expression {

	private Expression switchExpression;
	private List whenClauses;
	private Expression elseExpression;

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.sf.jsqlparser.expression.Expression#accept(net.sf.jsqlparser.expression.ExpressionVisitor)
	 */
	@Override
	public void accept(ExpressionVisitor expressionVisitor) {
		expressionVisitor.visit(this);
	}

	/**
	 * @return Returns the switchExpression.
	 */
	public Expression getSwitchExpression() {
		return switchExpression;
	}

	/**
	 * @param switchExpression The switchExpression to set.
	 */
	public void setSwitchExpression(Expression switchExpression) {
		this.switchExpression = switchExpression;
	}

	/**
	 * @return Returns the elseExpression.
	 */
	public Expression getElseExpression() {
		return elseExpression;
	}

	/**
	 * @param elseExpression The elseExpression to set.
	 */
	public void setElseExpression(Expression elseExpression) {
		this.elseExpression = elseExpression;
	}

	/**
	 * @return Returns the whenClauses.
	 */
	public List getWhenClauses() {
		return whenClauses;
	}

	/**
	 * @param whenClauses The whenClauses to set.
	 */
	public void setWhenClauses(List whenClauses) {
		this.whenClauses = whenClauses;
	}

	@Override
	public String toString() {
		return "CASE " + ((switchExpression != null) ? switchExpression + " " : "")
				+ PlainSelect.getStringList(whenClauses, false, false) + " "
				+ ((elseExpression != null) ? "ELSE " + elseExpression + " " : "") + "END";
	}
}