CustomExpression.java

/*
Copyright (c) 2008 Health Market Science, Inc.

This library 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.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
USA

You can contact Health Market Science at info@healthmarketscience.com
or at the following address:

Health Market Science
2700 Horizon Drive
Suite 200
King of Prussia, PA 19406
*/

package com.healthmarketscience.sqlbuilder;

import java.io.IOException;

import com.healthmarketscience.common.util.AppendableExt;


/**
 * Outputs the given custom object surrounded by parentheses
 * <code>"(<customExpr>)"</code>.  Acts like {@link CustomSql} for
 * expressions.  If the given expression is <code>null</code>, nothing will be
 * output for the expression.
 *
 * @author James Ahlborn
 */
public class CustomExpression extends Expression
{
  private SqlObject _expr;

  public CustomExpression(Object exprObj) {
    this((exprObj != null) ?
         (new CustomSql(exprObj)) :
         (SqlObject)null);
  }
  
  public CustomExpression(SqlObject exprStr) {
    _expr = exprStr;
  }

  @Override
  public boolean isEmpty() { return(_expr == null); }

  @Override
  protected void collectSchemaObjects(ValidationContext vContext) {
    if(_expr != null) {
      _expr.collectSchemaObjects(vContext);
    }
  }
    
  @Override
  public void appendTo(AppendableExt app) throws IOException {
    appendCustomIfNotNull(app, _expr);
  }
  
}