Java tutorial
/* * Hibernate, Relational Persistence for Idiomatic Java * * Copyright (c) 2010, Red Hat Inc. or third-party contributors as * indicated by the @author tags or express copyright attribution * statements applied by the authors. All third-party contributions are * distributed under license by Red Hat Inc. * * This copyrighted material is made available to anyone wishing to use, modify, * copy, or redistribute it subject to the terms and conditions of the GNU * Lesser General Public License, as published by the Free Software Foundation. * * 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 Lesser General Public License * for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this distribution; if not, write to: * Free Software Foundation, Inc. * 51 Franklin Street, Fifth Floor * Boston, MA 02110-1301 USA */ package jef.database.query.function; import java.util.Collections; import java.util.List; import javax.persistence.PersistenceException; import jef.database.jsqlparser.expression.Function; import jef.database.jsqlparser.expression.operators.relational.ExpressionList; import jef.database.jsqlparser.visitor.Expression; import org.apache.commons.lang.ArrayUtils; /** * A function which takes no arguments * * @author Michi */ public class NoArgSQLFunction implements SQLFunction { private boolean hasParenthesesIfNoArguments; private String name; public NoArgSQLFunction(String name) { this(name, true); } public NoArgSQLFunction(String name, boolean hasParenthesesIfNoArguments) { this.hasParenthesesIfNoArguments = hasParenthesesIfNoArguments; this.name = name; } public boolean hasArguments() { return false; } public boolean hasParenthesesIfNoArguments() { return hasParenthesesIfNoArguments; } public String getName() { return name; } @SuppressWarnings("unchecked") public Expression renderExpression(List<Expression> args) { if (args.size() > 0) { throw new PersistenceException("function takes no arguments: " + name); } Function func = new Function(name); if (hasParenthesesIfNoArguments) { func.setParameters(new ExpressionList(Collections.EMPTY_LIST)); } return func; } public boolean needEscape() { return false; } public String[] requiresUserFunction() { return ArrayUtils.EMPTY_STRING_ARRAY; } }