org.opencms.db.CmsSqlBooleanClause Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* 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, or (at your option) any later version.
*
* 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.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* 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
*/
package org.opencms.db;
import java.util.ArrayList;
import java.util.List;
/**
* Class for generating an SQL boolean expression.
*
* @since 8.0.0
*/
public class CmsSqlBooleanClause implements I_CmsQueryFragment {
/** The list of operands. */
private List m_fragments = new ArrayList();
/** The boolean operator. */
private String m_operator;
/**
* Creates a new boolean clause.
*
* @param operator the boolean operator
*/
public CmsSqlBooleanClause(String operator) {
m_operator = operator;
}
/**
* Creates a boolean "AND" expression.
*
* @param fragments the operands of the "AND"
*
* @return the combined expression
*/
public static CmsSqlBooleanClause makeAnd(I_CmsQueryFragment... fragments) {
CmsSqlBooleanClause result = new CmsSqlBooleanClause("AND");
for (I_CmsQueryFragment fragment : fragments) {
result.addCondition(fragment);
}
return result;
}
/**
* Creates a boolean "OR" expression.
*
* @param fragments the operands of the "OR"
*
* @return the combined expressiong
*/
public static CmsSqlBooleanClause makeOr(I_CmsQueryFragment... fragments) {
CmsSqlBooleanClause result = new CmsSqlBooleanClause("OR");
for (I_CmsQueryFragment fragment : fragments) {
result.addCondition(fragment);
}
return result;
}
/**
* Adds an operand to the boolean expression.
*
* @param fragment the operand
*
* @return this object instance
*/
public CmsSqlBooleanClause addCondition(I_CmsQueryFragment fragment) {
m_fragments.add(fragment);
return this;
}
/**
* @see org.opencms.db.I_CmsQueryFragment#visit(org.opencms.db.CmsStatementBuilder)
*/
public void visit(CmsStatementBuilder builder) {
String connector = " " + m_operator + " ";
if (m_fragments.size() == 0) {
throw new IllegalStateException();
} else if (m_fragments.size() == 1) {
m_fragments.get(0).visit(builder);
} else {
builder.add("(");
for (int i = 0; i < m_fragments.size(); i++) {
if (i != 0) {
builder.add(connector);
}
m_fragments.get(i).visit(builder);
}
builder.add(")");
}
}
}