org.hibernate.sql.DerbyCaseFragment.java Source code

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Here is the source code for org.hibernate.sql.DerbyCaseFragment.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.sql;

import java.util.Iterator;
import java.util.Map;

/**
 * @author Simon Johnston
 * @see org.hibernate.dialect.DerbyDialect
 */
public class DerbyCaseFragment extends CaseFragment {

    /**
     * From http://www.jroller.com/comments/kenlars99/Weblog/cloudscape_soon_to_be_derby
     * <p/>
     * The problem we had, was when Hibernate does a select with a case statement, for joined subclasses.
     * This seems to be because there was no else at the end of the case statement (other dbs seem to not mind).
     */
    public String toFragmentString() {
        StringBuilder buf = new StringBuilder(cases.size() * 15 + 10);
        buf.append("case"); //$NON-NLS-1
        Iterator iter = cases.entrySet().iterator();
        while (iter.hasNext()) {
            Map.Entry me = (Map.Entry) iter.next();
            buf.append(" when ")//$NON-NLS-1
                    .append(me.getKey()).append(" is not null then ")//$NON-NLS-1
                    .append(me.getValue());
        }
        // null is not considered the same type as Integer.
        buf.append(" else -1"); //$NON-NLS-1
        buf.append(" end"); //$NON-NLS-1
        if (returnColumnName != null) {
            buf.append(" as ")//$NON-NLS-1
                    .append(returnColumnName);
        }
        return buf.toString();
    }
}