fr.keyconsulting.oliphant.postgresql.PostgreSQLListenerAuxiliary.java Source code

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Here is the source code for fr.keyconsulting.oliphant.postgresql.PostgreSQLListenerAuxiliary.java

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/*******************************************************************************
    
   Copyright (C) 2009-2010 Key Consulting
    
   This file is part of Oliphant.
    
   Oliphant 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 3 of the License, or
   (at your option) any later version.
    
   Oliphant 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 Oliphant.  If not, see <http://www.gnu.org/licenses/>.
    
*******************************************************************************/

package fr.keyconsulting.oliphant.postgresql;

import java.util.Iterator;

import org.hibernate.HibernateException;
import org.hibernate.mapping.*;
import org.hibernate.cfg.Configuration;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.Mapping;

public class PostgreSQLListenerAuxiliary extends AbstractAuxiliaryDatabaseObject {
    private static final long serialVersionUID = 1L;
    private Configuration config;

    public PostgreSQLListenerAuxiliary(Configuration config) {
        addDialectScope("org.hibernate.dialect.PostgreSQLDialect");
        this.config = config;
    }

    public String sqlCreateString(Dialect dialect, Mapping mapping, String defaultCatalog, String defaultSchema) {
        StringBuilder sb = new StringBuilder();

        for (Iterator i = config.getClassMappings(); i.hasNext();) {
            PersistentClass c = (PersistentClass) i.next();
            Table table = c.getTable();
            if (table.getPrimaryKey().getColumnSpan() > 1) {
                throw new HibernateException(
                        "Oliphant does not support primary keys that span multiple columns. Objects of class "
                                + c.getClassName() + " will not be monitored for changes.");
            }
            String tableName = table.getName().toLowerCase();

            String idColName = table.getPrimaryKey().getColumn(0).getName();

            Iterator verCols = c.getVersion().getColumnIterator();
            if (!verCols.hasNext()) {
                throw new HibernateException(
                        "Oliphant does not support version properties that span multiple columns. Objects of class "
                                + c.getClassName() + " will not be monitored for changes.");
            }
            Column verCol = (Column) verCols.next();
            String verColName = verCol.getName();
            if (verCols.hasNext()) {
                throw new HibernateException("Oliphant does not support non versioned entities. Objects of class "
                        + c.getClassName() + " will not be monitored for changes.");
            }
            sb.append("CREATE OR REPLACE FUNCTION oliphant_" + tableName + "() RETURNS TRIGGER AS $$\n");
            sb.append("   DECLARE\n");
            sb.append("      VERSION TEXT;\n");
            sb.append("   BEGIN\n");
            sb.append("      IF TG_OP = 'UPDATE' THEN\n");
            sb.append("         VERSION := NEW." + verColName + ";\n");
            sb.append("      ELSIF TG_OP = 'DELETE' THEN\n");
            sb.append("         VERSION := -1;\n");
            sb.append("      END IF;\n");
            sb.append("      PERFORM send_notify('oliphant', '" + tableName + "#' || encode(text(OLD." + idColName
                    + ")::bytea,'base64') || '###' || encode(text(VERSION)::bytea,'base64')); RETURN NULL;\n");
            sb.append("   END;\n");
            sb.append("$$ LANGUAGE 'plpgsql';\n");
            sb.append("\n");
            sb.append("CREATE TRIGGER oliphant_" + tableName + "_trg\n");
            sb.append("   AFTER DELETE OR UPDATE ON " + tableName + "\n");
            sb.append("   FOR EACH ROW EXECUTE PROCEDURE oliphant_" + tableName + "();\n");
            sb.append("\n");
        }

        return sb.toString();
    }

    public String sqlDropString(Dialect dialect, String defaultCatalog, String defaultSchema) {
        StringBuilder sb = new StringBuilder();

        for (Iterator i = config.getClassMappings(); i.hasNext();) {
            PersistentClass c = (PersistentClass) i.next();
            Table table = c.getTable();
            if ((table.getPrimaryKey().getColumnSpan() == 1) && (c.getVersion().getColumnSpan() == 1)) {
                String tableName = table.getName().toLowerCase();

                sb.append("DROP FUNCTION oliphant_" + tableName + "()\n");
                sb.append("\n");
            }
        }

        return sb.toString();
    }

}