defaultvtimoddeferpolicy.java

derby database source code.good for you.

/*

   Derby - Class org.apache.derby.impl.sql.compile.DefaultVTIModDeferPolicy

   Copyright 2003, 2004 The Apache Software Foundation or its licensors, as applicable.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */

package	org.apache.derby.impl.sql.compile;

import org.apache.derby.vti.DeferModification;

/**
 * This class implements the default policy for defering modifications to virtual
 * tables.
 */
class DefaultVTIModDeferPolicy implements DeferModification
{
    private final String targetVTIClassName;
    private final boolean VTIResultSetIsSensitive;

    DefaultVTIModDeferPolicy( String targetVTIClassName,
                              boolean VTIResultSetIsSensitive)
    {
        this.targetVTIClassName = targetVTIClassName;
        this.VTIResultSetIsSensitive = VTIResultSetIsSensitive;
    }

    /**
     * @see org.apache.derby.vti.DeferModification#alwaysDefer
     */
    public boolean alwaysDefer( int statementType)
    {
        return false;
    }
          
    /**
     * @see org.apache.derby.vti.DeferModification#columnRequiresDefer
     */
    public boolean columnRequiresDefer( int statementType,
                                        String columnName,
                                        boolean inWhereClause)
    {
        switch( statementType)
        {
        case DeferModification.INSERT_STATEMENT:
            return false;

        case DeferModification.UPDATE_STATEMENT:
            return VTIResultSetIsSensitive && inWhereClause;

        case DeferModification.DELETE_STATEMENT:
            return false;
        }
        return false; // Should not get here.
    } // end of columnRequiresDefer

    /**
     * @see org.apache.derby.vti.DeferModification#subselectRequiresDefer(int,String,String)
     */
    public boolean subselectRequiresDefer( int statementType,
                                           String schemaName,
                                           String tableName)
    {
        return false;
    } // end of subselectRequiresDefer( statementType, schemaName, tableName)

    /**
     * @see org.apache.derby.vti.DeferModification#subselectRequiresDefer(int, String)
     */
    public boolean subselectRequiresDefer( int statementType,
                                           String VTIClassName)
    {
        return targetVTIClassName.equals( VTIClassName);
    } // end of subselectRequiresDefer( statementType, VTIClassName)

    public void modificationNotify( int statementType,
                                    boolean deferred)
    {}
}