/*****************************************************************
 *   Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.cayenne.velocity;

import java.io.IOException;
import java.io.Writer;

import org.apache.cayenne.access.translator.ParameterBinding;
import org.apache.velocity.context.InternalContextAdapter;

/**
 * A custom Velocity directive to create a set of SQL conditions to check unequality of an
 * ObjectId of an object. Usage in Velocity template is "WHERE
 * #bindObjectNotEqual($object)" or "WHERE #bindObjectNotEqual($object $columns
 * $idValues)".
 * 
 * @since 3.0
 */
public class BindObjectNotEqualDirective extends BindObjectEqualDirective {

    @Override
    public String getName() {
        return "bindObjectNotEqual";
    }

    @Override
    protected void renderColumn(
            InternalContextAdapter context,
            Writer writer,
            Object columnName,
            int columnIndex) throws IOException {

        if (columnIndex > 0) {
            writer.write(" OR ");
        }

        writer.write(columnName.toString());
    }

    @Override
    protected void render(
            InternalContextAdapter context,
            Writer writer,
            ParameterBinding binding) throws IOException {

        if (binding.getValue() != null) {
            bind(context, binding);
            writer.write("<> ?");
        }
        else {
            writer.write("IS NOT NULL");
        }
    }
}