org.apache.cayenne.velocity.BindEqualDirective Maven / Gradle / Ivy

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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 PreparedStatement parameter text
 * for "= ?". If null value is encountered, generated text will look like "IS NULL".
 * Usage in Velocity template is "WHERE SOME_COLUMN #bindEqual($xyz)".
 * 
 * @since 1.1
 */
public class BindEqualDirective extends BindDirective {

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

    @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 NULL");
        }
    }
}