liquibase-core/src/main/java/liquibase/parser/core/ParsedNode.java
public <T> T getChildValue(String namespace, String nodename, T defaultValue) throws ParsedNodeException {
        T value = (T) getChildValue(namespace, nodename, defaultValue.getClass());
        if (value == null) {
            return defaultValue;
        }
        return value;
    }
public <T> T getChildValue(String namespace, String nodename, T defaultValue) throws ParsedNodeException {
        T value = (T) getChildValue(namespace, nodename, defaultValue.getClass());
        if (value == null) {
            return defaultValue;
        }
        return value;
    }
Convenience method for {@link #getChildValue(String, String, Class)} but returns the passed defaultValue if the given node is null or not defined.