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/**
 *
 */
package patterntesting.runtime.dbc;

import org.slf4j.*;

import patterntesting.runtime.util.Assertions;

/**
 * The Class DbC.
 *
 * @author oliver
 */
public final class DbC {

	private static final Logger LOG = LoggerFactory.getLogger(DbC.class);

    static {
        if (Assertions.enabled) {
            LOG.debug("DbC is active");
        } else {
            LOG.debug("DbC deactivated - call 'java -ea' (SunVM) to activate it");
        }
    }

    /** No need to instantiate it (utility class). */
    private DbC() {}

    /**
     * Use this method to describe the condition which must be true when your
     * method is called.
     *
     * @param precondition e.g. (arg0 != null)
     */
    public static void require(final boolean precondition) {
        require(precondition, "precondition violated");
    }

    /**
     * Use this method to describe the condition which must be true when your
     * method is called.
     *
     * @param precondition e.g. (arg0 != null)
     * @param message e.g. "null argument is not allowed"
     */
    public static void require(final boolean precondition, final Object message) {
        if (Assertions.enabled && !precondition) {
            throw new ContractViolation(message);
       }
    }

    /**
     * Use this method to describe the condition which must be true when the
     * preconditions were true and your method is finished.
     *
     * @param postcondition e.g. (value > 0)
     */
    public static void ensure(final boolean postcondition) {
        ensure(postcondition, "postcondition violated");
    }

    /**
     * Use this method to describe the condition which must be true when the
     * preconditions were true and your method is finished.
     *
     * @param postcondition e.g. (value > 0)
     * @param message e.g. "value must be positive"
     */
    public static void ensure(final boolean postcondition, final Object message) {
        if (Assertions.enabled && !postcondition) {
            throw new ContractViolation(message);
        }
    }

}