groovy-core/src/main/groovy/lang/Interceptor.java

package groovy.lang;

/**
 * Implementers of this interface can be registered in the ProxyMetaClass for
 * notifications about method calls for objects managed by the ProxyMetaClass.
 * See groovy/lang/InterceptorTest.groovy for details.
 * @author Dierk Koenig
 */
public interface Interceptor {
    /**
     * This code is executed before the method is optionally called.
     * @param object        receiver object for the method call
     * @param methodName    name of the method to call
     * @param arguments     arguments to the method call
     * @return any arbitrary result that replaces the result of the
     * original method call only if doInvoke() returns false and afterInvoke()
     * relays this result.
     */
    Object beforeInvoke(Object object, String methodName, Object[] arguments);
    /**
     * This code is executed after the method is optionally called.
     * @param object        receiver object for the called method
     * @param methodName    name of the called method
     * @param arguments     arguments to the called method
     * @param result        result of the executed method call or result of beforeInvoke if method was not called
     * @return any arbitrary result that can replace the result of the
     * original method call. Typically, the result parameter is returned.
     */
    Object afterInvoke(Object object, String methodName, Object[] arguments, Object result);
    /**
     * @return whether the target method should be invoked at all.
     */
    boolean doInvoke();
}