001/*-
002 * #%L
003 * HAPI FHIR - Core Library
004 * %%
005 * Copyright (C) 2014 - 2025 Smile CDR, Inc.
006 * %%
007 * Licensed under the Apache License, Version 2.0 (the "License");
008 * you may not use this file except in compliance with the License.
009 * You may obtain a copy of the License at
010 *
011 *      http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 * #L%
019 */
020package ca.uhn.fhir.interceptor.executor;
021
022import ca.uhn.fhir.interceptor.api.IBaseInterceptorBroadcaster.IInterceptorFilterHook;
023
024import java.util.function.Supplier;
025
026/**
027 * Wraps a Supplier with advice from a filter hook.
028 */
029public class SupplierFilterHookWrapper<T> implements Supplier<T> {
030        private final IInterceptorFilterHook myAdvice;
031        private final Supplier<T> myTarget;
032        private final Supplier<String> myMessageSupplier;
033
034        public SupplierFilterHookWrapper(
035                        Supplier<T> theTarget, IInterceptorFilterHook theAdvice, Supplier<String> theCauseDescriptionSupplier) {
036                myAdvice = theAdvice;
037                myTarget = theTarget;
038                myMessageSupplier = theCauseDescriptionSupplier;
039        }
040
041        @Override
042        public T get() {
043                SupplierRunnable<T> trackingSupplierWrapper = new SupplierRunnable<>(myTarget);
044
045                myAdvice.wrapCall(trackingSupplierWrapper);
046
047                if (!trackingSupplierWrapper.wasExecuted()) {
048                        throw new IllegalStateException(
049                                        "Supplier was not executed in filter produced by " + myMessageSupplier.get());
050                }
051
052                return trackingSupplierWrapper.getResult();
053        }
054
055        /**
056         * Adapt a Supplier to Runnable.
057         * We use a Runnable for a simpler api for callers.
058         * @param <T>
059         */
060        static class SupplierRunnable<T> implements Runnable {
061                private final Supplier<T> myTarget;
062                private boolean myExecutedFlag = false;
063                private T myResult = null;
064
065                SupplierRunnable(Supplier<T> theTarget) {
066                        myTarget = theTarget;
067                }
068
069                public void run() {
070                        myExecutedFlag = true;
071                        myResult = myTarget.get();
072                }
073
074                public boolean wasExecuted() {
075                        return myExecutedFlag;
076                }
077
078                public T getResult() {
079                        return myResult;
080                }
081        }
082}