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| 1 | +/* |
| 2 | + * Licensed to the Apache Software Foundation (ASF) under one |
| 3 | + * or more contributor license agreements. See the NOTICE file |
| 4 | + * distributed with this work for additional information |
| 5 | + * regarding copyright ownership. The ASF licenses this file |
| 6 | + * to you under the Apache License, Version 2.0 (the |
| 7 | + * "License"); you may not use this file except in compliance |
| 8 | + * with the License. You may obtain a copy of the License at |
| 9 | + * |
| 10 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | + * |
| 12 | + * Unless required by applicable law or agreed to in writing, |
| 13 | + * software distributed under the License is distributed on an |
| 14 | + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | + * KIND, either express or implied. See the License for the |
| 16 | + * specific language governing permissions and limitations |
| 17 | + * under the License. |
| 18 | + */ |
| 19 | +package org.apache.maven.impl.cache; |
| 20 | + |
| 21 | +import java.util.ArrayList; |
| 22 | +import java.util.HashMap; |
| 23 | +import java.util.List; |
| 24 | +import java.util.Map; |
| 25 | +import java.util.function.Function; |
| 26 | + |
| 27 | +import org.apache.maven.api.cache.BatchRequestException; |
| 28 | +import org.apache.maven.api.cache.MavenExecutionException; |
| 29 | +import org.apache.maven.api.cache.RequestCache; |
| 30 | +import org.apache.maven.api.cache.RequestResult; |
| 31 | +import org.apache.maven.api.services.Request; |
| 32 | +import org.apache.maven.api.services.Result; |
| 33 | + |
| 34 | +/** |
| 35 | + * Abstract implementation of the {@link RequestCache} interface, providing common caching mechanisms |
| 36 | + * for executing and caching request results in Maven. |
| 37 | + * <p> |
| 38 | + * This class implements caching strategies for individual and batch requests, ensuring that results |
| 39 | + * are stored and reused where appropriate to optimize performance. |
| 40 | + * </p> |
| 41 | + * |
| 42 | + * @since 4.0.0 |
| 43 | + */ |
| 44 | +public abstract class AbstractRequestCache implements RequestCache { |
| 45 | + |
| 46 | + /** |
| 47 | + * Executes and optionally caches a single request. |
| 48 | + * <p> |
| 49 | + * The caching behavior is determined by the specific implementation of {@link #doCache(Request, Function)}. |
| 50 | + * If caching is enabled, the result is retrieved from the cache or computed using the supplier function. |
| 51 | + * </p> |
| 52 | + * |
| 53 | + * @param <REQ> The request type |
| 54 | + * @param <REP> The response type |
| 55 | + * @param req The request object used as the cache key |
| 56 | + * @param supplier The function that provides the response if not cached |
| 57 | + * @return The cached or computed response |
| 58 | + */ |
| 59 | + @Override |
| 60 | + @SuppressWarnings("all") |
| 61 | + public <REQ extends Request<?>, REP extends Result<REQ>> REP request(REQ req, Function<REQ, REP> supplier) { |
| 62 | + CachingSupplier<REQ, REP> cs = doCache(req, supplier); |
| 63 | + return cs.apply(req); |
| 64 | + } |
| 65 | + |
| 66 | + /** |
| 67 | + * Executes and optionally caches a batch of requests. |
| 68 | + * <p> |
| 69 | + * This method processes a list of requests, utilizing caching where applicable and executing |
| 70 | + * only the non-cached requests using the provided supplier function. |
| 71 | + * </p> |
| 72 | + * <p> |
| 73 | + * If any request in the batch fails, a {@link BatchRequestException} is thrown, containing |
| 74 | + * details of all failed requests. |
| 75 | + * </p> |
| 76 | + * |
| 77 | + * @param <REQ> The request type |
| 78 | + * @param <REP> The response type |
| 79 | + * @param reqs List of requests to process |
| 80 | + * @param supplier Function to execute the batch of requests |
| 81 | + * @return List of results corresponding to the input requests |
| 82 | + * @throws BatchRequestException if any request in the batch fails |
| 83 | + */ |
| 84 | + @Override |
| 85 | + @SuppressWarnings("unchecked") |
| 86 | + public <REQ extends Request<?>, REP extends Result<REQ>> List<REP> requests( |
| 87 | + List<REQ> reqs, Function<List<REQ>, List<REP>> supplier) { |
| 88 | + final Map<REQ, Object> nonCachedResults = new HashMap<>(); |
| 89 | + List<RequestResult<REQ, REP>> allResults = new ArrayList<>(reqs.size()); |
| 90 | + |
| 91 | + Function<REQ, REP> individualSupplier = req -> { |
| 92 | + synchronized (nonCachedResults) { |
| 93 | + while (!nonCachedResults.containsKey(req)) { |
| 94 | + try { |
| 95 | + nonCachedResults.wait(); |
| 96 | + } catch (InterruptedException e) { |
| 97 | + Thread.currentThread().interrupt(); |
| 98 | + throw new RuntimeException(e); |
| 99 | + } |
| 100 | + } |
| 101 | + Object val = nonCachedResults.get(req); |
| 102 | + if (val instanceof CachingSupplier.AltRes altRes) { |
| 103 | + uncheckedThrow(altRes.throwable); |
| 104 | + } |
| 105 | + return (REP) val; |
| 106 | + } |
| 107 | + }; |
| 108 | + |
| 109 | + List<CachingSupplier<REQ, REP>> suppliers = new ArrayList<>(reqs.size()); |
| 110 | + List<REQ> nonCached = new ArrayList<>(); |
| 111 | + for (REQ req : reqs) { |
| 112 | + CachingSupplier<REQ, REP> cs = doCache(req, individualSupplier); |
| 113 | + suppliers.add(cs); |
| 114 | + if (cs.getValue() == null) { |
| 115 | + nonCached.add(req); |
| 116 | + } |
| 117 | + } |
| 118 | + |
| 119 | + if (!nonCached.isEmpty()) { |
| 120 | + synchronized (nonCachedResults) { |
| 121 | + try { |
| 122 | + List<REP> reps = supplier.apply(nonCached); |
| 123 | + for (int i = 0; i < reps.size(); i++) { |
| 124 | + nonCachedResults.put(nonCached.get(i), reps.get(i)); |
| 125 | + } |
| 126 | + } catch (MavenExecutionException e) { |
| 127 | + // If batch request fails, mark all non-cached requests as failed |
| 128 | + for (REQ req : nonCached) { |
| 129 | + nonCachedResults.put( |
| 130 | + req, new CachingSupplier.AltRes(e.getCause())); // Mark as processed but failed |
| 131 | + } |
| 132 | + } finally { |
| 133 | + nonCachedResults.notifyAll(); |
| 134 | + } |
| 135 | + } |
| 136 | + } |
| 137 | + |
| 138 | + // Collect results in original order |
| 139 | + boolean hasFailures = false; |
| 140 | + for (int i = 0; i < reqs.size(); i++) { |
| 141 | + REQ req = reqs.get(i); |
| 142 | + CachingSupplier<REQ, REP> cs = suppliers.get(i); |
| 143 | + try { |
| 144 | + REP value = cs.apply(req); |
| 145 | + allResults.add(new RequestResult<>(req, value, null)); |
| 146 | + } catch (Throwable t) { |
| 147 | + hasFailures = true; |
| 148 | + allResults.add(new RequestResult<>(req, null, t)); |
| 149 | + } |
| 150 | + } |
| 151 | + |
| 152 | + if (hasFailures) { |
| 153 | + throw new BatchRequestException("One or more requests failed", allResults); |
| 154 | + } |
| 155 | + |
| 156 | + return allResults.stream().map(RequestResult::result).toList(); |
| 157 | + } |
| 158 | + |
| 159 | + /** |
| 160 | + * Abstract method to be implemented by subclasses to handle caching logic. |
| 161 | + * <p> |
| 162 | + * This method is responsible for determining whether a request result should be cached, |
| 163 | + * retrieving it from cache if available, or executing the supplier function if necessary. |
| 164 | + * </p> |
| 165 | + * |
| 166 | + * @param <REQ> The request type |
| 167 | + * @param <REP> The response type |
| 168 | + * @param req The request object |
| 169 | + * @param supplier The function that provides the response |
| 170 | + * @return A caching supplier that handles caching logic for the request |
| 171 | + */ |
| 172 | + protected abstract <REQ extends Request<?>, REP extends Result<REQ>> CachingSupplier<REQ, REP> doCache( |
| 173 | + REQ req, Function<REQ, REP> supplier); |
| 174 | + |
| 175 | + @SuppressWarnings("unchecked") |
| 176 | + protected static <T extends Throwable> void uncheckedThrow(Throwable t) throws T { |
| 177 | + throw (T) t; // rely on vacuous cast |
| 178 | + } |
| 179 | +} |
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