daniellansun commented on code in PR #3260: URL: https://github.com/apache/groovy/pull/3260#discussion_r4525497465
########## src/main/java/org/apache/groovy/vmplugin/internal/DefaultImportPackages.java: ########## @@ -0,0 +1,127 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.groovy.vmplugin.internal; + +import groovy.transform.Internal; + +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashSet; +import java.util.LinkedHashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; + +/** + * Orders default-import package prefixes by a caller-supplied precedence + * array. Iteration order of the returned sets is that array's order. + * Packages that are not in the array are dropped, so a {@code HashSet} + * walk cannot put a later package ahead of an earlier one. + * + * @since 7.0.0 + */ +@Internal +public final class DefaultImportPackages { + + private DefaultImportPackages() { + } + + /** + * Returns the members of {@code packages} that occur in {@code precedence}, + * iterated in {@code precedence} order. The result is unmodifiable. + * An empty result is {@link Collections#emptySet()}. A single match is + * {@link Collections#singleton(Object)}. + * + * @param packages packages discovered for one simple name; {@code null} is empty + * @param precedence package prefixes in the order they must be tried; {@code null} yields an empty set + * @return an immutable set in precedence order + */ + public static Set<String> ordered(final Collection<String> packages, final String[] precedence) { + if (packages == null || packages.isEmpty() || precedence == null || precedence.length == 0) { + return Collections.emptySet(); + } + List<String> matches = new ArrayList<>(Math.min(packages.size(), precedence.length)); + for (String candidate : precedence) { + if (packages.contains(candidate)) { + matches.add(candidate); + } + } + if (matches.isEmpty()) { + return Collections.emptySet(); + } + if (matches.size() == 1) { + return Collections.singleton(matches.get(0)); + } + return Collections.unmodifiableSet(new LinkedHashSet<>(matches)); Review Comment: `ordered()` now inserts into a `LinkedHashSet` while it walks `precedence`. Match order is insertion order, and there is no `ArrayList` to copy afterwards. The unmodifiable wrapper stays. `Collections.unmodifiableSet` does not copy; it only wraps that set. Callers publish the result: `ResolveVisitor` stores it in a `ConcurrentHashMap`, and until a later hit replaces the entry the same instance is the startup index (`Groovy12725` checks that with `assertSame`). A reader on another thread must not observe a set being edited, and the tests expect `add` to throw. An update replaces the map entry. An empty result is still `Collections.emptySet()`, and a single match is still `Collections.singleton`, which is already immutable. Package precedence and the replace-rather-than-mutate cache behaviour are unchanged. ########## src/main/java/org/apache/groovy/vmplugin/internal/DefaultImportPackages.java: ########## @@ -0,0 +1,127 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.groovy.vmplugin.internal; + +import groovy.transform.Internal; + +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashSet; +import java.util.LinkedHashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; + +/** + * Orders default-import package prefixes by a caller-supplied precedence + * array. Iteration order of the returned sets is that array's order. + * Packages that are not in the array are dropped, so a {@code HashSet} + * walk cannot put a later package ahead of an earlier one. + * + * @since 7.0.0 + */ +@Internal +public final class DefaultImportPackages { + + private DefaultImportPackages() { + } + + /** + * Returns the members of {@code packages} that occur in {@code precedence}, + * iterated in {@code precedence} order. The result is unmodifiable. + * An empty result is {@link Collections#emptySet()}. A single match is + * {@link Collections#singleton(Object)}. + * + * @param packages packages discovered for one simple name; {@code null} is empty + * @param precedence package prefixes in the order they must be tried; {@code null} yields an empty set + * @return an immutable set in precedence order + */ + public static Set<String> ordered(final Collection<String> packages, final String[] precedence) { + if (packages == null || packages.isEmpty() || precedence == null || precedence.length == 0) { + return Collections.emptySet(); + } + List<String> matches = new ArrayList<>(Math.min(packages.size(), precedence.length)); + for (String candidate : precedence) { + if (packages.contains(candidate)) { + matches.add(candidate); + } + } + if (matches.isEmpty()) { + return Collections.emptySet(); + } + if (matches.size() == 1) { + return Collections.singleton(matches.get(0)); + } + return Collections.unmodifiableSet(new LinkedHashSet<>(matches)); + } + + /** + * Returns {@code existing} when it already contains {@code packagePrefix}. + * Otherwise returns the precedence-ordered union. {@code packagePrefix} + * values absent from {@code precedence} are not added. + * + * @param existing the packages already recorded, or {@code null} + * @param packagePrefix the package to add + * @param precedence package prefixes in try-order + * @return an immutable set in precedence order, or {@code existing} when unchanged + */ + public static Set<String> including(final Set<String> existing, final String packagePrefix, final String[] precedence) { + if (existing != null && existing.contains(packagePrefix)) { + return existing; + } + Set<String> combined = new HashSet<>(existing == null ? 2 : existing.size() + 1); Review Comment: `including()` with a null `existing` only adds `packagePrefix`, so the temporary `HashSet` is created with capacity 1. -- This is an automated message from the Apache Git Service. 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