Java tutorial
/* * Copyright 2017 the original author or authors. * * Licensed 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.gradle.api.internal.artifacts.ivyservice.resolveengine.excludes; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableSet; import com.google.common.collect.Iterators; import org.gradle.api.artifacts.ModuleIdentifier; import org.gradle.internal.Cast; import org.gradle.internal.component.model.IvyArtifactName; import java.util.Collection; import java.util.Iterator; import java.util.Set; final class ImmutableModuleExclusionSet implements Set<AbstractModuleExclusion> { private final Set<AbstractModuleExclusion> delegate; final AbstractModuleExclusion[] elements; private final int hashCode; // the following fields are used as optimizations, to avoid iterating on the whole set of exclusions private ImmutableSet<ModuleIdentifier> excludedModules; private ImmutableList<AbstractModuleExclusion> moduleExcludes; private ImmutableList<AbstractModuleExclusion> artifactExcludes; ImmutableModuleExclusionSet(ImmutableSet<AbstractModuleExclusion> delegate) { this.delegate = delegate; this.elements = delegate.toArray(new AbstractModuleExclusion[0]); this.hashCode = delegate.hashCode(); } private synchronized void precomputeCaches() { if (excludedModules != null) { return; } ImmutableSet.Builder<ModuleIdentifier> moduleIds = ImmutableSet.builder(); ImmutableList.Builder<AbstractModuleExclusion> modules = ImmutableList.builder(); ImmutableList.Builder<AbstractModuleExclusion> artifacts = ImmutableList.builder(); for (AbstractModuleExclusion exclusion : delegate) { if (exclusion instanceof ModuleIdExcludeSpec) { moduleIds.add(((ModuleIdExcludeSpec) exclusion).moduleId); } else { if (!exclusion.excludesNoModules()) { modules.add(exclusion); } if (exclusion.mayExcludeArtifacts()) { artifacts.add(exclusion); } } } excludedModules = moduleIds.build(); moduleExcludes = modules.build(); artifactExcludes = artifacts.build(); } @Override public int size() { return delegate.size(); } @Override public boolean isEmpty() { return delegate.isEmpty(); } @Override public boolean contains(Object o) { return delegate.contains(o); } @Override public Iterator<AbstractModuleExclusion> iterator() { return Iterators.forArray(elements); } /** * This method optimizes module exclusion lookup, based on empirical data showing that the set can be very large, but would contain mostly direct module exclusion nodes. So instead of always * iterating over all excluded modules, we can perform a fast lookup using a set of excluded modules first, then only iterate on the remaining exclusions. * * @param id the module to check * @return true if it's excluded */ boolean excludesModule(ModuleIdentifier id) { precomputeCaches(); if (excludedModules.contains(id)) { return true; } for (AbstractModuleExclusion excludeSpec : moduleExcludes) { if (excludeSpec.excludeModule(id)) { return true; } } return false; } boolean excludesArtifact(ModuleIdentifier module, IvyArtifactName artifact) { precomputeCaches(); for (AbstractModuleExclusion excludeSpec : artifactExcludes) { if (excludeSpec.excludeArtifact(module, artifact)) { return true; } } return false; } @Override public Object[] toArray() { return elements; } @Override public <T> T[] toArray(T[] a) { return Cast.uncheckedCast(elements); } @Override public boolean add(AbstractModuleExclusion abstractModuleExclusion) { throw new UnsupportedOperationException(); } @Override public boolean remove(Object o) { throw new UnsupportedOperationException(); } @Override public boolean containsAll(Collection<?> c) { return delegate.containsAll(c); } @Override public boolean addAll(Collection<? extends AbstractModuleExclusion> c) { throw new UnsupportedOperationException(); } @Override public boolean retainAll(Collection<?> c) { throw new UnsupportedOperationException(); } @Override public boolean removeAll(Collection<?> c) { throw new UnsupportedOperationException(); } @Override public void clear() { throw new UnsupportedOperationException(); } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } ImmutableModuleExclusionSet that = (ImmutableModuleExclusionSet) o; if (hashCode != that.hashCode) { return false; } return delegate.equals(that.delegate); } @Override public int hashCode() { return hashCode; } }