Maven Central search results should be cached #263

Fixes: #263

lemminx-maven/src/main/java/org/eclipse/lemminx/extensions/maven/searcher/RemoteCentralRepositorySearcher.java

@@ -14,6 +14,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -56,8 +57,45 @@ public class RemoteCentralRepositorySearcher {
  public static boolean disableCentralSearch = Boolean
  .parseBoolean(System.getProperty(RemoteCentralRepositorySearcher.class.getName() + ".disableCentralSearch"));
 
+ public static long cacheDeprecationTimeoutMs = Long
+ .parseLong(System.getProperty(RemoteCentralRepositorySearcher.class.getName() + ".cacheDeprecationTimeoutMs", "-1"), 10);
+
  private OkHttpClient client = new OkHttpClient();
 
+ private static class Cache<K,V> {
+ private static long DEFAULT_DEPRECATION_TIMEOUT = 15*60*1000; 
+ private HashMap <Object,ValueDescriptor< V>> cache = new HashMap<>();
+ private long cacheDeprecationTimeout = DEFAULT_DEPRECATION_TIMEOUT;
+
+ public Cache(long deprecationTimeoutMs) {
+ cacheDeprecationTimeout = deprecationTimeoutMs != -1 ? 
+ deprecationTimeoutMs : DEFAULT_DEPRECATION_TIMEOUT;
+ }
+
+ class ValueDescriptor<T> {
+ T data;
+ long timestamp;
+ }
+
+ void put (K key, V value) {
+ ValueDescriptor<V> descriptor = new ValueDescriptor<>();
+ descriptor.data = value;
+ descriptor.timestamp = System.currentTimeMillis();
+ cache.put(key.toString(), descriptor);
+ }
+
+ V get(K key) {
+ ValueDescriptor<V> descriptor = cache.get(key.toString());
+ if (descriptor != null 
+ && (System.currentTimeMillis() - descriptor.timestamp 
+ < cacheDeprecationTimeout)) {
+ return descriptor.data;
+ }
+ return null;
+ }
+ }
+
+
  public RemoteCentralRepositorySearcher(MavenLemminxExtension lemminxMavenPlugin) {
  }
 
@@ -88,8 +126,14 @@ public Set<String> getPluginGroupIds(Dependency artifactToSearch) {
  return disableCentralSearch ? Collections.emptySet() : internalGetGroupIds(artifactToSearch, PACKAGING_TYPE_MAVEN_PLUGIN);
  }
 
+ private static Cache<Request, Collection<Artifact>> artifactsCache = new Cache<>(cacheDeprecationTimeoutMs);
  private Collection<Artifact> internalGetArtifacts(Dependency artifactToSearch, String packaging) {
  Request request = createArtifactIdsRequesty(artifactToSearch, packaging);
+ Collection<Artifact> cachedValue = artifactsCache.get(request);
+ if (cachedValue != null) {
+ return cachedValue;
+ }
+
  JsonObject responseBody = getResponseBody(request, artifactToSearch);
  if (responseBody == null || responseBody.get("numFound").getAsInt() <= 0 ) {
  return Collections.emptyList();
@@ -99,15 +143,23 @@ private Collection<Artifact> internalGetArtifacts(Dependency artifactToSearch, S
  responseBody.get("docs").getAsJsonArray().forEach(d -> {
  artifactInfos.add(toArtifactInfo(d.getAsJsonObject()));
  });
+
+ artifactsCache.put(request, artifactInfos);
  return artifactInfos;
  }
-
+
+ private static Cache<Request, Set<ArtifactVersion>> artifactVersionsCache = new Cache<>(cacheDeprecationTimeoutMs);
  private Set<ArtifactVersion> internalGetArtifactVersions(Dependency artifactToSearch, String packaging) {
  if (isEmpty(artifactToSearch.getArtifactId())) {
  return Collections.emptySet();
  }
 
  Request request = createArtifactVersionsRequest(artifactToSearch, packaging);
+ Set<ArtifactVersion> cachedValue = artifactVersionsCache.get(request);
+ if (cachedValue != null) {
+ return cachedValue;
+ }
+
  JsonObject responseBody = getResponseBody(request, artifactToSearch);
  if (responseBody == null || responseBody.get("numFound").getAsInt() <= 0 ) {
  return Collections.emptySet();
@@ -117,15 +169,23 @@ private Set<ArtifactVersion> internalGetArtifactVersions(Dependency artifactToSe
  responseBody.get("docs").getAsJsonArray().forEach(d -> {
  artifactVersions.add(new DefaultArtifactVersion(d.getAsJsonObject().get(VERSION).getAsString()));
  });
+
+ artifactVersionsCache.put(request, artifactVersions);
  return artifactVersions;
  }
 
+ private static Cache<Request, Set<String>> groupIdsCache = new Cache<>(cacheDeprecationTimeoutMs);
  private Set<String> internalGetGroupIds(Dependency artifactToSearch, String packaging) {
  if (isEmpty(artifactToSearch.getGroupId())) {
  return Collections.emptySet();
  }
 
  Request request = createGroupIdsRequest(artifactToSearch, packaging);
+ Set<String> cachedValue = groupIdsCache.get(request);
+ if (cachedValue != null) {
+ return cachedValue;
+ }
+
  JsonObject responseBody = getResponseBody(request, artifactToSearch);
  if (responseBody == null || responseBody.get("numFound").getAsInt() <= 0 ) {
  return Collections.emptySet();
@@ -135,6 +195,8 @@ private Set<String> internalGetGroupIds(Dependency artifactToSearch, String pack
  responseBody.get("docs").getAsJsonArray().forEach(d -> {
  artifactGroupIds.add(d.getAsJsonObject().get(GROUP_ID).getAsString());
  });
+
+ groupIdsCache.put(request, artifactGroupIds);
  return artifactGroupIds;
  }