Merge tag 'v2.3.20' into testing

[gpl/argeo-jcr.git] / org.argeo.slc.repo / src / org / eclipse / aether / RepositoryCache.java

diff --git a/org.argeo.slc.repo/src/org/eclipse/aether/RepositoryCache.java b/org.argeo.slc.repo/src/org/eclipse/aether/RepositoryCache.java
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+++ b/org.argeo.slc.repo/src/org/eclipse/aether/RepositoryCache.java
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+/*******************************************************************************
+ * Copyright (c) 2010, 2014 Sonatype, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Sonatype, Inc. - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.aether;
+
+/**
+ * Caches auxiliary data used during repository access like already processed metadata. The data in the cache is meant
+ * for exclusive consumption by the repository system and is opaque to the cache implementation. <strong>Note:</strong>
+ * Actual cache implementations must be thread-safe.
+ * 
+ * @see RepositorySystemSession#getCache()
+ */
+public interface RepositoryCache
+{
+
+    /**
+     * Puts the specified data into the cache. It is entirely up to the cache implementation how long this data will be
+     * kept before being purged, i.e. callers must not make any assumptions about the lifetime of cached data.
+     * <p>
+     * <em>Warning:</em> The cache will directly save the provided reference. If the cached data is mutable, i.e. could
+     * be modified after being put into the cache, the caller is responsible for creating a copy of the original data
+     * and store the copy in the cache.
+     * 
+     * @param session The repository session during which the cache is accessed, must not be {@code null}.
+     * @param key The key to use for lookup of the data, must not be {@code null}.
+     * @param data The data to store in the cache, may be {@code null}.
+     */
+    void put( RepositorySystemSession session, Object key, Object data );
+
+    /**
+     * Gets the specified data from the cache.
+     * <p>
+     * <em>Warning:</em> The cache will directly return the saved reference. If the cached data is to be modified after
+     * its retrieval, the caller is responsible to create a copy of the returned data and use this instead of the cache
+     * record.
+     * 
+     * @param session The repository session during which the cache is accessed, must not be {@code null}.
+     * @param key The key to use for lookup of the data, must not be {@code null}.
+     * @return The requested data or {@code null} if none was present in the cache.
+     */
+    Object get( RepositorySystemSession session, Object key );
+
+}