From 717690cb71f0a047a37fafa7219682b5bf3b5eca Mon Sep 17 00:00:00 2001
From: Hannes Wellmann <wellmann.hannes1@gmx.net>
Date: Sat, 2 Sep 2023 15:18:22 +0200
Subject: [PATCH] Add new method IQueryResult.stream()

This improves the interoperability of IQueryResult and the Java's modern
Stream-API.
---
 .../.settings/.api_filters                      |  8 ++++++++
 .../equinox/p2/query/CollectionResult.java      |  6 ++++++
 .../org/eclipse/equinox/p2/query/Collector.java |  6 ++++++
 .../eclipse/equinox/p2/query/IQueryResult.java  | 17 +++++++++++++++++
 4 files changed, 37 insertions(+)

diff --git a/bundles/org.eclipse.equinox.p2.metadata/.settings/.api_filters b/bundles/org.eclipse.equinox.p2.metadata/.settings/.api_filters
index d8f48e5c23..6b7f3a23f8 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/.settings/.api_filters
+++ b/bundles/org.eclipse.equinox.p2.metadata/.settings/.api_filters
@@ -8,4 +8,12 @@
             </message_arguments>
         </filter>
     </resource>
+    <resource path="src/org/eclipse/equinox/p2/query/IQueryResult.java" type="org.eclipse.equinox.p2.query.IQueryResult">
+        <filter id="404000815">
+            <message_arguments>
+                <message_argument value="org.eclipse.equinox.p2.query.IQueryResult"/>
+                <message_argument value="stream()"/>
+            </message_arguments>
+        </filter>
+    </resource>
 </component>
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CollectionResult.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CollectionResult.java
index 483efac5d1..73ca211d4c 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CollectionResult.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CollectionResult.java
@@ -18,6 +18,7 @@
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.stream.Stream;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.equinox.internal.p2.metadata.expression.QueryResult;
 
@@ -68,4 +69,9 @@ public Set<T> toUnmodifiableSet() {
 	public String toString() {
 		return collection.toString();
 	}
+
+	@Override
+	public Stream<T> stream() {
+		return collection.stream();
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/Collector.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/Collector.java
index 25373f5bc9..6aa5f6658b 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/Collector.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/Collector.java
@@ -19,6 +19,7 @@
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.stream.Stream;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.equinox.internal.p2.metadata.Messages;
@@ -178,4 +179,9 @@ public Set<T> toUnmodifiableSet() {
 		}
 		return Collections.unmodifiableSet(collected);
 	}
+
+	@Override
+	public Stream<T> stream() {
+		return collected == null ? Stream.empty() : collected.stream();
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/IQueryResult.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/IQueryResult.java
index 3bb03e7a63..b2b2dd4f3f 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/IQueryResult.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/IQueryResult.java
@@ -14,8 +14,11 @@
 ******************************************************************************/
 package org.eclipse.equinox.p2.query;
 
+import java.util.Collection;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 /**
  * An IQueryResult represents the results of a query.
@@ -63,4 +66,18 @@ public interface IQueryResult<T> extends IQueryable<T>, Iterable<T> {
 	 * @return A Set backed by this query result.
 	 */
 	Set<T> toUnmodifiableSet();
+
+	/**
+	 * Returns a sequential {@code Stream} of the collected objects.
+	 * 
+	 * @implSpec The default implementation creates a sequential {@code Stream} from
+	 *           this query-results {@code Spliterator}. Implementations backed by a
+	 *           {@code Collection} should override this method and call
+	 *           {@link Collection#stream()}.
+	 * @since 2.7
+	 */
+	default Stream<T> stream() {
+		return StreamSupport.stream(spliterator(), false);
+	}
+
 }