1 files changed, 90 insertions, 0 deletions
diff --git a/bundles/org.eclipse.osgi/felix/src/org/apache/felix/resolver/util/CandidateSelector.java b/bundles/org.eclipse.osgi/felix/src/org/apache/felix/resolver/util/CandidateSelector.java
new file mode 100755
index 000000000..0014bf037
--- /dev/null
+++ b/bundles/org.eclipse.osgi/felix/src/org/apache/felix/resolver/util/CandidateSelector.java
@@ -0,0 +1,90 @@
+/*
+ * 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.felix.resolver.util;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.osgi.resource.Capability;
+
+public class CandidateSelector {
+    private final AtomicBoolean isUnmodifiable;
+    protected final List<Capability> unmodifiable;
+    private int currentIndex = 0;
+
+    public CandidateSelector(List<Capability> candidates, AtomicBoolean isUnmodifiable) {
+        this.isUnmodifiable = isUnmodifiable;
+        this.unmodifiable = new ArrayList<Capability>(candidates);
+    }
+
+    protected CandidateSelector(CandidateSelector candidateSelector) {
+        this.isUnmodifiable = candidateSelector.isUnmodifiable;
+        this.unmodifiable = candidateSelector.unmodifiable;
+        this.currentIndex = candidateSelector.currentIndex;
+    }
+
+    public CandidateSelector copy() {
+        return new CandidateSelector(this);
+    }
+
+    public int getRemainingCandidateCount() {
+        return unmodifiable.size() - currentIndex;
+    }
+
+    public Capability getCurrentCandidate() {
+        return currentIndex < unmodifiable.size() ? unmodifiable.get(currentIndex) : null;
+    }
+
+    public List<Capability> getRemainingCandidates() {
+        return Collections.unmodifiableList(unmodifiable.subList(currentIndex, unmodifiable.size()));
+    }
+
+    public boolean isEmpty() {
+        return unmodifiable.size() <= currentIndex;
+    }
+
+    public Capability removeCurrentCandidate() {
+        Capability current = getCurrentCandidate();
+        if (current != null) {
+            currentIndex += 1;
+        }
+        return current;
+    }
+
+    public String toString() {
+        return getRemainingCandidates().toString();
+    }
+
+    public int remove(Capability cap) {
+        checkModifiable();
+        int index = unmodifiable.indexOf(cap);
+        if (index != -1) {
+            unmodifiable.remove(index);
+        }
+        return index;
+    }
+
+    protected void checkModifiable() {
+        if (isUnmodifiable.get()) {
+            throw new IllegalStateException("Trying to mutate after candidates have been prepared.");
+        }
+    }
+}