/*
 * Copyright 2012 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.repositories.resolver;

import org.apache.ivy.core.module.descriptor.Artifact;
import org.gradle.api.internal.resource.ResourceException;
import org.gradle.api.internal.resource.ResourceNotFoundException;

import java.util.HashSet;
import java.util.Set;

public class DefaultVersionList extends AbstractVersionList {
    private final Set<ListedVersion> versions = new HashSet<ListedVersion>();

    public DefaultVersionList() {
    }

    protected void add(ListedVersion newVersion) {
        // Only add when unique
        for (ListedVersion existingVersion : versions) {
            if (existingVersion.getVersion().equals(newVersion.getVersion())) {
                return;
            }
        }
        versions.add(newVersion);
    }

    public void visit(ResourcePattern pattern, Artifact artifact) throws ResourceNotFoundException, ResourceException {
        throw new UnsupportedOperationException();
    }

    public Set<ListedVersion> getVersions() {
        return versions;
    }
}

@@ -879,19 +879,67 @@
 til.Hash
-Set
+Map;%0Aimport java.util.HashSet;%0Aimport java.util.Map
 ;%0Aimport
@@ -1035,20 +1035,28 @@
 e final 
-Set%3C
+Map%3CString, 
 ListedVe
@@ -1081,20 +1081,28 @@
 new Hash
-Set%3C
+Map%3CString, 
 ListedVe
@@ -1216,140 +1216,32 @@
     
-// Only add when unique%0A        for (ListedVersion existingVersion : versions) %7B%0A            if (existingVersion.getVersion().equals
+if (versions.containsKey
 (new
@@ -1281,20 +1281,16 @@
     
- 
-   
 return;%0A
     
@@ -1289,22 +1289,8 @@
 rn;%0A
-            %7D%0A
     
@@ -1312,20 +1312,45 @@
 ersions.
-add(
+put(newVersion.getVersion(), 
 newVersi
@@ -1600,24 +1600,61 @@
  return 
-versions
+new HashSet%3CListedVersion%3E(versions.values())
 ;%0A    %7D%0A

Use a map to detect duplicate versions