--- /dev/null
+/*******************************************************************************
+ * 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.collection;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.List;
+
+import org.eclipse.aether.RepositoryException;
+import org.eclipse.aether.artifact.Artifact;
+import org.eclipse.aether.graph.DependencyNode;
+import org.eclipse.aether.version.VersionConstraint;
+
+/**
+ * Thrown in case of an unsolvable conflict between different version constraints for a dependency.
+ */
+public class UnsolvableVersionConflictException
+ extends RepositoryException
+{
+
+ private final transient Collection<String> versions;
+
+ private final transient Collection<? extends List<? extends DependencyNode>> paths;
+
+ /**
+ * Creates a new exception with the specified paths to conflicting nodes in the dependency graph.
+ *
+ * @param paths The paths to the dependency nodes that participate in the version conflict, may be {@code null}.
+ */
+ public UnsolvableVersionConflictException( Collection<? extends List<? extends DependencyNode>> paths )
+ {
+ super( "Could not resolve version conflict among " + toPaths( paths ) );
+ if ( paths == null )
+ {
+ this.paths = Collections.emptyList();
+ this.versions = Collections.emptyList();
+ }
+ else
+ {
+ this.paths = paths;
+ this.versions = new LinkedHashSet<String>();
+ for ( List<? extends DependencyNode> path : paths )
+ {
+ VersionConstraint constraint = path.get( path.size() - 1 ).getVersionConstraint();
+ if ( constraint != null && constraint.getRange() != null )
+ {
+ versions.add( constraint.toString() );
+ }
+ }
+ }
+ }
+
+ private static String toPaths( Collection<? extends List<? extends DependencyNode>> paths )
+ {
+ String result = "";
+
+ if ( paths != null )
+ {
+ Collection<String> strings = new LinkedHashSet<String>();
+
+ for ( List<? extends DependencyNode> path : paths )
+ {
+ strings.add( toPath( path ) );
+ }
+
+ result = strings.toString();
+ }
+
+ return result;
+ }
+
+ private static String toPath( List<? extends DependencyNode> path )
+ {
+ StringBuilder buffer = new StringBuilder( 256 );
+
+ for ( Iterator<? extends DependencyNode> it = path.iterator(); it.hasNext(); )
+ {
+ DependencyNode node = it.next();
+ if ( node.getDependency() == null )
+ {
+ continue;
+ }
+
+ Artifact artifact = node.getDependency().getArtifact();
+ buffer.append( artifact.getGroupId() );
+ buffer.append( ':' ).append( artifact.getArtifactId() );
+ buffer.append( ':' ).append( artifact.getExtension() );
+ if ( artifact.getClassifier().length() > 0 )
+ {
+ buffer.append( ':' ).append( artifact.getClassifier() );
+ }
+ buffer.append( ':' ).append( node.getVersionConstraint() );
+
+ if ( it.hasNext() )
+ {
+ buffer.append( " -> " );
+ }
+ }
+
+ return buffer.toString();
+ }
+
+ /**
+ * Gets the paths leading to the conflicting dependencies.
+ *
+ * @return The (read-only) paths leading to the conflicting dependencies, never {@code null}.
+ */
+ public Collection<? extends List<? extends DependencyNode>> getPaths()
+ {
+ return paths;
+ }
+
+ /**
+ * Gets the conflicting version constraints of the dependency.
+ *
+ * @return The (read-only) conflicting version constraints, never {@code null}.
+ */
+ public Collection<String> getVersions()
+ {
+ return versions;
+ }
+
+}