Reducing usage of guava libraries in dexlib2 and dexlib2/base (#25)

Part 1/n

12 files changed, 127 insertions, 60 deletions

diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/DexFileFactory.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/DexFileFactory.java
index 06698c8c..e7cefa17 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/DexFileFactory.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/DexFileFactory.java
@@ -30,14 +30,12 @@
 
 package com.android.tools.smali.dexlib2;
 
+import static java.util.Collections.unmodifiableList;
+
 import com.android.tools.smali.dexlib2.iface.DexFile;
 import com.android.tools.smali.dexlib2.iface.MultiDexContainer;
 import com.android.tools.smali.dexlib2.iface.MultiDexContainer.DexEntry;
-import com.google.common.base.Joiner;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Lists;
-import com.google.common.io.ByteStreams;
-import com.google.common.io.Files;
+
 import com.android.tools.smali.dexlib2.dexbacked.DexBackedDexFile;
 import com.android.tools.smali.dexlib2.dexbacked.DexBackedDexFile.NotADexFile;
 import com.android.tools.smali.dexlib2.dexbacked.DexBackedOdexFile;
@@ -48,6 +46,7 @@ import com.android.tools.smali.dexlib2.dexbacked.ZipDexContainer;
 import com.android.tools.smali.dexlib2.dexbacked.ZipDexContainer.NotAZipFileException;
 import com.android.tools.smali.dexlib2.writer.pool.DexPool;
 import com.android.tools.smali.util.ExceptionWithContext;
+import com.android.tools.smali.util.StringUtils;
 
 import java.io.BufferedInputStream;
 import java.io.File;
@@ -57,6 +56,8 @@ import java.io.IOException;
 import java.io.InputStream;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+
+import java.util.ArrayList;
 import java.util.List;
 
 public final class DexFileFactory {
@@ -395,10 +396,10 @@ public final class DexFileFactory {
             }
 
             // find all full and partial matches
-            List<String> fullMatches = Lists.newArrayList();
-            List<MultiDexContainer.DexEntry<? extends DexBackedDexFile>> fullEntries = Lists.newArrayList();
-            List<String> partialMatches = Lists.newArrayList();
-            List<MultiDexContainer.DexEntry<? extends DexBackedDexFile>> partialEntries = Lists.newArrayList();
+            List<String> fullMatches = new ArrayList<>();
+            List<MultiDexContainer.DexEntry<? extends DexBackedDexFile>> fullEntries = new ArrayList<>();
+            List<String> partialMatches = new ArrayList<>();
+            List<MultiDexContainer.DexEntry<? extends DexBackedDexFile>> partialEntries = new ArrayList<>();
             for (String entry: dexContainer.getDexEntryNames()) {
                 if (fullEntryMatch(entry, targetEntry)) {
                     // We want to grab all full matches, regardless of whether they're actually a dex file.
@@ -430,7 +431,8 @@ public final class DexFileFactory {
                 // only by an initial path separator. e.g. "/blah/blah.dex" and "blah/blah.dex"
                 throw new MultipleMatchingDexEntriesException(String.format(
                         "Multiple entries in %s match %s: %s", filename, targetEntry,
-                        Joiner.on(", ").join(fullMatches)));
+                        StringUtils.join(fullMatches, ", ")
+                        ));
             }
 
             if (partialEntries.size() == 0) {
@@ -440,7 +442,8 @@ public final class DexFileFactory {
             if (partialEntries.size() > 1) {
                 throw new MultipleMatchingDexEntriesException(String.format(
                         "Multiple dex entries in %s match %s: %s", filename, targetEntry,
-                        Joiner.on(", ").join(partialMatches)));
+                        StringUtils.join(partialMatches, ", ")
+                        ));
             }
             return partialEntries.get(0);
         }
@@ -456,7 +459,7 @@ public final class DexFileFactory {
         }
 
         @Nonnull @Override public List<String> getDexEntryNames() {
-            return ImmutableList.of(entryName);
+            return unmodifiableList(List.of(entryName));
         }
 
         @Nullable @Override public DexEntry<DexBackedDexFile> getEntry(@Nonnull String entryName) {
@@ -494,7 +497,7 @@ public final class DexFileFactory {
 
         public FilenameVdexProvider(File oatFile) {
             File oatParent = oatFile.getAbsoluteFile().getParentFile();
-            String baseName = Files.getNameWithoutExtension(oatFile.getAbsolutePath());
+            String baseName = getNameWithoutExtension(oatFile.getAbsolutePath());
             vdexFile = new File(oatParent, baseName + ".vdex");
         }
 
@@ -515,7 +518,10 @@ public final class DexFileFactory {
 
                 if (candidateFile.exists()) {
                     try {
-                        buf = ByteStreams.toByteArray(new FileInputStream(candidateFile));
+                        FileInputStream fis = new FileInputStream(candidateFile);
+                        int fileSize = fis.available();
+                        buf = new byte[fileSize];
+                        fis.read(buf);
                     } catch (FileNotFoundException e) {
                         buf = null;
                     } catch (IOException ex) {
@@ -527,5 +533,11 @@ public final class DexFileFactory {
 
             return buf;
         }
+
+        public static String getNameWithoutExtension(String file) {
+            String fileName = new File(file).getName();
+            int dotIndex = fileName.lastIndexOf('.');
+            return (dotIndex == -1) ? fileName : fileName.substring(0, dotIndex);
+          }
     }
 }
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/HiddenApiRestriction.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/HiddenApiRestriction.java
index 2f1683a0..f1e697d5 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/HiddenApiRestriction.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/HiddenApiRestriction.java
@@ -30,10 +30,10 @@
 
 package com.android.tools.smali.dexlib2;
 
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ImmutableSet.Builder;
+import static java.util.Collections.unmodifiableSet;
 
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import java.util.StringJoiner;
@@ -107,19 +107,20 @@ public enum HiddenApiRestriction {
 
     public static Set<HiddenApiRestriction> getAllFlags(int value) {
         HiddenApiRestriction normalRestriction = hiddenApiFlags[value & HIDDENAPI_FLAG_MASK];
+        HashSet restrictionSet = new HashSet<HiddenApiRestriction>();
 
         int domainSpecificPart = (value & ~HIDDENAPI_FLAG_MASK);
         if (domainSpecificPart == 0) {
-            return ImmutableSet.of(normalRestriction);
+            restrictionSet.add(normalRestriction);
+            return unmodifiableSet(restrictionSet);
         }
-        Builder<HiddenApiRestriction> builder = ImmutableSet.builder();
-        builder.add(normalRestriction);
+        restrictionSet.add(normalRestriction);
         for (HiddenApiRestriction domainSpecificApiFlag : domainSpecificApiFlags) {
             if (domainSpecificApiFlag.isSet(value)) {
-                builder.add(domainSpecificApiFlag);
+                restrictionSet.add(domainSpecificApiFlag);
             }
         }
-        return builder.build();
+        return unmodifiableSet(restrictionSet);
     }
 
     public static String formatHiddenRestrictions(int value) {
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/MethodHandleType.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/MethodHandleType.java
index 27a6b611..6ba1726b 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/MethodHandleType.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/MethodHandleType.java
@@ -30,8 +30,11 @@
 
 package com.android.tools.smali.dexlib2;
 
-import com.google.common.collect.BiMap;
-import com.google.common.collect.ImmutableBiMap;
+import static java.util.Collections.unmodifiableMap;
+
+import java.util.HashMap;
+import java.util.Map;
+
 import com.android.tools.smali.util.ExceptionWithContext;
 
 import javax.annotation.Nonnull;
@@ -47,17 +50,26 @@ public class MethodHandleType {
     public static final int INVOKE_DIRECT = 7;
     public static final int INVOKE_INTERFACE = 8;
 
-    private static final BiMap<Integer, String> methodHandleTypeNames = new ImmutableBiMap.Builder<Integer, String>()
-            .put(STATIC_PUT, "static-put")
-            .put(STATIC_GET, "static-get")
-            .put(INSTANCE_PUT, "instance-put")
-            .put(INSTANCE_GET, "instance-get")
-            .put(INVOKE_STATIC, "invoke-static")
-            .put(INVOKE_INSTANCE, "invoke-instance")
-            .put(INVOKE_CONSTRUCTOR, "invoke-constructor")
-            .put(INVOKE_DIRECT, "invoke-direct")
-            .put(INVOKE_INTERFACE, "invoke-interface")
-            .build();
+    private static final Map<Integer, String> methodHandleTypeNames = unmodifiableMap(Map.of(
+            STATIC_PUT, "static-put",
+            STATIC_GET, "static-get",
+            INSTANCE_PUT, "instance-put",
+            INSTANCE_GET, "instance-get",
+            INVOKE_STATIC, "invoke-static",
+            INVOKE_INSTANCE, "invoke-instance",
+            INVOKE_CONSTRUCTOR, "invoke-constructor",
+            INVOKE_DIRECT, "invoke-direct",
+            INVOKE_INTERFACE, "invoke-interface"));
+
+    private static final Map<String, Integer> inverse = getInverse();
+
+    private static Map<String, Integer> getInverse() {
+        HashMap<String, Integer> namesToTypes = new HashMap<>();
+        for (Map.Entry<Integer, String> entry : methodHandleTypeNames.entrySet()) {
+            namesToTypes.put(entry.getValue(), entry.getKey());
+        }
+        return unmodifiableMap(namesToTypes);
+    }
 
     @Nonnull public static String toString(int methodHandleType) {
         String val = methodHandleTypeNames.get(methodHandleType);
@@ -68,7 +80,7 @@ public class MethodHandleType {
     }
 
     public static int getMethodHandleType(String methodHandleType) {
-        Integer ret = methodHandleTypeNames.inverse().get(methodHandleType);
+        Integer ret = inverse.get(methodHandleType);
         if (ret == null) {
             throw new ExceptionWithContext("Invalid method handle type: %s", methodHandleType);
         }
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/Opcodes.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/Opcodes.java
index 5a88b0db..176c5175 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/Opcodes.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/Opcodes.java
@@ -30,7 +30,6 @@
 
 package com.android.tools.smali.dexlib2;
 
-import com.google.common.collect.Maps;
 import com.google.common.collect.RangeMap;
 
 import javax.annotation.Nonnull;
@@ -94,7 +93,7 @@ public class Opcodes {
         }
 
         opcodeValues = new EnumMap<Opcode, Short>(Opcode.class);
-        opcodesByName = Maps.newHashMap();
+        opcodesByName = new HashMap<>();
 
         int version;
         if (isArt()) {
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/VerificationError.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/VerificationError.java
index d4315886..f7282d7c 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/VerificationError.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/VerificationError.java
@@ -30,7 +30,6 @@
 
 package com.android.tools.smali.dexlib2;
 
-import com.google.common.collect.Maps;
 import com.android.tools.smali.util.ExceptionWithContext;
 
 import javax.annotation.Nullable;
@@ -47,7 +46,7 @@ public class VerificationError {
     public static final int CLASS_CHANGE_ERROR = 8;
     public static final int INSTANTIATION_ERROR = 9;
 
-    private static final HashMap<String, Integer> verificationErrorNames = Maps.newHashMap();
+    private static final HashMap<String, Integer> verificationErrorNames = new HashMap<>();
 
     static {
         verificationErrorNames.put("generic-error", GENERIC);
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseAnnotation.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseAnnotation.java
index 5dd2e603..f271c429 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseAnnotation.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseAnnotation.java
@@ -31,7 +31,6 @@
 package com.android.tools.smali.dexlib2.base;
 
 import com.android.tools.smali.dexlib2.iface.Annotation;
-import com.google.common.primitives.Ints;
 import com.android.tools.smali.util.CollectionUtils;
 
 import java.util.Comparator;
@@ -57,7 +56,7 @@ public abstract class BaseAnnotation implements Annotation {
 
     @Override
     public int compareTo(Annotation o) {
-        int res = Ints.compare(getVisibility(), o.getVisibility());
+        int res = Integer.compare(getVisibility(), o.getVisibility());
         if (res != 0) return res;
         res = getType().compareTo(o.getType());
         if (res != 0) return res;
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseExceptionHandler.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseExceptionHandler.java
index 32ca007f..5f6d098a 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseExceptionHandler.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/BaseExceptionHandler.java
@@ -31,14 +31,13 @@
 package com.android.tools.smali.dexlib2.base;
 
 import com.android.tools.smali.dexlib2.iface.ExceptionHandler;
-import com.google.common.base.Objects;
-import com.google.common.primitives.Ints;
 import com.android.tools.smali.dexlib2.base.reference.BaseTypeReference;
 import com.android.tools.smali.dexlib2.iface.reference.TypeReference;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.util.Comparator;
+import java.util.Objects;
 
 public abstract class BaseExceptionHandler implements ExceptionHandler {
     @Nullable @Override public TypeReference getExceptionTypeReference() {
@@ -65,7 +64,7 @@ public abstract class BaseExceptionHandler implements ExceptionHandler {
     public boolean equals(@Nullable Object o) {
         if (o instanceof ExceptionHandler) {
             ExceptionHandler other = (ExceptionHandler)o;
-            return Objects.equal(getExceptionType(), other.getExceptionType()) &&
+            return Objects.equals(getExceptionType(), other.getExceptionType()) &&
                    (getHandlerCodeAddress() == other.getHandlerCodeAddress());
         }
         return false;
@@ -87,7 +86,7 @@ public abstract class BaseExceptionHandler implements ExceptionHandler {
             res = exceptionType.compareTo(o.getExceptionType());
             if (res != 0) return res;
         }
-        return Ints.compare(getHandlerCodeAddress(), o.getHandlerCodeAddress());
+        return Integer.compare(getHandlerCodeAddress(), o.getHandlerCodeAddress());
     }
 
 
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodHandleReference.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodHandleReference.java
index e14b23a4..f2d4e842 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodHandleReference.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodHandleReference.java
@@ -34,7 +34,6 @@ import com.android.tools.smali.dexlib2.iface.reference.FieldReference;
 import com.android.tools.smali.dexlib2.iface.reference.MethodHandleReference;
 import com.android.tools.smali.dexlib2.iface.reference.MethodReference;
 import com.android.tools.smali.dexlib2.iface.reference.Reference;
-import com.google.common.primitives.Ints;
 import com.android.tools.smali.dexlib2.formatter.DexFormatter;
 
 import javax.annotation.Nonnull;
@@ -60,7 +59,7 @@ public abstract class BaseMethodHandleReference extends BaseReference implements
 
     @Override
     public int compareTo(@Nonnull MethodHandleReference o) {
-        int res = Ints.compare(getMethodHandleType(), o.getMethodHandleType());
+        int res = Integer.compare(getMethodHandleType(), o.getMethodHandleType());
         if (res != 0) return res;
 
         Reference reference = getMemberReference();
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodProtoReference.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodProtoReference.java
index 4a1309ef..b43e6647 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodProtoReference.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodProtoReference.java
@@ -33,7 +33,6 @@ package com.android.tools.smali.dexlib2.base.reference;
 import com.android.tools.smali.dexlib2.iface.reference.MethodProtoReference;
 import com.android.tools.smali.util.CharSequenceUtils;
 import com.android.tools.smali.util.CollectionUtils;
-import com.google.common.collect.Ordering;
 import com.android.tools.smali.dexlib2.formatter.DexFormatter;
 
 import javax.annotation.Nonnull;
@@ -62,7 +61,8 @@ public abstract class BaseMethodProtoReference extends BaseReference implements
     public int compareTo(@Nonnull MethodProtoReference o) {
         int res = getReturnType().compareTo(o.getReturnType());
         if (res != 0) return res;
-        return CollectionUtils.compareAsIterable(Ordering.usingToString(), getParameterTypes(), o.getParameterTypes());
+        return CollectionUtils.compareAsIterable(
+            CollectionUtils.usingToStringOrdering(), getParameterTypes(), o.getParameterTypes());
     }
 
     @Override public String toString() {
diff --git a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodReference.java b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodReference.java
index 079b073f..5fda22a3 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodReference.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/dexlib2/base/reference/BaseMethodReference.java
@@ -33,7 +33,6 @@ package com.android.tools.smali.dexlib2.base.reference;
 import com.android.tools.smali.dexlib2.iface.reference.MethodReference;
 import com.android.tools.smali.util.CharSequenceUtils;
 import com.android.tools.smali.util.CollectionUtils;
-import com.google.common.collect.Ordering;
 import com.android.tools.smali.dexlib2.formatter.DexFormatter;
 
 import javax.annotation.Nonnull;
@@ -68,7 +67,8 @@ public abstract class BaseMethodReference extends BaseReference implements Metho
         if (res != 0) return res;
         res = getReturnType().compareTo(o.getReturnType());
         if (res != 0) return res;
-        return CollectionUtils.compareAsIterable(Ordering.usingToString(), getParameterTypes(), o.getParameterTypes());
+        return CollectionUtils.compareAsIterable(
+            CollectionUtils.usingToStringOrdering(), getParameterTypes(), o.getParameterTypes());
     }
 
     @Override public String toString() {
diff --git a/dexlib2/src/main/java/com/android/tools/smali/util/CollectionUtils.java b/dexlib2/src/main/java/com/android/tools/smali/util/CollectionUtils.java
index 75bf7f9c..2fe222af 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/util/CollectionUtils.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/util/CollectionUtils.java
@@ -32,13 +32,13 @@ package com.android.tools.smali.util;
 
 import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableSortedSet;
-import com.google.common.collect.Ordering;
-import com.google.common.primitives.Ints;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.SortedSet;
+
 import javax.annotation.Nonnull;
 
 public class CollectionUtils {
@@ -64,7 +64,7 @@ public class CollectionUtils {
 
     public static <T extends Comparable<? super T>> int compareAsList(@Nonnull Collection<? extends T> list1,
                                                                       @Nonnull Collection<? extends T> list2) {
-        int res = Ints.compare(list1.size(), list2.size());
+        int res = Integer.compare(list1.size(), list2.size());
         if (res != 0) return res;
         Iterator<? extends T> elements2 = list2.iterator();
         for (T element1: list1) {
@@ -114,7 +114,7 @@ public class CollectionUtils {
     public static <T> int compareAsList(@Nonnull Comparator<? super T> elementComparator,
                                         @Nonnull Collection<? extends T> list1,
                                         @Nonnull Collection<? extends T> list2) {
-        int res = Ints.compare(list1.size(), list2.size());
+        int res = Integer.compare(list1.size(), list2.size());
         if (res != 0) return res;
         Iterator<? extends T> elements2 = list2.iterator();
         for (T element1: list1) {
@@ -139,7 +139,7 @@ public class CollectionUtils {
         if (it instanceof SortedSet) {
             SortedSet<? extends T> sortedSet = (SortedSet<? extends T>)it;
             Comparator<?> comparator = sortedSet.comparator();
-            return (comparator == null) || comparator.equals(Ordering.natural());
+            return (comparator == null) || comparator.equals(NaturalOrdering.INSTANCE);
         }
         return false;
     }
@@ -150,7 +150,7 @@ public class CollectionUtils {
             SortedSet<? extends T> sortedSet = (SortedSet<? extends T>)it;
             Comparator<?> comparator = sortedSet.comparator();
             if (comparator == null) {
-                return elementComparator.equals(Ordering.natural());
+                return elementComparator.equals(NaturalOrdering.INSTANCE);
             }
             return elementComparator.equals(comparator);
         }
@@ -162,7 +162,8 @@ public class CollectionUtils {
         if (isNaturalSortedSet(collection)) {
             return (SortedSet<? extends T>)collection;
         }
-        return ImmutableSortedSet.copyOf(collection);
+        SortedSet<? extends T> sortedSet = ArraySortedSet.of(NaturalOrdering.INSTANCE, collection.toArray());
+        return Collections.unmodifiableSortedSet(sortedSet);
     }
 
     @Nonnull
@@ -175,6 +176,7 @@ public class CollectionUtils {
                 return sortedSet;
             }
         }
+
         return ImmutableSortedSet.copyOf(elementComparator, collection);
     }
 
@@ -191,7 +193,7 @@ public class CollectionUtils {
 
     public static <T extends Comparable<T>> int compareAsSet(@Nonnull Collection<? extends T> set1,
                                                              @Nonnull Collection<? extends T> set2) {
-        int res = Ints.compare(set1.size(), set2.size());
+        int res = Integer.compare(set1.size(), set2.size());
         if (res != 0) return res;
 
         SortedSet<? extends T> sortedSet1 = toNaturalSortedSet(set1);
@@ -208,7 +210,7 @@ public class CollectionUtils {
     public static <T> int compareAsSet(@Nonnull Comparator<? super T> elementComparator,
                                        @Nonnull Collection<? extends T> list1,
                                        @Nonnull Collection<? extends T> list2) {
-        int res = Ints.compare(list1.size(), list2.size());
+        int res = Integer.compare(list1.size(), list2.size());
         if (res != 0) return res;
 
         SortedSet<? extends T> set1 = toSortedSet(elementComparator, list1);
@@ -221,4 +223,34 @@ public class CollectionUtils {
         }
         return 0;
     }
+
+    public static <T> Comparator<? super T> usingToStringOrdering() {
+        return UsingToStringOrdering.INSTANCE;
+    }
+
+    public static <T> Comparator<? super T> naturalOrdering() {
+        return NaturalOrdering.INSTANCE;
+    }
+
+    public final static class UsingToStringOrdering<T extends Object> implements Comparator<T> {
+        static final UsingToStringOrdering INSTANCE = new UsingToStringOrdering();
+
+        @Override
+        public int compare(Object left, Object right) {
+            return left.toString().compareTo(right.toString());
+        }
+
+        private UsingToStringOrdering() {}
+    }
+
+    public final static class NaturalOrdering<T extends Comparable<? super T>> implements Comparator<T> {
+        static final NaturalOrdering INSTANCE = new NaturalOrdering();
+
+        @Override
+        public int compare(T left, T right) {
+            return left.compareTo(right);
+        }
+
+        private NaturalOrdering() {}
+    }
 }
diff --git a/dexlib2/src/main/java/com/android/tools/smali/util/StringUtils.java b/dexlib2/src/main/java/com/android/tools/smali/util/StringUtils.java
index 4c567d17..730caa8f 100644
--- a/dexlib2/src/main/java/com/android/tools/smali/util/StringUtils.java
+++ b/dexlib2/src/main/java/com/android/tools/smali/util/StringUtils.java
@@ -33,6 +33,8 @@ package com.android.tools.smali.util;
 import com.android.tools.smali.dexlib2.formatter.DexFormattedWriter;
 import java.io.IOException;
 import java.io.Writer;
+import java.util.Iterator;
+import java.util.List;
 
 public class StringUtils {
 
@@ -122,4 +124,17 @@ public class StringUtils {
 
         return sb.toString();
     }
+
+    public static String join(List<? extends Object> parts, String separator) {
+        StringBuilder builder = new StringBuilder();
+        Iterator<? extends Object> it = parts.iterator();
+        if (it.hasNext()) {
+            builder.append(it.hasNext());
+        }
+        while (it.hasNext()) {
+            builder.append(separator);
+            builder.append(it.next());
+        }
+        return builder.toString();
+    }
 }