Add sorted interface and immutable implementations

util/src/main/java/org/jf/util/ArraySortedSet.java

@@ -0,0 +1,198 @@
+/*
+ * Copyright 2012, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.jf.util;
+
+import com.google.common.collect.Iterators;
+
+import javax.annotation.Nonnull;
+import java.util.*;
+
+public class ArraySortedSet<T> implements SortedSet<T> {
+    @Nonnull private final Comparator<? super T> comparator;
+    @Nonnull private final Object[] arr;
+
+    private ArraySortedSet(@Nonnull Comparator<? super T> comparator, @Nonnull T[] arr) {
+        // we assume arr is already sorted by comparator, and all entries are unique
+        this.comparator = comparator;
+        this.arr = arr;
+    }
+
+    public static <T> ArraySortedSet<T> of(@Nonnull Comparator<? super T> comparator, @Nonnull T[] arr) {
+        return new ArraySortedSet<T>(comparator, arr);
+    }
+
+    @Override
+    public int size() {
+        return arr.length;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return arr.length > 0;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public boolean contains(Object o) {
+        return Arrays.binarySearch((T[])arr, (T)o, comparator) >= 0;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public Iterator<T> iterator() {
+        return Iterators.forArray((T[])arr);
+    }
+
+    @Override
+    public Object[] toArray() {
+        return arr.clone();
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public <T> T[] toArray(T[] a) {
+        if (a.length <= arr.length) {
+            System.arraycopy(arr, 0, (Object[])a, 0, arr.length);
+            return a;
+        }
+        return Arrays.copyOf((T[])arr, arr.length);
+    }
+
+    @Override
+    public boolean add(T t) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean containsAll(Collection<?> c) {
+        for (Object o: c) {
+            if (!contains(o)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends T> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean retainAll(Collection<?> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void clear() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Comparator<? super T> comparator() {
+        return comparator;
+    }
+
+    @Override
+    public SortedSet<T> subSet(T fromElement, T toElement) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public SortedSet<T> headSet(T toElement) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public SortedSet<T> tailSet(T fromElement) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public T first() {
+        if (arr.length == 0) {
+            throw new NoSuchElementException();
+        }
+        return (T)arr[0];
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public T last() {
+        if (arr.length == 0) {
+            throw new NoSuchElementException();
+        }
+        return (T)arr[arr.length-1];
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 0;
+        for (Object o: arr) {
+            result += o.hashCode();
+        }
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null) {
+            return false;
+        }
+        if (o instanceof SortedSet) {
+            SortedSet other = (SortedSet)o;
+            if (arr.length != other.size()) {
+                return false;
+            }
+            return Iterators.elementsEqual(iterator(), other.iterator());
+        }
+        if (o instanceof Set) {
+            Set other = (Set)o;
+            if (arr.length != other.size()) {
+                return false;
+            }
+            return this.containsAll(other);
+        }
+        return false;
+    }
+}

util/src/main/java/org/jf/util/ImmutableSortedSetConverter.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2012, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.jf.util;
+
+import com.google.common.collect.ImmutableSortedSet;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.SortedSet;
+
+public abstract class ImmutableSortedSetConverter<ImmutableItem, Item> {
+
+    @Nonnull
+    public ImmutableSortedSet<ImmutableItem> convert(@Nonnull Comparator<? super ImmutableItem> comparator,
+                                                     @Nullable final Iterable<? extends Item> iterable) {
+        if (iterable == null) {
+            return ImmutableSortedSet.of();
+        }
+
+        boolean needsCopy = false;
+        if (iterable instanceof ImmutableSortedSet &&
+                ((ImmutableSortedSet)iterable).comparator().equals(comparator)) {
+            for (Item element: iterable) {
+                if (!isImmutable(element)) {
+                    needsCopy = true;
+                    break;
+                }
+            }
+        } else {
+            needsCopy = true;
+        }
+
+        if (!needsCopy) {
+            return (ImmutableSortedSet<ImmutableItem>)iterable;
+        }
+
+        final Iterator<? extends Item> iter = iterable.iterator();
+
+
+        return ImmutableSortedSet.copyOf(comparator, new Iterator<ImmutableItem>() {
+            @Override public boolean hasNext() { return iter.hasNext(); }
+            @Override public ImmutableItem next() { return makeImmutable(iter.next()); }
+            @Override public void remove() { iter.remove(); }
+        });
+    }
+
+    @Nonnull
+    public SortedSet<ImmutableItem> convert(@Nonnull Comparator<? super ImmutableItem> comparator,
+                                            @Nullable final SortedSet<? extends Item> sortedSet) {
+        if (sortedSet == null || sortedSet.size() == 0) {
+            return ImmutableSortedSet.of();
+        }
+
+        @SuppressWarnings("unchecked")
+        ImmutableItem[] newItems = (ImmutableItem[])new Object[sortedSet.size()];
+        int index = 0;
+        for (Item item: sortedSet) {
+            newItems[index++] = makeImmutable(item);
+        }
+
+        return ArraySortedSet.of(comparator, newItems);
+    }
+
+    protected abstract boolean isImmutable(@Nonnull Item item);
+    @Nonnull protected abstract ImmutableItem makeImmutable(@Nonnull Item item);
+}

util/src/main/java/org/jf/util/ImmutableUtils.java

@@ -32,15 +32,23 @@
 package org.jf.util;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSortedSet;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
-public class ImmutableListUtils {
+public class ImmutableUtils {
     @Nonnull public static <T> ImmutableList<T> nullToEmptyList(@Nullable ImmutableList<T> list) {
         if (list == null) {
             return ImmutableList.of();
         }
         return list;
     }
+
+    @Nonnull public static <T> ImmutableSortedSet<T> nullToEmptySortedSet(@Nullable ImmutableSortedSet<T> set) {
+        if (set == null) {
+            return ImmutableSortedSet.of();
+        }
+        return set;
+    }
 }