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Added test cases + fixed some hard to find bugs.

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Harald Kuhr
2012-01-25 16:11:58 +01:00
parent d36d828110
commit b92caf121d
2 changed files with 564 additions and 90 deletions
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171
common/common-lang/src/main/java/com/twelvemonkeys/util/CollectionUtil.java
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@@ -28,17 +28,21 @@
package com.twelvemonkeys.util;
import com.twelvemonkeys.lang.Validate;
import java.lang.reflect.Array;
import java.util.*;
import static com.twelvemonkeys.lang.Validate.isTrue;
import static com.twelvemonkeys.lang.Validate.notNull;
/**
* A utility class with some useful collection-related functions.
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @author <A href="mailto:eirik.torske@twelvemonkeys.no">Eirik Torske</A>
* @author last modified by $Author: haku $
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/util/CollectionUtil.java#3 $
* @todo move makeList and makeSet to StringUtil?
* @version $Id: com/twelvemonkeys/util/CollectionUtil.java#3 $
* @see Collections
* @see Arrays
*/
@@ -51,8 +55,6 @@ public final class CollectionUtil {
*/
@SuppressWarnings({"UnusedDeclaration", "UnusedAssignment", "unchecked"})
public static void main(String[] pArgs) {
test();
int howMany = 1000;
if (pArgs.length > 0) {
@@ -257,7 +259,7 @@ public final class CollectionUtil {
* If the sub array is same length as the original
* ({@code pStart == 0}), the original array will be returned.
*
* @param pArray the origianl array
* @param pArray the original array
* @param pStart the start index of the original array
* @return a subset of the original array, or the original array itself,
* if {@code pStart} is 0.
@@ -270,16 +272,33 @@ public final class CollectionUtil {
return subArray(pArray, pStart, -1);
}
/**
* Creates an array containing a subset of the original array.
* If the sub array is same length as the original
* ({@code pStart == 0}), the original array will be returned.
*
* @param pArray the original array
* @param pStart the start index of the original array
* @return a subset of the original array, or the original array itself,
* if {@code pStart} is 0.
*
* @throws IllegalArgumentException if {@code pArray} is {@code null}
* @throws ArrayIndexOutOfBoundsException if {@code pStart} < 0
*/
public static <T> T[] subArray(T[] pArray, int pStart) {
return subArray(pArray, pStart, -1);
}
/**
* Creates an array containing a subset of the original array.
* If the {@code pLength} parameter is negative, it will be ignored.
* If there are not {@code pLength} elements in the original array
* after {@code pStart}, the {@code pLength} paramter will be
* after {@code pStart}, the {@code pLength} parameter will be
* ignored.
* If the sub array is same length as the original, the original array will
* be returned.
*
* @param pArray the origianl array
* @param pArray the original array
* @param pStart the start index of the original array
* @param pLength the length of the new array
* @return a subset of the original array, or the original array itself,
@@ -292,9 +311,7 @@ public final class CollectionUtil {
*/
@SuppressWarnings({"SuspiciousSystemArraycopy"})
public static Object subArray(Object pArray, int pStart, int pLength) {
if (pArray == null) {
throw new IllegalArgumentException("array == null");
}
Validate.notNull(pArray, "array");
// Get component type
Class type;
@@ -321,7 +338,7 @@ public final class CollectionUtil {
Object result;
if (newLength < originalLength) {
// Create subarray & copy into
// Create sub array & copy into
result = Array.newInstance(type, newLength);
System.arraycopy(pArray, pStart, result, 0, newLength);
}
@@ -335,7 +352,33 @@ public final class CollectionUtil {
return result;
}
/**
* Creates an array containing a subset of the original array.
* If the {@code pLength} parameter is negative, it will be ignored.
* If there are not {@code pLength} elements in the original array
* after {@code pStart}, the {@code pLength} parameter will be
* ignored.
* If the sub array is same length as the original, the original array will
* be returned.
*
* @param pArray the original array
* @param pStart the start index of the original array
* @param pLength the length of the new array
* @return a subset of the original array, or the original array itself,
* if {@code pStart} is 0 and {@code pLength} is either
* negative, or greater or equal to {@code pArray.length}.
*
* @throws IllegalArgumentException if {@code pArray} is {@code null}
* @throws ArrayIndexOutOfBoundsException if {@code pStart} < 0
*/
@SuppressWarnings("unchecked")
public static <T> T[] subArray(T[] pArray, int pStart, int pLength) {
return (T[]) subArray((Object) pArray, pStart, pLength);
}
public static <T> Iterator<T> iterator(final Enumeration<T> pEnum) {
notNull(pEnum, "enumeration");
return new Iterator<T>() {
public boolean hasNext() {
return pEnum.hasMoreElements();
@@ -361,8 +404,8 @@ public final class CollectionUtil {
* the given collection.
* @throws ClassCastException class of the specified element prevents it
* from being added to this collection.
* @throws NullPointerException if the specified element is null and this
* collection does not support null elements.
* @throws NullPointerException if the specified element is {@code null} and this
* collection does not support {@code null} elements.
* @throws IllegalArgumentException some aspect of this element prevents
* it from being added to this collection.
*/
@@ -372,7 +415,7 @@ public final class CollectionUtil {
}
}
// Is there a usecase where Arrays.asList(pArray).iterator() can't ne used?
// Is there a use case where Arrays.asList(pArray).iterator() can't ne used?
/**
* Creates a thin {@link Iterator} wrapper around an array.
*
@@ -383,7 +426,7 @@ public final class CollectionUtil {
* {@code pLength > pArray.length - pStart}
*/
public static <E> ListIterator<E> iterator(final E[] pArray) {
return iterator(pArray, 0, pArray.length);
return iterator(pArray, 0, notNull(pArray).length);
}
/**
@@ -408,7 +451,7 @@ public final class CollectionUtil {
* @return a new {@code Map} of same type as {@code pSource}
* @throws IllegalArgumentException if {@code pSource == null},
* or if a new map can't be instantiated,
* or if source map contains duplaicates.
* or if source map contains duplicates.
*
* @see #invert(java.util.Map, java.util.Map, DuplicateHandler)
*/
@@ -424,7 +467,7 @@ public final class CollectionUtil {
* @param pResult the map used to contain the result, may be {@code null},
* in that case a new {@code Map} of same type as {@code pSource} is created.
* The result map <em>should</em> be empty, otherwise duplicate values will need to be resolved.
* @param pHandler duplicate handler, may be {@code null} if source map don't contain dupliate values
* @param pHandler duplicate handler, may be {@code null} if source map don't contain duplicate values
* @return {@code pResult}, or a new {@code Map} if {@code pResult == null}
* @throws IllegalArgumentException if {@code pSource == null},
* or if result map is {@code null} and a new map can't be instantiated,
@@ -476,20 +519,20 @@ public final class CollectionUtil {
return result;
}
public static <T> Comparator<T> reverseOrder(Comparator<T> pOriginal) {
public static <T> Comparator<T> reverseOrder(final Comparator<T> pOriginal) {
return new ReverseComparator<T>(pOriginal);
}
private static class ReverseComparator<T> implements Comparator<T> {
private Comparator<T> mComparator;
private final Comparator<T> comparator;
public ReverseComparator(Comparator<T> pComparator) {
mComparator = pComparator;
public ReverseComparator(final Comparator<T> pComparator) {
comparator = notNull(pComparator);
}
public int compare(T pLeft, T pRight) {
int result = mComparator.compare(pLeft, pRight);
int result = comparator.compare(pLeft, pRight);
// We can't simply return -result, as -Integer.MIN_VALUE == Integer.MIN_VALUE.
return -(result | (result >>> 1));
@@ -516,73 +559,21 @@ public final class CollectionUtil {
return (T) pCollection;
}
@SuppressWarnings({"UnusedDeclaration"})
static void test() {
List list = Collections.singletonList("foo");
@SuppressWarnings({"unchecked"})
Set set = new HashSet(list);
List<String> strs0 = CollectionUtil.generify(list, String.class);
List<Object> objs0 = CollectionUtil.generify(list, String.class);
// List<String> strs01 = CollectionUtil.generify(list, Object.class); // Not okay
try {
List<String> strs1 = CollectionUtil.generify(set, String.class); // Not ok, runtime CCE unless set is null
}
catch (RuntimeException e) {
e.printStackTrace();
}
try {
ArrayList<String> strs01 = CollectionUtil.generify(list, String.class); // Not ok, runtime CCE unless list is null
}
catch (RuntimeException e) {
e.printStackTrace();
}
Set<String> setstr1 = CollectionUtil.generify(set, String.class);
Set<Object> setobj1 = CollectionUtil.generify(set, String.class);
try {
Set<Object> setobj44 = CollectionUtil.generify(list, String.class); // Not ok, runtime CCE unless list is null
}
catch (RuntimeException e) {
e.printStackTrace();
}
List<String> strs2 = CollectionUtil.<List<String>, String>generify2(list);
List<Object> objs2 = CollectionUtil.<List<Object>, String>generify2(list);
// List<String> morestrs = CollectionUtil.<List<Object>, String>generify2(list); // Not ok
try {
List<String> strs3 = CollectionUtil.<List<String>, String>generify2(set); // Not ok, runtime CCE unless set is null
}
catch (RuntimeException e) {
e.printStackTrace();
}
}
private static class ArrayIterator<E> implements ListIterator<E> {
private int mIndex;
private final int mStart;
private final int mLength;
private final E[] mArray;
private int next;
private final int start;
private final int length;
private final E[] array;
public ArrayIterator(E[] pArray, int pStart, int pLength) {
if (pArray == null) {
throw new IllegalArgumentException("array == null");
}
if (pStart < 0) {
throw new IllegalArgumentException("start < 0");
}
if (pLength > pArray.length - pStart) {
throw new IllegalArgumentException("length > array.length - start");
}
mArray = pArray;
mStart = pStart;
mLength = pLength;
mIndex = mStart;
public ArrayIterator(final E[] pArray, final int pStart, final int pLength) {
array = notNull(pArray, "array");
start = isTrue(pStart >= 0, pStart, "start < 0: %d");
length = isTrue(pLength <= pArray.length - pStart, pLength, "length > array.length - start: %d");
next = start;
}
public boolean hasNext() {
return mIndex < mLength + mStart;
return next < length + start;
}
public E next() {
@@ -591,7 +582,7 @@ public final class CollectionUtil {
}
try {
return mArray[mIndex++];
return array[next++];
}
catch (ArrayIndexOutOfBoundsException e) {
NoSuchElementException nse = new NoSuchElementException(e.getMessage());
@@ -609,11 +600,11 @@ public final class CollectionUtil {
}
public boolean hasPrevious() {
return mIndex > mStart;
return next > start;
}
public int nextIndex() {
return mIndex + 1;
return next - start;
}
public E previous() {
@@ -622,7 +613,7 @@ public final class CollectionUtil {
}
try {
return mArray[mIndex--];
return array[--next];
}
catch (ArrayIndexOutOfBoundsException e) {
NoSuchElementException nse = new NoSuchElementException(e.getMessage());
@@ -632,11 +623,11 @@ public final class CollectionUtil {
}
public int previousIndex() {
return mIndex - 1;
return nextIndex() - 1;
}
public void set(E pElement) {
mArray[mIndex] = pElement;
array[next - 1] = pElement;
}
}
}