org.apache.felix.resolver.util.CopyOnWriteSet Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.felix.resolver.util;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
public class CopyOnWriteSet implements Set, Cloneable {
Object[] data;
public CopyOnWriteSet() {
data = new Object[0];
}
public CopyOnWriteSet(CopyOnWriteSet col) {
data = col.data;
}
public CopyOnWriteSet(Collection col) {
data = col.toArray(new Object[col.size()]);
}
public Iterator iterator() {
return new Iterator() {
int idx = 0;
public boolean hasNext() {
return idx < data.length;
}
@SuppressWarnings("unchecked")
public E next() {
return (E) data[idx++];
}
public void remove() {
CopyOnWriteSet.this.remove(--idx);
}
};
}
public int size() {
return data.length;
}
public boolean add(E e) {
Object[] d = data;
if (d.length == 0) {
data = new Object[] {e};
} else {
for (Object o : d) {
if (o == null ? e == null : o.equals(e)) {
return false;
}
}
Object[] a = new Object[d.length + 1];
System.arraycopy(d, 0, a, 0, d.length);
a[d.length] = e;
data = a;
}
return true;
}
private void remove(int index) {
Object[] d = data;
int len = d.length;
Object[] a = new Object[len - 1];
int numMoved = len - index - 1;
if (index > 0) {
System.arraycopy(d, 0, a, 0, index);
}
if (numMoved > 0) {
System.arraycopy(d, index + 1, a, index, numMoved);
}
data = a;
}
public Object[] toArray() {
return data.clone();
}
@SuppressWarnings("unchecked")
public T[] toArray(T[] a) {
int size = data.length;
if (a.length < size)
// Make a new array of a's runtime type, but my contents:
return (T[]) copyOf(data, size, a.getClass());
System.arraycopy(data, 0, a, 0, size);
if (a.length > size)
a[size] = null;
return a;
}
@Override
public boolean equals(Object o) {
if (!(o instanceof CopyOnWriteSet)) {
return false;
}
Object[] o1 = data;
@SuppressWarnings("rawtypes")
Object[] o2 = ((CopyOnWriteSet) o).data;
if (o1 == o2) {
return true;
}
int l = o1.length;
if (l != o2.length) {
return false;
}
loop:
for (int i = l; i-- > 0;) {
Object v1 = o1[i];
for (int j = l; j-- > 0;) {
Object v2 = o2[j];
if (v1 == v2)
continue loop;
if (v1 != null && v1.equals(v2))
continue loop;
}
return false;
}
return true;
}
@Override
public int hashCode() {
return Arrays.hashCode(data);
}
/**
* Clone this object
*
* @return a cloned object.
*/
@Override
@SuppressWarnings("unchecked")
public CopyOnWriteSet clone() {
try {
return (CopyOnWriteSet) super.clone();
} catch (CloneNotSupportedException exc) {
InternalError e = new InternalError();
e.initCause(exc);
throw e; //should never happen since we are cloneable
}
}
public boolean isEmpty() {
return size() == 0;
}
public boolean contains(Object o) {
throw new UnsupportedOperationException();
}
public boolean remove(Object o) {
int index;
if ((index = indexOf(o, data, data.length)) >= 0) {
remove(index);
return true;
}
return false;
}
private static int indexOf(Object o, Object[] d, int len) {
if (o == null) {
for (int i = len; i-- > 0;) {
if (d[i] == null)
return i;
}
} else {
for (int i = len; i-- > 0;) {
if (o.equals(d[i]))
return i;
}
}
return -1;
}
public boolean containsAll(Collection c) {
throw new UnsupportedOperationException();
}
public boolean addAll(Collection c) {
Object[] cs = c.toArray();
if (cs.length == 0)
return false;
Object[] elements = data;
int len = elements.length;
int added = 0;
// uniquify and compact elements in cs
for (int i = 0; i < cs.length; ++i) {
Object e = cs[i];
if (indexOf(e, elements, len) < 0 &&
indexOf(e, cs, added) < 0)
cs[added++] = e;
}
if (added > 0) {
Object[] newElements = copyOf(elements, len + added);
System.arraycopy(cs, 0, newElements, len, added);
data = newElements;
return true;
}
return false;
}
public boolean retainAll(Collection c) {
throw new UnsupportedOperationException();
}
public boolean removeAll(Collection c) {
throw new UnsupportedOperationException();
}
public void clear() {
throw new UnsupportedOperationException();
}
@SuppressWarnings("unchecked")
public static T[] copyOf(T[] original, int newLength) {
return (T[]) copyOf(original, newLength, original.getClass());
}
@SuppressWarnings("unchecked")
public static T[] copyOf(U[] original, int newLength, Class newType) {
T[] copy;
if ((Object) newType == Object[].class) {
copy = (T[]) new Object[newLength];
} else {
copy = (T[]) Array.newInstance(newType.getComponentType(), newLength);
}
System.arraycopy(original, 0, copy, 0, Math.min(original.length, newLength));
return copy;
}
}
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