org.jruby.util.GenericMap Maven / Gradle / Ivy
/***** BEGIN LICENSE BLOCK *****
* Version: EPL 1.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* License Version 1.0 (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.eclipse.org/legal/epl-v10.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2006 Kresten Krab Thorup
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
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package org.jruby.util;
import java.util.AbstractCollection;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* A GenericMap is simply an abstract java.util.Map
* implementation for which subclasses really only need to implement
* the method entryIterator.
*
* @author Kresten Krab Thorup ([email protected])
*/
public abstract class GenericMap implements Map {
protected int size;
public int size() {
return size;
}
public boolean isEmpty() {
return size() == 0;
}
protected int keyHash(Object key) {
return key == null ? 0 : key.hashCode();
}
protected boolean keyEquals(Object containedKey, Object givenKey) {
return containedKey == null ? givenKey == null : containedKey.equals(givenKey);
}
protected int valueHash(Object value) {
return value == null ? 0 : value.hashCode();
}
protected boolean valueEquals(Object value1, Object value2) {
return value1 == null ? value2 == null : value1.equals(value2);
}
abstract class Entry implements Map.Entry {
@Override
public int hashCode() {
return keyHash(getKey()) ^ valueHash(getValue());
}
@Override
public boolean equals(Object other) {
if (other instanceof Map.Entry) {
Map.Entry ent = (Map.Entry) other;
return keyEquals(getKey(), ent.getKey()) && valueEquals(getValue(), ent.getValue());
}
return false;
}
}
public void putAll(Map other) {
if (other == this) return;
for (Iterator it = other.entrySet().iterator(); it.hasNext();) {
Map.Entry entry = (Map.Entry) it.next();
put(entry.getKey(), entry.getValue());
}
}
protected abstract Iterator entryIterator();
protected Iterator keyIterator() {
return new KeyIterator();
}
protected Iterator valueIterator() {
return new ValueIterator();
}
abstract class KeyOrValueIterator implements Iterator {
Iterator iter = entryIterator();
public boolean hasNext() {
return iter.hasNext();
}
protected Map.Entry nextEntry() {
return (Map.Entry) iter.next();
}
public void remove() {
throw new UnsupportedOperationException();
}
}
class KeyIterator extends KeyOrValueIterator {
public Object next() {
return nextEntry().getKey();
}
}
class ValueIterator extends KeyOrValueIterator {
public Object next() {
return nextEntry().getValue();
}
}
/**
* I don't quite understand why we need to replace this method from
* AbstractCollection, but it has been observed that toArray returns the
* *reverse* order of elements. --Kresten
*/
private static Object[] toArray(Object[] arr, int size, Iterator it) {
Object[] out;
if (arr != null && arr.length >= size) {
out = arr;
} else if (arr == null) {
out = new Object[size];
} else {
out = (Object[]) java.lang.reflect.Array.newInstance(arr.getClass().getComponentType(), size);
}
for (int i = 0; i < size; i++) {
out[i] = it.next();
}
if (out.length > size) out[size] = null;
return out;
}
public Collection values() {
return new AbstractCollection() {
public Iterator iterator() {
return valueIterator();
}
public int size() {
return GenericMap.this.size();
}
@Override
public Object[] toArray(Object[] arr) {
return GenericMap.toArray(arr, size(), iterator());
}
};
}
public Set keySet() {
return new AbstractSet() {
public Iterator iterator() {
return keyIterator();
}
public int size() {
return GenericMap.this.size();
}
@Override
public Object[] toArray(Object[] arr) {
return GenericMap.toArray(arr, size(), iterator());
}
};
}
@Override
public int hashCode() {
int code = 0;
for (Iterator it = entryIterator(); it.hasNext(); ) {
code += it.next().hashCode();
}
return code;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof Map)) return false;
Map map = (Map) other;
if (map.size() != size()) return false;
for (Iterator it = entryIterator(); it.hasNext();) {
Entry ent = (Entry) it.next();
Object key = ent.getKey();
Object val = ent.getValue();
if (map.containsKey(key)) {
Object otherVal = map.get(key);
if (!valueEquals(val, otherVal)) return false;
}
}
return true;
}
public Set entrySet() {
return new AbstractSet() {
public Iterator iterator() {
return entryIterator();
}
public int size() {
return size;
}
@Override
public Object[] toArray(Object[] arr) {
return GenericMap.toArray(arr, size(), iterator());
}
};
}
/** return the element with the given key */
public boolean containsValue(Object value) {
for (Iterator it = valueIterator(); it.hasNext(); ) {
if (valueEquals(value, it.next())) return true;
}
return false;
}
public boolean containsKey(Object key) {
return get(key) != null;
}
}
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