org.springframework.webflow.context.StringKeyedMapAdapter Maven / Gradle / Ivy
/*
* Copyright 2002-2006 the original author or authors.
*
* Licensed 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.springframework.webflow.context;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* Base class for attribute map adapters whose keys are String values. Concrete`
* classes need only implement the abstract hook method defined by this class.
*
* @author Keith Donald
*/
public abstract class StringKeyedMapAdapter implements Map {
private Set keySet;
private Collection values;
private Set entrySet;
public void clear() {
for (Iterator it = getAttributeNames(); it.hasNext();) {
removeAttribute((String)it.next());
}
}
public boolean containsKey(Object key) {
return getAttribute(key.toString()) != null;
}
public boolean containsValue(Object value) {
if (value == null) {
return false;
}
for (Iterator it = getAttributeNames(); it.hasNext();) {
Object aValue = getAttribute((String)it.next());
if (value.equals(aValue)) {
return true;
}
}
return false;
}
public Set entrySet() {
return (entrySet != null) ? entrySet : (entrySet = new EntrySet());
}
public Object get(Object key) {
return getAttribute(key.toString());
}
public boolean isEmpty() {
return !getAttributeNames().hasNext();
}
public Set keySet() {
return (keySet != null) ? keySet : (keySet = new KeySet());
}
public Object put(Object key, Object value) {
String stringKey = String.valueOf(key);
Object previousValue = getAttribute(stringKey);
setAttribute(stringKey, value);
return previousValue;
}
public void putAll(Map map) {
for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
Entry entry = (Entry)it.next();
setAttribute(entry.getKey().toString(), entry.getValue());
}
}
public Object remove(Object key) {
String stringKey = key.toString();
Object retval = getAttribute(stringKey);
removeAttribute(stringKey);
return retval;
}
public int size() {
int size = 0;
for (Iterator it = getAttributeNames(); it.hasNext();) {
size++;
it.next();
}
return size;
}
public Collection values() {
return (values != null) ? values : (values = new Values());
}
/**
* Hook method that needs to be implemented by concrete subclasses.
* Gets a value associated with a key.
* @param key the key to lookup
* @return the associated value, or null if none
*/
protected abstract Object getAttribute(String key);
/**
* Hook method that needs to be implemented by concrete subclasses.
* Puts a key-value pair in the map, overwriting any possible earlier
* value associated with the same key.
* @param key the key to associate the value with
* @param value the value to associate with the key
*/
protected abstract void setAttribute(String key, Object value);
/**
* Hook method that needs to be implemented by concrete subclasses.
* Removes a key and its associated value from the map.
* @param key the key to remove
*/
protected abstract void removeAttribute(String key);
/**
* Hook method that needs to be implemented by concrete subclasses.
* Returns an enumeration listing all keys known to the map.
* @return the key enumeration
*/
protected abstract Iterator getAttributeNames();
// internal helper classes
private abstract class AbstractSet extends java.util.AbstractSet {
public boolean isEmpty() {
return StringKeyedMapAdapter.this.isEmpty();
}
public int size() {
return StringKeyedMapAdapter.this.size();
}
public void clear() {
StringKeyedMapAdapter.this.clear();
}
}
private class KeySet extends AbstractSet {
public Iterator iterator() {
return new KeyIterator();
}
public boolean contains(Object o) {
return StringKeyedMapAdapter.this.containsKey(o);
}
public boolean remove(Object o) {
return StringKeyedMapAdapter.this.remove(o) != null;
}
}
private class KeyIterator implements Iterator {
protected final Iterator it = getAttributeNames();
protected Object currentKey;
public void remove() {
if (currentKey == null) {
throw new NoSuchElementException("You must call next() at least once");
}
StringKeyedMapAdapter.this.remove(currentKey);
}
public boolean hasNext() {
return it.hasNext();
}
public Object next() {
return currentKey = it.next();
}
}
private class Values extends AbstractSet {
public Iterator iterator() {
return new ValuesIterator();
}
public boolean contains(Object o) {
return StringKeyedMapAdapter.this.containsValue(o);
}
public boolean remove(Object o) {
if (o == null) {
return false;
}
for (Iterator it = iterator(); it.hasNext();) {
if (o.equals(it.next())) {
it.remove();
return true;
}
}
return false;
}
}
private class ValuesIterator extends KeyIterator {
public Object next() {
super.next();
return StringKeyedMapAdapter.this.get(currentKey);
}
}
private class EntrySet extends AbstractSet {
public Iterator iterator() {
return new EntryIterator();
}
public boolean contains(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry entry = (Entry)o;
Object key = entry.getKey();
Object value = entry.getValue();
if (key == null || value == null) {
return false;
}
return value.equals(StringKeyedMapAdapter.this.get(key));
}
public boolean remove(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry entry = (Entry)o;
Object key = entry.getKey();
Object value = entry.getValue();
if (key == null || value == null || !value.equals(StringKeyedMapAdapter.this.get(key))) {
return false;
}
return StringKeyedMapAdapter.this.remove(((Entry)o).getKey()) != null;
}
}
private class EntryIterator extends KeyIterator {
public Object next() {
super.next();
return new EntrySetEntry(currentKey);
}
}
private class EntrySetEntry implements Entry {
private final Object currentKey;
public EntrySetEntry(Object currentKey) {
this.currentKey = currentKey;
}
public Object getKey() {
return currentKey;
}
public Object getValue() {
return StringKeyedMapAdapter.this.get(currentKey);
}
public Object setValue(Object value) {
return StringKeyedMapAdapter.this.put(currentKey, value);
}
}
}