/*
* @(#)SimpleBindings.java 1.4 05/11/17 14:24:14
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTAIL. Use is subject to license terms.
*/
package javax.script;
import java.util.Map;
import java.util.HashMap;
import java.util.Collection;
import java.util.Set;
/**
* A simple implementation of Bindings backed by
* a <code>HashMap</code> or some other specified <code>Map</code>.
*
* @author Mike Grogan
* @version 1.0
* @since 1.6
*/
public class SimpleBindings implements Bindings {
/**
* The <code>Map</code> field stores the attributes.
*/
private Map<String,Object> map;
/**
* Constructor uses an existing <code>Map</code> to store the values.
* @param m The <code>Map</code> backing this <code>SimpleBindings</code>.
* @throws NullPointerException if m is null
*/
public SimpleBindings(Map<String,Object> m) {
if (m == null) {
throw new NullPointerException();
}
this.map = m;
}
/**
* Default constructor uses a <code>HashMap</code>.
*/
public SimpleBindings() {
this(new HashMap<String,Object>());
}
/**
* Sets the specified key/value in the underlying <code>map</code> field.
*
* @param name Name of value
* @param value Value to set.
*
* @return Previous value for the specified key. Returns null if key was previously
* unset.
*
* @throws NullPointerException if the name is null.
* @throws IllegalArgumentException if the name is empty.
*/
public Object put(String name, Object value) {
checkKey(name);
return map.put(name,value);
}
/**
* <code>putAll</code> is implemented using <code>Map.putAll</code>.
*
* @param toMerge The <code>Map</code> of values to add.
*
* @throws NullPointerException
* if toMerge map is null or if some key in the map is null.
* @throws IllegalArgumentException
* if some key in the map is an empty String.
*/
public void putAll(Map<? extends String, ? extends Object> toMerge) {
if (toMerge == null) {
throw new NullPointerException("toMerge map is null");
}
for (Map.Entry<? extends String, ? extends Object> entry : toMerge.entrySet()) {
String key = entry.getKey();
checkKey(key);
put(key, entry.getValue());
}
}
/** {@inheritDoc} */
public void clear() {
map.clear();
}
/**
* Returns <tt>true</tt> if this map contains a mapping for the specified
* key. More formally, returns <tt>true</tt> if and only if
* this map contains a mapping for a key <tt>k</tt> such that
* <tt>(key==null ? k==null : key.equals(k))</tt>. (There can be
* at most one such mapping.)
*
* @param key key whose presence in this map is to be tested.
* @return <tt>true</tt> if this map contains a mapping for the specified
* key.
*
* @throws NullPointerException if key is null
* @throws ClassCastException if key is not String
* @throws IllegalArgumentException if key is empty String
*/
public boolean containsKey(Object key) {
checkKey(key);
return map.containsKey(key);
}
/** {@inheritDoc} */
public boolean containsValue(Object value) {
return map.containsValue(value);
}
/** {@inheritDoc} */
public Set<Map.Entry<String, Object>> entrySet() {
return map.entrySet();
}
/**
* Returns the value to which this map maps the specified key. Returns
* <tt>null</tt> if the map contains no mapping for this key. A return
* value of <tt>null</tt> does not <i>necessarily</i> indicate that the
* map contains no mapping for the key; it's also possible that the map
* explicitly maps the key to <tt>null</tt>. The <tt>containsKey</tt>
* operation may be used to distinguish these two cases.
*
* <p>More formally, if this map contains a mapping from a key
* <tt>k</tt> to a value <tt>v</tt> such that <tt>(key==null ? k==null :
* key.equals(k))</tt>, then this method returns <tt>v</tt>; otherwise
* it returns <tt>null</tt>. (There can be at most one such mapping.)
*
* @param key key whose associated value is to be returned.
* @return the value to which this map maps the specified key, or
* <tt>null</tt> if the map contains no mapping for this key.
*
* @throws NullPointerException if key is null
* @throws ClassCastException if key is not String
* @throws IllegalArgumentException if key is empty String
*/
public Object get(Object key) {
checkKey(key);
return map.get(key);
}
/** {@inheritDoc} */
public boolean isEmpty() {
return map.isEmpty();
}
/** {@inheritDoc} */
public Set<String> keySet() {
return map.keySet();
}
/**
* Removes the mapping for this key from this map if it is present
* (optional operation). More formally, if this map contains a mapping
* from key <tt>k</tt> to value <tt>v</tt> such that
* <code>(key==null ? k==null : key.equals(k))</code>, that mapping
* is removed. (The map can contain at most one such mapping.)
*
* <p>Returns the value to which the map previously associated the key, or
* <tt>null</tt> if the map contained no mapping for this key. (A
* <tt>null</tt> return can also indicate that the map previously
* associated <tt>null</tt> with the specified key if the implementation
* supports <tt>null</tt> values.) The map will not contain a mapping for
* the specified key once the call returns.
*
* @param key key whose mapping is to be removed from the map.
* @return previous value associated with specified key, or <tt>null</tt>
* if there was no mapping for key.
*
* @throws NullPointerException if key is null
* @throws ClassCastException if key is not String
* @throws IllegalArgumentException if key is empty String
*/
public Object remove(Object key) {
checkKey(key);
return map.remove(key);
}
/** {@inheritDoc} */
public int size() {
return map.size();
}
/** {@inheritDoc} */
public Collection<Object> values() {
return map.values();
}
private void checkKey(Object key) {
if (key == null) {
throw new NullPointerException("key can not be null");
}
if (!(key instanceof String)) {
throw new ClassCastException("key should be a String");
}
if (key.equals("")) {
throw new IllegalArgumentException("key can not be empty");
}
}
}
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