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/* * @(#)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"); } } }