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/* * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ 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 * @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");        }    }}