1 /*

     2  * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package javax.script;

    27 

    28 import java.util.Map;

    29 import java.util.HashMap;

    30 import java.util.Collection;

    31 import java.util.Set;

    32 

    33 /**

    34  * A simple implementation of Bindings backed by

    35  * a <code>HashMap</code> or some other specified <code>Map</code>.

    36  *

    37  * @author Mike Grogan

    38  * @since 1.6

    39  */

    40 public class SimpleBindings implements Bindings {

    41 

    42     /**

    43      * The <code>Map</code> field stores the attributes.

    44      */

    45     private Map<String,Object> map;

    46 

    47     /**

    48      * Constructor uses an existing <code>Map</code> to store the values.

    49      * @param m The <code>Map</code> backing this <code>SimpleBindings</code>.

    50      * @throws NullPointerException if m is null

    51      */

    52     public SimpleBindings(Map<String,Object> m) {

    53         if (m == null) {

    54             throw new NullPointerException();

    55         }

    56         this.map = m;

    57     }

    58 

    59     /**

    60      * Default constructor uses a <code>HashMap</code>.

    61      */

    62     public SimpleBindings() {

    63         this(new HashMap<String,Object>());

    64     }

    65 

    66     /**

    67      * Sets the specified key/value in the underlying <code>map</code> field.

    68      *

    69      * @param name Name of value

    70      * @param value Value to set.

    71      *

    72      * @return Previous value for the specified key.  Returns null if key was previously

    73      * unset.

    74      *

    75      * @throws NullPointerException if the name is null.

    76      * @throws IllegalArgumentException if the name is empty.

    77      */

    78     public Object put(String name, Object value) {

    79         checkKey(name);

    80         return map.put(name,value);

    81     }

    82 

    83     /**

    84      * <code>putAll</code> is implemented using <code>Map.putAll</code>.

    85      *

    86      * @param toMerge The <code>Map</code> of values to add.

    87      *

    88      * @throws NullPointerException

    89      *         if toMerge map is null or if some key in the map is null.

    90      * @throws IllegalArgumentException

    91      *         if some key in the map is an empty String.

    92      */

    93     public void putAll(Map<? extends String, ? extends Object> toMerge) {

    94         if (toMerge == null) {

    95             throw new NullPointerException("toMerge map is null");

    96         }

    97         for (Map.Entry<? extends String, ? extends Object> entry : toMerge.entrySet()) {

    98             String key = entry.getKey();

    99             checkKey(key);

   100             put(key, entry.getValue());

   101         }

   102     }

   103 

   104     /** {@inheritDoc} */

   105     public void clear() {

   106         map.clear();

   107     }

   108 

   109     /**

   110      * Returns <tt>true</tt> if this map contains a mapping for the specified

   111      * key.  More formally, returns <tt>true</tt> if and only if

   112      * this map contains a mapping for a key <tt>k</tt> such that

   113      * <tt>(key==null ? k==null : key.equals(k))</tt>.  (There can be

   114      * at most one such mapping.)

   115      *

   116      * @param key key whose presence in this map is to be tested.

   117      * @return <tt>true</tt> if this map contains a mapping for the specified

   118      *         key.

   119      *

   120      * @throws NullPointerException if key is null

   121      * @throws ClassCastException if key is not String

   122      * @throws IllegalArgumentException if key is empty String

   123      */

   124     public boolean containsKey(Object key) {

   125         checkKey(key);

   126         return map.containsKey(key);

   127     }

   128 

   129     /** {@inheritDoc} */

   130     public boolean containsValue(Object value) {

   131         return map.containsValue(value);

   132     }

   133 

   134     /** {@inheritDoc} */

   135     public Set<Map.Entry<String, Object>> entrySet() {

   136         return map.entrySet();

   137     }

   138 

   139     /**

   140      * Returns the value to which this map maps the specified key.  Returns

   141      * <tt>null</tt> if the map contains no mapping for this key.  A return

   142      * value of <tt>null</tt> does not <i>necessarily</i> indicate that the

   143      * map contains no mapping for the key; it's also possible that the map

   144      * explicitly maps the key to <tt>null</tt>.  The <tt>containsKey</tt>

   145      * operation may be used to distinguish these two cases.

   146      *

   147      * <p>More formally, if this map contains a mapping from a key

   148      * <tt>k</tt> to a value <tt>v</tt> such that <tt>(key==null ? k==null :

   149      * key.equals(k))</tt>, then this method returns <tt>v</tt>; otherwise

   150      * it returns <tt>null</tt>.  (There can be at most one such mapping.)

   151      *

   152      * @param key key whose associated value is to be returned.

   153      * @return the value to which this map maps the specified key, or

   154      *         <tt>null</tt> if the map contains no mapping for this key.

   155      *

   156      * @throws NullPointerException if key is null

   157      * @throws ClassCastException if key is not String

   158      * @throws IllegalArgumentException if key is empty String

   159      */

   160     public Object get(Object key) {

   161         checkKey(key);

   162         return map.get(key);

   163     }

   164 

   165     /** {@inheritDoc} */

   166     public boolean isEmpty() {

   167         return map.isEmpty();

   168     }

   169 

   170     /** {@inheritDoc} */

   171     public Set<String> keySet() {

   172         return map.keySet();

   173     }

   174 

   175     /**

   176      * Removes the mapping for this key from this map if it is present

   177      * (optional operation).   More formally, if this map contains a mapping

   178      * from key <tt>k</tt> to value <tt>v</tt> such that

   179      * <code>(key==null ?  k==null : key.equals(k))</code>, that mapping

   180      * is removed.  (The map can contain at most one such mapping.)

   181      *

   182      * <p>Returns the value to which the map previously associated the key, or

   183      * <tt>null</tt> if the map contained no mapping for this key.  (A

   184      * <tt>null</tt> return can also indicate that the map previously

   185      * associated <tt>null</tt> with the specified key if the implementation

   186      * supports <tt>null</tt> values.)  The map will not contain a mapping for

   187      * the specified  key once the call returns.

   188      *

   189      * @param key key whose mapping is to be removed from the map.

   190      * @return previous value associated with specified key, or <tt>null</tt>

   191      *         if there was no mapping for key.

   192      *

   193      * @throws NullPointerException if key is null

   194      * @throws ClassCastException if key is not String

   195      * @throws IllegalArgumentException if key is empty String

   196      */

   197     public Object remove(Object key) {

   198         checkKey(key);

   199         return map.remove(key);

   200     }

   201 

   202     /** {@inheritDoc} */

   203     public int size() {

   204         return map.size();

   205     }

   206 

   207     /** {@inheritDoc} */

   208     public Collection<Object> values() {

   209         return map.values();

   210     }

   211 

   212     private void checkKey(Object key) {

   213         if (key == null) {

   214             throw new NullPointerException("key can not be null");

   215         }

   216         if (!(key instanceof String)) {

   217             throw new ClassCastException("key should be a String");

   218         }

   219         if (key.equals("")) {

   220             throw new IllegalArgumentException("key can not be empty");

   221         }

   222     }

   223 }