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25 
26 /**
27   * Given an enumeration of candidates, check whether each
28   * item in enumeration satifies the given filter.
29   * Each item is a Binding and the following is used to get its
30   * attributes for used by the filter:
31   *
32   *   ((DirContext)item.getObject()).getAttributes("").
33   * If item.getObject() is not an DirContext, the item is skipped
34   *
35   * The items in the enumeration are obtained one at a time as
36   * items from the search enumeration are requested.
37   *
38   * @author Rosanna Lee
39   */
40 
41 package com.sun.jndi.toolkit.dir;
42 
43 import javax.naming.*;
44 import javax.naming.directory.*;
45 import javax.naming.spi.DirectoryManager;
46 
47 import java.util.NoSuchElementException;
48 import java.util.Hashtable;
49 
50 final public class LazySearchEnumerationImpl
51         implements NamingEnumeration<SearchResult> {
52     private NamingEnumeration<Binding> candidates;
53     private SearchResult nextMatch = null;
54     private SearchControls cons;
55     private AttrFilter filter;
56     private Context context;
57     private Hashtable<String, Object> env;
58     private boolean useFactory = true;
59 
LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates, AttrFilter filter, SearchControls cons)60     public LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates,
61         AttrFilter filter, SearchControls cons) throws NamingException {
62             this.candidates = candidates;
63             this.filter = filter;
64 
65             if(cons == null) {
66                 this.cons = new SearchControls();
67             } else {
68                 this.cons = cons;
69             }
70     }
71 
72     @SuppressWarnings("unchecked")      // For Hashtable clone: env.clone()
LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates, AttrFilter filter, SearchControls cons, Context ctx, Hashtable<String, Object> env, boolean useFactory)73     public LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates,
74         AttrFilter filter, SearchControls cons,
75         Context ctx, Hashtable<String, Object> env, boolean useFactory)
76         throws NamingException {
77 
78             this.candidates = candidates;
79             this.filter = filter;
80             this.env = (Hashtable<String, Object>)
81                     ((env == null) ? null : env.clone());
82             this.context = ctx;
83             this.useFactory = useFactory;
84 
85             if(cons == null) {
86                 this.cons = new SearchControls();
87             } else {
88                 this.cons = cons;
89             }
90     }
91 
92 
LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates, AttrFilter filter, SearchControls cons, Context ctx, Hashtable<String, Object> env)93     public LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates,
94         AttrFilter filter, SearchControls cons,
95         Context ctx, Hashtable<String, Object> env) throws NamingException {
96             this(candidates, filter, cons, ctx, env, true);
97     }
98 
hasMore()99     public boolean hasMore() throws NamingException {
100         // find and do not remove from list
101         return findNextMatch(false) != null;
102     }
103 
hasMoreElements()104     public boolean hasMoreElements() {
105         try {
106             return hasMore();
107         } catch (NamingException e) {
108             return false;
109         }
110     }
111 
nextElement()112     public SearchResult nextElement() {
113         try {
114             return findNextMatch(true);
115         } catch (NamingException e) {
116             throw new NoSuchElementException(e.toString());
117         }
118     }
119 
next()120     public SearchResult next() throws NamingException {
121         // find and remove from list
122         return (findNextMatch(true));
123     }
124 
close()125     public void close() throws NamingException {
126         if (candidates != null) {
127             candidates.close();
128         }
129     }
130 
findNextMatch(boolean remove)131     private SearchResult findNextMatch(boolean remove) throws NamingException {
132         SearchResult answer;
133         if (nextMatch != null) {
134             answer = nextMatch;
135             if (remove) {
136                 nextMatch = null;
137             }
138             return answer;
139         } else {
140             // need to find next match
141             Binding next;
142             Object obj;
143             Attributes targetAttrs;
144             while (candidates.hasMore()) {
145                 next = candidates.next();
146                 obj = next.getObject();
147                 if (obj instanceof DirContext) {
148                     targetAttrs = ((DirContext)(obj)).getAttributes("");
149                     if (filter.check(targetAttrs)) {
150                         if (!cons.getReturningObjFlag()) {
151                             obj = null;
152                         } else if (useFactory) {
153                             try {
154                                 // Give name only if context non-null,
155                                 // otherwise, name will be interpreted relative
156                                 // to initial context (not what we want)
157                                 Name nm = (context != null ?
158                                     new CompositeName(next.getName()) : null);
159                                 obj = DirectoryManager.getObjectInstance(obj,
160                                     nm, context, env, targetAttrs);
161                             } catch (NamingException e) {
162                                 throw e;
163                             } catch (Exception e) {
164                                 NamingException e2 = new NamingException(
165                                     "problem generating object using object factory");
166                                 e2.setRootCause(e);
167                                 throw e2;
168                             }
169                         }
170                         answer = new SearchResult(next.getName(),
171                             next.getClassName(), obj,
172                             SearchFilter.selectAttributes(targetAttrs,
173                                 cons.getReturningAttributes()),
174                             true);
175                         if (!remove)
176                             nextMatch = answer;
177                         return answer;
178                     }
179                 }
180             }
181             return null;
182         }
183     }
184 }
185