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25 
26 package javax.annotation.processing;
27 
28 import java.util.Map;
29 import java.util.Locale;
30 import javax.lang.model.SourceVersion;
31 import javax.lang.model.util.Elements;
32 import javax.lang.model.util.Types;
33 
34 /**
35  * An annotation processing tool framework will {@linkplain
36  * Processor#init provide an annotation processor with an object
37  * implementing this interface} so the processor can use facilities
38  * provided by the framework to write new files, report error
39  * messages, and find other utilities.
40  *
41  * <p>Third parties may wish to provide value-add wrappers around the
42  * facility objects from this interface, for example a {@code Filer}
43  * extension that allows multiple processors to coordinate writing out
44  * a single source file.  To enable this, for processors running in a
45  * context where their side effects via the API could be visible to
46  * each other, the tool infrastructure must provide corresponding
47  * facility objects that are {@code .equals}, {@code Filer}s that are
48  * {@code .equals}, and so on.  In addition, the tool invocation must
49  * be able to be configured such that from the perspective of the
50  * running annotation processors, at least the chosen subset of helper
51  * classes are viewed as being loaded by the same class loader.
52  * (Since the facility objects manage shared state, the implementation
53  * of a wrapper class must know whether or not the same base facility
54  * object has been wrapped before.)
55  *
56  * @author Joseph D. Darcy
57  * @author Scott Seligman
58  * @author Peter von der Ah&eacute;
59  * @since 1.6
60  */
61 public interface ProcessingEnvironment {
62     /**
63      * Returns the processor-specific options passed to the annotation
64      * processing tool.  Options are returned in the form of a map from
65      * option name to option value.  For an option with no value, the
66      * corresponding value in the map is {@code null}.
67      *
68      * <p>See documentation of the particular tool infrastructure
69      * being used for details on how to pass in processor-specific
70      * options.  For example, a command-line implementation may
71      * distinguish processor-specific options by prefixing them with a
72      * known string like {@code "-A"}; other tool implementations may
73      * follow different conventions or provide alternative mechanisms.
74      * A given implementation may also provide implementation-specific
75      * ways of finding options passed to the tool in addition to the
76      * processor-specific options.
77      *
78      * @return the processor-specific options passed to the tool
79      */
getOptions()80     Map<String,String> getOptions();
81 
82     /**
83      * Returns the messager used to report errors, warnings, and other
84      * notices.
85      *
86      * @return the messager
87      */
getMessager()88     Messager getMessager();
89 
90     /**
91      * Returns the filer used to create new source, class, or auxiliary
92      * files.
93      *
94      * @return the filer
95      */
getFiler()96     Filer getFiler();
97 
98     /**
99      * Returns an implementation of some utility methods for
100      * operating on elements
101      *
102      * @return element utilities
103      */
getElementUtils()104     Elements getElementUtils();
105 
106     /**
107      * Returns an implementation of some utility methods for
108      * operating on types.
109      *
110      * @return type utilities
111      */
getTypeUtils()112     Types getTypeUtils();
113 
114     /**
115      * Returns the source version that any generated {@linkplain
116      * Filer#createSourceFile source} and {@linkplain
117      * Filer#createClassFile class} files should conform to.
118      *
119      * @return the source version to which generated source and class
120      *         files should conform to
121      * @see Processor#getSupportedSourceVersion
122      */
getSourceVersion()123     SourceVersion getSourceVersion();
124 
125     /**
126      * Returns the current locale or {@code null} if no locale is in
127      * effect.  The locale can be be used to provide localized
128      * {@linkplain Messager messages}.
129      *
130      * @return the current locale or {@code null} if no locale is in
131      * effect
132      */
getLocale()133     Locale getLocale();
134 
135     /**
136      * Returns {@code true} if <em>preview features</em> are enabled
137      * and {@code false} otherwise.
138      * @return whether or not preview features are enabled
139      *
140      * @implSpec The default implementation of this method returns
141      * {@code false}.
142      *
143      * @since 13
144      */
isPreviewEnabled()145     default boolean isPreviewEnabled() {
146         return false;
147     }
148 }
149