TruffleLanguage.Env

java.lang.Object
- com.oracle.truffle.api.TruffleLanguage.Env

Enclosing class:

TruffleLanguage<C>
```
public static final class TruffleLanguage.Env
extends Object
```
Represents execution environment of the TruffleLanguage. Each active TruffleLanguage receives instance of the environment before any code is executed upon it. The environment has knowledge of all active languages and can exchange symbols between them.

Since:

0.8 or earlier

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`OutputStream`	`err()` Standard error writer for `PolyglotEngine` this language is being executed in.
`Map<String,Object>`	`getConfig()` Configuration arguments for this language.
`Map<String,InstrumentInfo>`	`getInstruments()` Returns a map instrument-id to instrument instance of all instruments that are installed in the environment.
`Map<String,LanguageInfo>`	`getLanguages()` Returns a map mime-type to language instance of all languages that are installed in the environment.
`Object`	`importSymbol(String globalName)` Asks the environment to go through other registered languages and find whether they export global symbol of specified name.
`Iterable<? extends Object>`	`importSymbols(String globalName)` Returns an iterable collection of global symbols that are exported for a given name.
`InputStream`	`in()` Input associated with `PolyglotEngine` this language is being executed in.
`boolean`	`isMimeTypeSupported(String mimeType)` Allows it to be determined if this `PolyglotEngine` can execute code written in a language with a given MIME type.
`<T> T`	`lookup(Class<T> type)` Looks additional service up.
`<S> S`	`lookup(InstrumentInfo instrument, Class<S> type)` Returns an additional service provided by this instrument, specified by type.
`<S> S`	`lookup(LanguageInfo language, Class<S> type)` Returns an additional service provided by the given language, specified by type.
`OutputStream`	`out()` Standard output writer for `PolyglotEngine` this language is being executed in.
`CallTarget`	`parse(Source source, String... argumentNames)` Evaluates source of (potentially different) language.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - importSymbol
```
public Object importSymbol(String globalName)
```
    Asks the environment to go through other registered languages and find whether they export global symbol of specified name. The expected return type is either TruffleObject, or one of the wrappers of Java primitive types ( Integer, Double).
    
    Parameters:
    
    globalName - the name of the symbol to search for
    
    Returns:
    
    object representing the symbol or null
    
    Since:
    
    0.8 or earlier
  - importSymbols
```
public Iterable<? extends Object> importSymbols(String globalName)
```
    Returns an iterable collection of global symbols that are exported for a given name. Multiple languages may export a symbol with a particular name. This method is intended to be used to disambiguate exported symbols. The objects returned from the iterable conform to interop semantics e.g. the expected returned type is either TruffleObject, or one of the wrappers of Java primitive types (like Integer, Double).
    
    Parameters:
    
    globalName - the name of the symbol to search for
    
    Returns:
    
    iterable returning objects representing the symbol
    
    Since:
    
    0.22
  - isMimeTypeSupported
```
public boolean isMimeTypeSupported(String mimeType)
```
    Allows it to be determined if this PolyglotEngine can execute code written in a language with a given MIME type.
    
    Returns:
    
    a boolean that indicates if the MIME type is supported
    
    Since:
    
    0.11
    
    See Also:
    
    Source.getMimeType(), TruffleLanguage.Env.parse(Source, String...)
  - parse
```
public CallTarget parse(Source source,
                        String... argumentNames)
```
    Evaluates source of (potentially different) language. The MIME type is used to identify the TruffleLanguage to use to perform the TruffleLanguage.parse(com.oracle.truffle.api.TruffleLanguage.ParsingRequest) . The names of arguments are parameters for the resulting {#link CallTarget} that allow the source to reference the actual parameters passed to CallTarget.call(java.lang.Object...).
    
    Parameters:
    
    source - the source to evaluate
    
    argumentNames - the names of CallTarget.call(java.lang.Object...) arguments that can be referenced from the source
    
    Returns:
    
    the call target representing the parsed result
    
    Since:
    
    0.8 or earlier
  - in
```
public InputStream in()
```
    Input associated with PolyglotEngine this language is being executed in.
    
    Returns:
    
    reader, never null
    
    Since:
    
    0.8 or earlier
  - out
```
public OutputStream out()
```
    Standard output writer for PolyglotEngine this language is being executed in.
    
    Returns:
    
    writer, never null
    
    Since:
    
    0.8 or earlier
  - err
```
public OutputStream err()
```
    Standard error writer for PolyglotEngine this language is being executed in.
    
    Returns:
    
    writer, never null
    
    Since:
    
    0.8 or earlier
  - lookup
```
public <T> T lookup(Class<T> type)
```
    Looks additional service up. An environment for a particular language and a PolyglotEngine may also be associated with additional services. One can request implementations of such services by calling this method with the type identifying the requested service and its API. Services that can be obtained via this method include Instrumenter and others.
    
    Type Parameters:
    
    T - type of requested service
    
    Parameters:
    
    type - class of requested service
    
    Returns:
    
    instance of T or null if there is no such service available
    
    Since:
    
    0.12
  - lookup
```
public <S> S lookup(InstrumentInfo instrument,
                    Class<S> type)
```
    Returns an additional service provided by this instrument, specified by type. If an instrument is not enabled, it will be enabled automatically by requesting a supported service. If the instrument does not provide a service for a given type it will not be enabled automatically.
    
    Type Parameters:
    
    S - the requested type
    
    Parameters:
    
    instrument - identification of the instrument to query
    
    type - the class of the requested type
    
    Returns:
    
    the registered service or null if none is found
    
    Since:
    
    0.26
  - lookup
```
public <S> S lookup(LanguageInfo language,
                    Class<S> type)
```
    Returns an additional service provided by the given language, specified by type. If an language is not loaded, it will not be automatically loaded by requesting a service. In order to ensure a language to be loaded at least one Source must be parsed first.
    
    Type Parameters:
    
    S - the requested type
    
    Parameters:
    
    language - the language to query
    
    type - the class of the requested type
    
    Returns:
    
    the registered service or null if none is found
    
    Since:
    
    0.26
  - getLanguages
```
public Map<String,LanguageInfo> getLanguages()
```
    Returns a map mime-type to language instance of all languages that are installed in the environment. Using the language instance additional services can be looked up .
    
    Since:
    
    0.26
  - getInstruments
```
public Map<String,InstrumentInfo> getInstruments()
```
    Returns a map instrument-id to instrument instance of all instruments that are installed in the environment. Using the instrument instance additional services can be looked up .
    
    Since:
    
    0.26
  - getConfig
```
public Map<String,Object> getConfig()
```
    Configuration arguments for this language. Arguments set when constructing the engine are accessible via this map. This method (in combination with PolyglotEngine.Builder.config(java.lang.String, java.lang.String, java.lang.Object)) provides a straight-forward way to pass implementation-level arguments, as typically specified on a command line, to the languages.
```
String[] args = {"--kernel", "Kernel.som", "--instrument", "dyn-metrics"};
PolyglotEngine.PolyglotEngine.Builder builder = PolyglotEngine.newBuilder();
builder.config(YourLang.MIME_TYPE, "CMD_ARGS", args);
PolyglotEngine engine = builder.build();
```
    In contrast to global symbols the provided values are passed in exactly as specified, because these configuration arguments are strictly at the implementation level and not language-level objects. These configuration arguments are available when creating the language context to make it possible to take them into account before the language gets ready for execution. This is the most common way to access them:
```
class MyLanguage extends TruffleLanguage<Context> {
    @Override
    protected Context createContext(TruffleLanguage.Env env) {
        String[] args = (String[]) env.getConfig().get("CMD_ARGS");
        return new Context(args);
    }
}
```
    Returns:
    
    read-only view of configuration options for this language
    
    Since:
    
    0.11

Class TruffleLanguage.Env

Method Summary

Methods inherited from class java.lang.Object

Method Detail

importSymbol

importSymbols

isMimeTypeSupported

parse

in

out

err

lookup

lookup

lookup

getLanguages

getInstruments

getConfig