Context (GWT 2.7.0)

java.lang.Object
- com.google.gwt.dev.js.rhino.Context

```
public class Context
extends Object
```
This class represents the runtime context of an executing script. Before executing a script, an instance of Context must be created and associated with the thread that will be executing the script. The Context will be used to store information about the executing of the script such as the call stack. Contexts are associated with the current thread using the enter() method.
The behavior of the execution engine may be altered through methods such as setErrorReporter.
Different forms of script execution are supported. Scripts may be evaluated from the source directly, or first compiled and then later executed. Interactive execution is also supported.
Some aspects of script execution, such as type conversions and object creation, may be accessed directly through methods of Context.

Author:

Norris Boyd, Brendan Eich

See Also:

Scriptable

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`errorReporterProperty`
`static int`	`FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME` if hasFeature(FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME) returns true, allow 'function (...) { ...
`static int`	`FEATURE_NON_ECMA_GET_YEAR` if hasFeature(FEATURE_NON_ECMA_GET_YEAR) returns true, Date.prototype.getYear subtructs 1900 only if 1900 <= date < 2000 in deviation with Ecma B.2.4
`static int`	`FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER` if hasFeature(RESERVED_KEYWORD_AS_IDENTIFIER) returns true, treat future reserved keyword (see Ecma-262, section 7.5.3) as ordinary identifiers but warn about this usage
`static int`	`FEATURE_TO_STRING_AS_SOURCE` if hasFeature(FEATURE_TO_STRING_AS_SOURCE) returns true, calling toString on JS objects gives JS source with code to create an object with all enumeratable fields of the original object instead of printing "[object ]".
`static String`	`languageVersionProperty`
`static int`	`VERSION_1_0` JavaScript 1.0
`static int`	`VERSION_1_1` JavaScript 1.1
`static int`	`VERSION_1_2` JavaScript 1.2
`static int`	`VERSION_1_3` JavaScript 1.3
`static int`	`VERSION_1_4` JavaScript 1.4
`static int`	`VERSION_1_5` JavaScript 1.5
`static int`	`VERSION_DEFAULT` The default version.
`static int`	`VERSION_UNKNOWN` The unknown version.

Constructor Summary

Constructors
Constructor and Description

Context()
Create a new Context.

Constructors
Constructor and Description
`Context()` Create a new Context.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static Context`	`enter()` Get a context associated with the current thread, creating one if need be.
`static Context`	`enter(Context cx)` Get a Context associated with the current thread, using the given Context if need be.
`static void`	`exit()` Exit a block of code requiring a Context.
`static Context`	`getCurrentContext()` Get the current Context.
`ErrorReporter`	`getErrorReporter()` Get the current error reporter.
`String`	`getImplementationVersion()` Get the implementation version.
`int`	`getLanguageVersion()` Get the current language version.
`Locale`	`getLocale()` Get the current locale.
`Object`	`getThreadLocal(Object key)` Get a value corresponding to a key.
`boolean`	`hasCompileFunctionsWithDynamicScope()` Return whether functions are compiled by this context using dynamic scope.
`boolean`	`hasFeature(int featureIndex)` Controls certain aspects of script semantics.
`void`	`putThreadLocal(Object key, Object value)` Put a value that can later be retrieved using a given key.
`void`	`removeThreadLocal(Object key)` Remove values from thread-local storage.
`static void`	`reportError(String message, String sourceName, int lineno, String lineSource, int lineOffset)` Report an error using the error reporter for the current thread.
`static void`	`reportWarning(String message, String sourceName, int lineno, String lineSource, int lineOffset)` Report a warning using the error reporter for the current thread.
`void`	`setCompileFunctionsWithDynamicScope(boolean flag)` Set whether functions compiled by this context should use dynamic scope.
`ErrorReporter`	`setErrorReporter(ErrorReporter reporter)` Change the current error reporter.
`void`	`setLanguageVersion(int version)` Set the language version.
`Locale`	`setLocale(Locale loc)` Set the current locale.

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, toString

- Field Detail
  - languageVersionProperty
```
public static final String languageVersionProperty
```
    See Also:
    
    Constant Field Values
  - errorReporterProperty
```
public static final String errorReporterProperty
```
    See Also:
    
    Constant Field Values
  - VERSION_UNKNOWN
```
public static final int VERSION_UNKNOWN
```
    The unknown version.
    
    See Also:
    
    Constant Field Values
  - VERSION_DEFAULT
```
public static final int VERSION_DEFAULT
```
    The default version.
    
    See Also:
    
    Constant Field Values
  - VERSION_1_0
```
public static final int VERSION_1_0
```
    JavaScript 1.0
    
    See Also:
    
    Constant Field Values
  - VERSION_1_1
```
public static final int VERSION_1_1
```
    JavaScript 1.1
    
    See Also:
    
    Constant Field Values
  - VERSION_1_2
```
public static final int VERSION_1_2
```
    JavaScript 1.2
    
    See Also:
    
    Constant Field Values
  - VERSION_1_3
```
public static final int VERSION_1_3
```
    JavaScript 1.3
    
    See Also:
    
    Constant Field Values
  - VERSION_1_4
```
public static final int VERSION_1_4
```
    JavaScript 1.4
    
    See Also:
    
    Constant Field Values
  - VERSION_1_5
```
public static final int VERSION_1_5
```
    JavaScript 1.5
    
    See Also:
    
    Constant Field Values
  - FEATURE_NON_ECMA_GET_YEAR
```
public static final int FEATURE_NON_ECMA_GET_YEAR
```
    if hasFeature(FEATURE_NON_ECMA_GET_YEAR) returns true, Date.prototype.getYear subtructs 1900 only if 1900 <= date < 2000 in deviation with Ecma B.2.4
    
    See Also:
    
    Constant Field Values
  - FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME
```
public static final int FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME
```
    if hasFeature(FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME) returns true, allow 'function (...) { ... }' to be syntax sugar for ' = function(...) { ... }', when is not simply identifier. See Ecma-262, section 11.2 for definition of
    
    See Also:
    
    Constant Field Values
  - FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER
```
public static final int FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER
```
    if hasFeature(RESERVED_KEYWORD_AS_IDENTIFIER) returns true, treat future reserved keyword (see Ecma-262, section 7.5.3) as ordinary identifiers but warn about this usage
    
    See Also:
    
    Constant Field Values
  - FEATURE_TO_STRING_AS_SOURCE
```
public static final int FEATURE_TO_STRING_AS_SOURCE
```
    if hasFeature(FEATURE_TO_STRING_AS_SOURCE) returns true, calling toString on JS objects gives JS source with code to create an object with all enumeratable fields of the original object instead of printing "[object ]". By default hasFeature(int) returns true only if the current JS version is set to VERSION_1_2.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Context
```
public Context()
```
    Create a new Context. Note that the Context must be associated with a thread before it can be used to execute a script.
    
    See Also:
    
    org.mozilla.javascript.Context#enter
- Method Detail
  - enter
```
public static Context enter()
```
    Get a context associated with the current thread, creating one if need be. The Context stores the execution state of the JavaScript engine, so it is required that the context be entered before execution may begin. Once a thread has entered a Context, then getCurrentContext() may be called to find the context that is associated with the current thread.
    Calling enter() will return either the Context currently associated with the thread, or will create a new context and associate it with the current thread. Each call to enter() must have a matching call to exit(). For example,
```
      Context cx = Context.enter();
      try {
          ...
          cx.evaluateString(...);
      }
      finally { Context.exit(); }
 
```
    Returns:
    
    a Context associated with the current thread
    
    See Also:
    
    org.mozilla.javascript.Context#getCurrentContext, org.mozilla.javascript.Context#exit
  - enter
```
public static Context enter(Context cx)
```
    Get a Context associated with the current thread, using the given Context if need be.
    The same as enter() except that cx is associated with the current thread and returned if the current thread has no associated context and cx is not associated with any other thread.
    
    Parameters:
    
    cx - a Context to associate with the thread if possible
    
    Returns:
    
    a Context associated with the current thread
  - exit
```
public static void exit()
```
    Exit a block of code requiring a Context. Calling exit() will remove the association between the current thread and a Context if the prior call to enter() on this thread newly associated a Context with this thread. Once the current thread no longer has an associated Context, it cannot be used to execute JavaScript until it is again associated with a Context.
    
    See Also:
    
    org.mozilla.javascript.Context#enter
  - getCurrentContext
```
public static Context getCurrentContext()
```
    Get the current Context. The current Context is per-thread; this method looks up the Context associated with the current thread.
    
    Returns:
    
    the Context associated with the current thread, or null if no context is associated with the current thread.
    
    See Also:
    
    org.mozilla.javascript.Context#enter, org.mozilla.javascript.Context#exit
  - getLanguageVersion
```
public int getLanguageVersion()
```
    Get the current language version.
    The language version number affects JavaScript semantics as detailed in the overview documentation.
    
    Returns:
    
    an integer that is one of VERSION_1_0, VERSION_1_1, etc.
  - setLanguageVersion
```
public void setLanguageVersion(int version)
```
    Set the language version.
    Setting the language version will affect functions and scripts compiled subsequently. See the overview documentation for version-specific behavior.
    
    Parameters:
    
    version - the version as specified by VERSION_1_0, VERSION_1_1, etc.
  - getImplementationVersion
```
public String getImplementationVersion()
```
    Get the implementation version.
    The implementation version is of the form
```
    "name langVer release relNum date"
 
```
    where name is the name of the product, langVer is the language version, relNum is the release number, and date is the release date for that specific release in the form "yyyy mm dd".
    Returns:
    
    a string that encodes the product, language version, release number, and date.
  - getErrorReporter
```
public ErrorReporter getErrorReporter()
```
    Get the current error reporter.
    
    See Also:
    
    org.mozilla.javascript.ErrorReporter
  - setErrorReporter
```
public ErrorReporter setErrorReporter(ErrorReporter reporter)
```
    Change the current error reporter.
    
    Returns:
    
    the previous error reporter
    
    See Also:
    
    org.mozilla.javascript.ErrorReporter
  - getLocale
```
public Locale getLocale()
```
    Get the current locale. Returns the default locale if none has been set.
    
    See Also:
    
    Locale
  - setLocale
```
public Locale setLocale(Locale loc)
```
    Set the current locale.
    
    See Also:
    
    Locale
  - reportWarning
```
public static void reportWarning(String message,
                                 String sourceName,
                                 int lineno,
                                 String lineSource,
                                 int lineOffset)
```
    Report a warning using the error reporter for the current thread.
    
    Parameters:
    
    message - the warning message to report
    
    sourceName - a string describing the source, such as a filename
    
    lineno - the starting line number
    
    lineSource - the text of the line (may be null)
    
    lineOffset - the offset into lineSource where problem was detected
    
    See Also:
    
    org.mozilla.javascript.ErrorReporter
  - reportError
```
public static void reportError(String message,
                               String sourceName,
                               int lineno,
                               String lineSource,
                               int lineOffset)
```
    Report an error using the error reporter for the current thread.
    
    Parameters:
    
    message - the error message to report
    
    sourceName - a string describing the source, such as a filename
    
    lineno - the starting line number
    
    lineSource - the text of the line (may be null)
    
    lineOffset - the offset into lineSource where problem was detected
    
    See Also:
    
    org.mozilla.javascript.ErrorReporter
  - getThreadLocal
```
public final Object getThreadLocal(Object key)
```
    Get a value corresponding to a key.
    Since the Context is associated with a thread it can be used to maintain values that can be later retrieved using the current thread.
    Note that the values are maintained with the Context, so if the Context is disassociated from the thread the values cannot be retreived. Also, if private data is to be maintained in this manner the key should be a java.lang.Object whose reference is not divulged to untrusted code.
    
    Parameters:
    
    key - the key used to lookup the value
    
    Returns:
    
    a value previously stored using putThreadLocal.
  - putThreadLocal
```
public void putThreadLocal(Object key,
                           Object value)
```
    Put a value that can later be retrieved using a given key.
    
    Parameters:
    
    key - the key used to index the value
    
    value - the value to save
  - removeThreadLocal
```
public void removeThreadLocal(Object key)
```
    Remove values from thread-local storage.
    
    Parameters:
    
    key - the key for the entry to remove.
    
    Since:
    
    1.5 release 2
  - hasCompileFunctionsWithDynamicScope
```
public final boolean hasCompileFunctionsWithDynamicScope()
```
    Return whether functions are compiled by this context using dynamic scope.
    If functions are compiled with dynamic scope, then they execute in the scope of their caller, rather than in their parent scope. This is useful for sharing functions across multiple scopes.
    
    Since:
    
    1.5 Release 1
  - setCompileFunctionsWithDynamicScope
```
public void setCompileFunctionsWithDynamicScope(boolean flag)
```
    Set whether functions compiled by this context should use dynamic scope.
    
    Parameters:
    
    flag - if true, compile functions with dynamic scope
    
    Since:
    
    1.5 Release 1
  - hasFeature
```
public boolean hasFeature(int featureIndex)
```
    Controls certain aspects of script semantics. Should be overwritten to alter default behavior.
    
    Parameters:
    
    featureIndex - feature index to check
    
    Returns:
    
    true if the featureIndex feature is turned on
    
    See Also:
    
    FEATURE_NON_ECMA_GET_YEAR, FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME, FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER, FEATURE_TO_STRING_AS_SOURCE

Class Context

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

languageVersionProperty

errorReporterProperty

VERSION_UNKNOWN

VERSION_DEFAULT

VERSION_1_0

VERSION_1_1

VERSION_1_2

VERSION_1_3

VERSION_1_4

VERSION_1_5

FEATURE_NON_ECMA_GET_YEAR

FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME

FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER

FEATURE_TO_STRING_AS_SOURCE

Constructor Detail

Context

Method Detail

enter

enter

exit

getCurrentContext

getLanguageVersion

setLanguageVersion

getImplementationVersion

getErrorReporter

setErrorReporter

getLocale

setLocale

reportWarning

reportError

getThreadLocal

putThreadLocal

removeThreadLocal

hasCompileFunctionsWithDynamicScope

setCompileFunctionsWithDynamicScope

hasFeature