Java Property.NOT_WRITABLE属性代码示例

private ScriptObject createNashornGlobal(final ScriptContext ctxt) {
    final ScriptObject newGlobal = AccessController.doPrivileged(new PrivilegedAction<ScriptObject>() {
        @Override
        public ScriptObject run() {
            try {
                return nashornContext.newGlobal();
            } catch (final RuntimeException e) {
                if (Context.DEBUG) {
                    e.printStackTrace();
                }
                throw e;
            }
        }
    }, CREATE_GLOBAL_ACC_CTXT);

    nashornContext.initGlobal(newGlobal);

    final int NON_ENUMERABLE_CONSTANT = Property.NOT_ENUMERABLE | Property.NOT_CONFIGURABLE | Property.NOT_WRITABLE;
    // current ScriptContext exposed as "context"
    // "context" is non-writable from script - but script engine still
    // needs to set it and so save the context Property object
    contextProperty = newGlobal.addOwnProperty("context", NON_ENUMERABLE_CONSTANT, ctxt);
    // current ScriptEngine instance exposed as "engine". We added @SuppressWarnings("LeakingThisInConstructor") as
    // NetBeans identifies this assignment as such a leak - this is a false positive as we're setting this property
    // in the Global of a Context we just created - both the Context and the Global were just created and can not be
    // seen from another thread outside of this constructor.
    newGlobal.addOwnProperty("engine", NON_ENUMERABLE_CONSTANT, this);
    // global script arguments with undefined value
    newGlobal.addOwnProperty("arguments", Property.NOT_ENUMERABLE, UNDEFINED);
    // file name default is null
    newGlobal.addOwnProperty(ScriptEngine.FILENAME, Property.NOT_ENUMERABLE, null);
    // evaluate engine.js initialization script this new global object
    try {
        evalImpl(compileImpl(ENGINE_SCRIPT_SRC, newGlobal), ctxt, newGlobal);
    } catch (final ScriptException exp) {
        throw new RuntimeException(exp);
    }
    return newGlobal;
}
 

/**
 * Compute property flags given local state of a field. May be overridden and extended,
 *
 * @param symbol       symbol to check
 * @param hasArguments does the created object have an "arguments" property
 *
 * @return flags to use for fields
 */
static int getPropertyFlags(final Symbol symbol, final boolean hasArguments, final boolean evalCode) {
    int flags = 0;

    if (symbol.isParam()) {
        flags |= Property.IS_PARAMETER;
    }

    if (hasArguments) {
        flags |= Property.HAS_ARGUMENTS;
    }

    // See ECMA 5.1 10.5 Declaration Binding Instantiation.
    // Step 2  If code is eval code, then let configurableBindings
    // be true else let configurableBindings be false.
    // We have to make vars, functions declared in 'eval' code
    // configurable. But vars, functions from any other code is
    // not configurable.
    if (symbol.isScope() && !evalCode) {
        flags |= Property.NOT_CONFIGURABLE;
    }

    if (symbol.isFunctionDeclaration()) {
        flags |= Property.IS_FUNCTION_DECLARATION;
    }

    if (symbol.isConst()) {
        flags |= Property.NOT_WRITABLE;
    }

    if (symbol.isBlockScoped()) {
        flags |= Property.IS_LEXICAL_BINDING;
    }

    // Mark symbol as needing declaration. Access before declaration will throw a ReferenceError.
    if (symbol.isBlockScoped() && symbol.isScope()) {
        flags |= Property.NEEDS_DECLARATION;
    }

    return flags;
}
 

/**
 * Compute property flags given local state of a field. May be overridden and extended,
 *
 * @param symbol       symbol to check
 * @param hasArguments does the created object have an "arguments" property
 *
 * @return flags to use for fields
 */
static int getPropertyFlags(final Symbol symbol, final boolean hasArguments, final boolean evalCode, final boolean dualFields) {
    int flags = 0;

    if (symbol.isParam()) {
        flags |= Property.IS_PARAMETER;
    }

    if (hasArguments) {
        flags |= Property.HAS_ARGUMENTS;
    }

    // See ECMA 5.1 10.5 Declaration Binding Instantiation.
    // Step 2  If code is eval code, then let configurableBindings
    // be true else let configurableBindings be false.
    // We have to make vars, functions declared in 'eval' code
    // configurable. But vars, functions from any other code is
    // not configurable.
    if (symbol.isScope() && !evalCode) {
        flags |= Property.NOT_CONFIGURABLE;
    }

    if (symbol.isFunctionDeclaration()) {
        flags |= Property.IS_FUNCTION_DECLARATION;
    }

    if (symbol.isConst()) {
        flags |= Property.NOT_WRITABLE;
    }

    if (symbol.isBlockScoped()) {
        flags |= Property.IS_LEXICAL_BINDING;
    }

    // Mark symbol as needing declaration. Access before declaration will throw a ReferenceError.
    if (symbol.isBlockScoped() && symbol.isScope()) {
        flags |= Property.NEEDS_DECLARATION;
    }

    if (dualFields) {
        flags |= Property.DUAL_FIELDS;
    }

    return flags;
}