/// <summary>
/// Parses an expression into a <seealso cref="ValueExpression" /> for later evaluation. Use this method for
/// expressions that refer to values. This method should perform syntactic validation of the
/// expression. If in doing so it detects errors, it should raise an ELException.
/// </summary>
/// <param name="context">
/// The EL context used to parse the expression. The FunctionMapper and VariableMapper
/// stored in the ELContext are used to resolve functions and variables found in the
/// expression. They can be null, in which case functions or variables are not
/// supported for this expression. The object returned must invoke the same functions
/// and access the same variable mappings regardless of whether the mappings in the
/// provided FunctionMapper and VariableMapper instances change between calling
/// ExpressionFactory.createValueExpression() and any method on ValueExpression. Note
/// that within the EL, the ${} and #{} syntaxes are treated identically. This
/// includes the use of VariableMapper and FunctionMapper at expression creation time.
/// Each is invoked if not null, independent of whether the #{} or ${} syntax is used
/// for the expression.
/// </param>
/// <param name="expression">
/// The expression to parse
/// </param>
/// <param name="expectedType">
/// The type the result of the expression will be coerced to after evaluation.
/// </param>
/// <returns> The parsed expression </returns>
/// <exception cref="ELException">
/// Thrown if there are syntactical errors in the provided expression.
/// </exception>
/// <exception cref="NullPointerException">
/// if paramTypes is null.
/// </exception>
public abstract ValueExpression CreateValueExpression(ELContext context, string expression, Type expectedType);
/// <summary> /// Evaluates the expression relative to the provided context, and returns the resulting value. /// The resulting value is automatically coerced to the type returned by getExpectedType(), which /// was provided to the ExpressionFactory when this expression was created. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <returns> The result of the expression evaluation. </returns> /// <exception cref="NullPointerException"> /// if context is null. /// </exception> /// <exception cref="PropertyNotFoundException"> /// if one of the property resolutions failed because a specified variable or /// property does not exist or is not readable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing property or variable resolution. The /// thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract object GetValue(ELContext context);
/// <summary> /// If a String literal is specified as the expression, returns the String literal coerced to the /// expected return type of the method signature. An ELException is thrown if expectedReturnType /// is void or if the coercion of the String literal to the expectedReturnType yields an error /// (see Section "1.16 Type Conversion" of the EL specification). If not a String literal, /// evaluates the expression relative to the provided context, invokes the method that was found /// using the supplied parameters, and returns the result of the method invocation. Any /// parameters passed to this method is ignored if isLiteralText() is true. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="params"> /// The parameters to pass to the method, or null if no parameters. /// </param> /// <returns> the result of the method invocation (null if the method has a void return type). </returns> /// <exception cref="NullPointerException"> /// if context is null /// </exception> /// <exception cref="PropertyNotFoundException"> /// if one of the property resolutions failed because a specified variable or /// property does not exist or is not readable. /// </exception> /// <exception cref="MethodNotFoundException"> /// if no suitable method can be found. /// </exception> /// <exception cref="ELException"> /// if a String literal is specified and expectedReturnType of the MethodExpression /// is void or if the coercion of the String literal to the expectedReturnType yields /// an error (see Section "1.16 Type Conversion"). /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing property or variable resolution. The /// thrown exception must be included as the cause property of this exception, if /// available. If the exception thrown is an TargetInvocationException, extract its /// cause and pass it to the ELException constructor. /// </exception> public abstract object Invoke(ELContext context, object[] @params);
/// <summary>
/// If the base object is not null, returns the most general type that this resolver accepts for
/// the property argument. Otherwise, returns null. Assuming the base is not null, this method
/// will always return Object.class. This is because any object is accepted as a key and is
/// coerced into a string.
/// </summary>
/// <param name="context">
/// The context of this evaluation. </param>
/// <param name="base">
/// The Object to analyze. </param>
/// <returns> null if base is null; otherwise Object.class. </returns>
public override Type GetCommonPropertyType(ELContext context, object @base)
{
return(IsResolvable(@base) ? typeof(object) : null);
}
public override Type GetType(ELContext arg0, object arg1, object arg2)
{
return(typeof(object));
}
public override Type GetType(ELContext context, object @base, object property)
{
return(typeof(object));
}
/// <summary>
/// Attempts to resolve and invoke the given <code>method</code> on the given <code>base</code>
/// object.
/// <para>
/// If this resolver handles the given (base, method) pair, the <code>propertyResolved</code>
/// property of the <code>ELContext</code> object must be set to <code>true</code> by the
/// resolver, before returning. If this property is not <code>true</code> after this method is
/// called, the caller should ignore the return value.
/// </para>
/// <para>
/// A default implementation is provided that returns null so that existing classes that extend
/// ELResolver can continue to function.
/// </para>
/// </summary>
/// <param name="context">
/// The context of this evaluation.
/// </param>
/// <param name="base">
/// The bean on which to invoke the method
/// </param>
/// <param name="method">
/// The simple name of the method to invoke. Will be coerced to a <code>String</code>.
/// </param>
/// <param name="paramTypes">
/// An array of Class objects identifying the method's formal parameter types, in
/// declared order. Use an empty array if the method has no parameters. Can be
/// <code>null</code>, in which case the method's formal parameter types are assumed
/// to be unknown.
/// </param>
/// <param name="params">
/// The parameters to pass to the method, or <code>null</code> if no parameters.
/// </param>
/// <returns>
/// The result of the method invocation (<code>null</code> if the method has a
/// <code>void</code> return type).
/// </returns>
/// <exception cref="MethodNotFoundException">
/// if no suitable method can be found.
/// </exception>
/// <exception cref="ELException">
/// if an exception was thrown while performing (base, method) resolution. The thrown
/// exception must be included as the cause property of this exception, if available.
/// If the exception thrown is an <code>TargetInvocationException</code>, extract its
/// <code>cause</code> and pass it to the <code>ELException</code> constructor.
/// </exception>
public virtual object Invoke(ELContext context, object @base, object method, Type[] paramTypes, object[] @params)
{
return(null);
}
public override Type GetCommonPropertyType(ELContext arg0, object arg1)
{
return(typeof(object));
}
/// <summary> /// For a given base and property, attempts to determine whether a call to /// <seealso cref=".setValue(ELContext, Object, Object, Object)" /> will always fail. If this resolver /// handles the given (base, property) pair, the propertyResolved property of the ELContext /// object must be set to true by the resolver, before returning. If this property is not true /// after this method is called, the caller should ignore the return value. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="base"> /// The base object whose property value is to be analyzed, or null to analyze a /// top-level variable. /// </param> /// <param name="property"> /// The property or variable to return the read-only status for. /// </param> /// <returns> /// If the propertyResolved property of ELContext was set to true, then true if the /// property is read-only or false if not; otherwise undefined. /// </returns> /// <exception cref="NullPointerException"> /// if context is null /// </exception> /// <exception cref="PropertyNotFoundException"> /// if the given (base, property) pair is handled by this ELResolver but the /// specified variable or property does not exist. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing the property or variable resolution. /// The thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract bool IsReadOnly(ELContext context, object @base, object property);
/// <summary> /// Attempts to set the value of the given property object on the given base object. If this /// resolver handles the given (base, property) pair, the propertyResolved property of the /// ELContext object must be set to true by the resolver, before returning. If this property is /// not true after this method is called, the caller can safely assume no value has been set. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="base"> /// The base object whose property value is to be set, or null to set a top-level /// variable. /// </param> /// <param name="property"> /// The property or variable to be set. /// </param> /// <param name="value"> /// The value to set the property or variable to. /// </param> /// <exception cref="NullPointerException"> /// if context is null /// </exception> /// <exception cref="PropertyNotFoundException"> /// if the given (base, property) pair is handled by this ELResolver but the /// specified variable or property does not exist. /// </exception> /// <exception cref="PropertyNotWritableException"> /// if the given (base, property) pair is handled by this ELResolver but the /// specified variable or property is not writable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while attempting to set the property or variable. The /// thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract void SetValue(ELContext context, object @base, object property, object value);
/// <summary> /// Attempts to resolve the given property object on the given base object. If this resolver /// handles the given (base, property) pair, the propertyResolved property of the ELContext /// object must be set to true by the resolver, before returning. If this property is not true /// after this method is called, the caller should ignore the return value. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="base"> /// The base object whose property value is to be returned, or null to resolve a /// top-level variable. /// </param> /// <param name="property"> /// The property or variable to be resolved. /// </param> /// <returns> /// If the propertyResolved property of ELContext was set to true, then the result of the /// variable or property resolution; otherwise undefined. /// </returns> /// <exception cref="NullPointerException"> /// if context is null /// </exception> /// <exception cref="PropertyNotFoundException"> /// if the given (base, property) pair is handled by this ELResolver but the /// specified variable or property does not exist or is not readable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing the property or variable resolution. /// The thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract object GetValue(ELContext context, object @base, object property);
/// <summary> /// Returns information about the set of variables or properties that can be resolved for the /// given base object. One use for this method is to assist tools in auto-completion. If the base /// parameter is null, the resolver must enumerate the list of top-level variables it can /// resolve. The Iterator returned must contain zero or more instances of /// java.beans.MemberDescriptor, in no guaranteed order. In the case of primitive types such as /// int, the value null must be returned. This is to prevent the useless iteration through all /// possible primitive values. A return value of null indicates that this resolver does not /// handle the given base object or that the results are too complex to represent with this /// method and the <seealso cref=".getCommonPropertyType(ELContext, Object)" /> method should be used /// instead. Each MemberDescriptor will contain information about a single variable or property. /// In addition to the standard properties, the MemberDescriptor must have two named attributes /// (as set by the setValue method): /// <ul> /// <li> /// <seealso cref=".TYPE" /> - The value of this named attribute must be an instance of java.lang.Class /// and specify the runtime type of the variable or property. /// </li> /// <li> /// <seealso cref=".RESOLVABLE_AT_DESIGN_TIME" /> - The value of this named attribute must be an /// instance of java.lang.Boolean and indicates whether it is safe to attempt to resolve this /// property at designtime. For instance, it may be unsafe to attempt a resolution at design time /// if the ELResolver needs access to a resource that is only available at runtime and no /// acceptable simulated value can be provided. /// </li> /// </ul> /// The caller should be aware that the Iterator returned might iterate through a very large or /// even infinitely large set of properties. Care should be taken by the caller to not get stuck /// in an infinite loop. This is a "best-effort" list. Not all ELResolvers will return completely /// accurate results, but all must be callable at both design-time and runtime (i.e. whether or /// not Beans.isDesignTime() returns true), without causing errors. The propertyResolved property /// of the ELContext is not relevant to this method. The results of all ELResolvers are /// concatenated in the case of composite resolvers. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="base"> /// The base object whose set of valid properties is to be enumerated, or null to /// enumerate the set of top-level variables that this resolver can evaluate. /// </param> /// <returns> /// An Iterator containing zero or more (possibly infinitely more) MemberDescriptor /// objects, or null if this resolver does not handle the given base object or that the /// results are too complex to represent with this method /// </returns> /// <summary> /// For a given base and property, attempts to identify the most general type that is acceptable /// for an object to be passed as the value parameter in a future call to the /// <seealso cref=".setValue(ELContext, Object, Object, Object)" /> method. If this resolver handles the /// given (base, property) pair, the propertyResolved property of the ELContext object must be /// set to true by the resolver, before returning. If this property is not true after this method /// is called, the caller should ignore the return value. This is not always the same as /// getValue().getClass(). For example, in the case of an <seealso cref="ArrayELResolver" />, the getType /// method will return the element type of the array, which might be a superclass of the type of /// the actual element that is currently in the specified array element. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="base"> /// The base object whose property value is to be analyzed, or null to analyze a /// top-level variable. /// </param> /// <param name="property"> /// The property or variable to return the acceptable type for. /// </param> /// <returns> /// If the propertyResolved property of ELContext was set to true, then the most general /// acceptable type; otherwise undefined. /// </returns> /// <exception cref="java.lang.NullPointerException"> /// if context is null /// </exception> /// <exception cref="PropertyNotFoundException"> /// if the given (base, property) pair is handled by this ELResolver but the /// specified variable or property does not exist or is not readable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing the property or variable resolution. /// The thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract Type GetType(ELContext context, object @base, object property);
/// <summary> /// Returns information about the set of variables or properties that can be resolved for the /// given base object. One use for this method is to assist tools in auto-completion. If the base /// parameter is null, the resolver must enumerate the list of top-level variables it can /// resolve. The Iterator returned must contain zero or more instances of /// java.beans.FeatureDescriptor, in no guaranteed order. In the case of primitive types such as /// int, the value null must be returned. This is to prevent the useless iteration through all /// possible primitive values. A return value of null indicates that this resolver does not /// handle the given base object or that the results are too complex to represent with this /// method and the <seealso cref=".getCommonPropertyType(ELContext, Object)"/> method should be used /// instead. Each FeatureDescriptor will contain information about a single variable or property. /// In addition to the standard properties, the FeatureDescriptor must have two named attributes /// (as set by the setValue method): /// <ul> /// <li><seealso cref=".TYPE"/> - The value of this named attribute must be an instance of java.lang.Class /// and specify the runtime type of the variable or property.</li> /// <li><seealso cref=".RESOLVABLE_AT_DESIGN_TIME"/> - The value of this named attribute must be an /// instance of java.lang.Boolean and indicates whether it is safe to attempt to resolve this /// property at designtime. For instance, it may be unsafe to attempt a resolution at design time /// if the ELResolver needs access to a resource that is only available at runtime and no /// acceptable simulated value can be provided.</li> /// </ul> /// The caller should be aware that the Iterator returned might iterate through a very large or /// even infinitely large set of properties. Care should be taken by the caller to not get stuck /// in an infinite loop. This is a "best-effort" list. Not all ELResolvers will return completely /// accurate results, but all must be callable at both design-time and runtime (i.e. whether or /// not Beans.isDesignTime() returns true), without causing errors. The propertyResolved property /// of the ELContext is not relevant to this method. The results of all ELResolvers are /// concatenated in the case of composite resolvers. /// </summary> /// <param name="context"> /// The context of this evaluation. </param> /// <param name="base"> /// The base object whose set of valid properties is to be enumerated, or null to /// enumerate the set of top-level variables that this resolver can evaluate. </param> /// <returns> An Iterator containing zero or more (possibly infinitely more) FeatureDescriptor /// objects, or null if this resolver does not handle the given base object or that the /// results are too complex to represent with this method </returns> public abstract IEnumerator <MemberInfo> GetMemberInfos(ELContext context, object @base);
public override void SetValue(ELContext context, object @base, object property, object value)
{
// read only
}
/// <summary> /// Returns the most general type that this resolver accepts for the property argument, given a /// base object. One use for this method is to assist tools in auto-completion. This assists /// tools in auto-completion and also provides a way to express that the resolver accepts a /// primitive value, such as an integer index into an array. For example, the /// <seealso cref="ArrayELResolver" /> will accept any int as a property, so the return value would be /// Integer.class. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="base"> /// The base object to return the most general property type for, or null to enumerate /// the set of top-level variables that this resolver can evaluate. /// </param> /// <returns> /// null if this ELResolver does not know how to handle the given base object; otherwise /// Object.class if any type of property is accepted; otherwise the most general property /// type accepted for the given base. /// </returns> public abstract Type GetCommonPropertyType(ELContext context, object @base);
public override bool IsReadOnly(ELContext context, object @base, object property)
{
// always read only
return(true);
}
public override void SetValue(ELContext context, object @base, object property, object value)
{
throw new NotImplementedException();
}
public override IEnumerator <MemberInfo> GetMemberInfos(ELContext arg0, object arg1)
{
return(null);
}
/// <summary> /// Evaluates the expression relative to the provided context, and returns true if a call to /// <seealso cref="#setValue(ELContext, Object)" /> will always fail. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <returns> true if the expression is read-only or false if not. </returns> /// <exception cref="NullPointerException"> /// if context is null. /// </exception> /// <exception cref="PropertyNotFoundException"> /// if one of the property resolutions failed because a specified variable or /// property does not exist or is not readable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing property or variable resolution. The /// thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract bool IsReadOnly(ELContext context);
public override IEnumerator <MemberInfo> GetMemberInfos(ELContext context, object @base)
{
return(null);
}
/// <summary> /// Evaluates the expression relative to the provided context, and sets the result to the /// provided value. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <param name="value"> /// The new value to be set. /// </param> /// <exception cref="NullPointerException"> /// if context is null. /// </exception> /// <exception cref="PropertyNotFoundException"> /// if one of the property resolutions failed because a specified variable or /// property does not exist or is not readable. /// </exception> /// <exception cref="PropertyNotWritableException"> /// if the final variable or property resolution failed because the specified /// variable or property is not writable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while attempting to set the property or variable. The /// thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract void SetValue(ELContext context, object value);
public override bool IsReadOnly(ELContext context, object @base, object property)
{
return(ReadOnly);
}
/// <summary>
/// Returns a <seealso cref="ValueReference" /> for this expression instance.
/// </summary>
/// <param name="context">
/// the context of this evaluation
/// </param>
/// <returns>
/// the <code>ValueReference</code> for this <code>ValueExpression</code>, or
/// <code>null</code> if this <code>ValueExpression</code> is not a reference to a base
/// (null or non-null) and a property. If the base is null, and the property is a EL
/// variable, return the <code>ValueReference</code> for the <code>ValueExpression</code>
/// associated with this EL variable.
///
/// </returns>
public virtual ValueReference GetValueReference(ELContext context)
{
return(null);
}
/// <summary> /// Evaluates the expression relative to the provided context, and returns information about the /// actual referenced method. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <returns> The context of this evaluation </returns> /// <exception cref="NullPointerException"> /// if context is null /// </exception> /// <exception cref="PropertyNotFoundException"> /// if one of the property resolutions failed because a specified variable or /// property does not exist or is not readable. /// </exception> /// <exception cref="MethodNotFoundException"> /// if no suitable method can be found. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing property or variable resolution. The /// thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract MethodInfo GetMethodInfo(ELContext context);
/// <summary> /// Evaluates the expression relative to the provided context, and returns the most general type /// that is acceptable for an object to be passed as the value parameter in a future call to the /// <seealso cref="#setValue(ELContext, Object)" /> method. This is not always the same as /// getValue().getClass(). For example, in the case of an expression that references an array /// element, the getType method will return the element type of the array, which might be a /// superclass of the type of the actual element that is currently in the specified array /// element. /// </summary> /// <param name="context"> /// The context of this evaluation. /// </param> /// <returns> the most general acceptable type; otherwise undefined. </returns> /// <exception cref="NullPointerException"> /// if context is null. /// </exception> /// <exception cref="PropertyNotFoundException"> /// if one of the property resolutions failed because a specified variable or /// property does not exist or is not readable. /// </exception> /// <exception cref="ELException"> /// if an exception was thrown while performing property or variable resolution. The /// thrown exception must be included as the cause property of this exception, if /// available. /// </exception> public abstract Type GetType(ELContext context);
/// <summary>
/// Returns information about the set of variables or properties that can be resolved for the
/// given base object. One use for this method is to assist tools in auto-completion. The results
/// are collected from all component resolvers. The propertyResolved property of the ELContext is
/// not relevant to this method. The results of all ELResolvers are concatenated. The Iterator
/// returned is an iterator over the collection of FeatureDescriptor objects returned by the
/// iterators returned by each component resolver's getFeatureDescriptors method. If null is
/// returned by a resolver, it is skipped.
/// </summary>
/// <param name="context">
/// The context of this evaluation. </param>
/// <param name="base">
/// The base object to return the most general property type for, or null to enumerate
/// the set of top-level variables that this resolver can evaluate. </param>
/// <returns> An Iterator containing zero or more (possibly infinitely more) FeatureDescriptor
/// objects, or null if this resolver does not handle the given base object or that the
/// results are too complex to represent with this method </returns>
public override IEnumerator <MemberInfo> GetMemberInfos(ELContext context, object @base)
{
return(null);
//return new IteratorAnonymousInnerClass(this, context, @base);
}
/// <summary>
/// Parses an expression into a <seealso cref="MethodExpression" /> for later evaluation. Use this method
/// for expressions that refer to methods. If the expression is a String literal, a
/// MethodExpression is created, which when invoked, returns the String literal, coerced to
/// expectedReturnType. An ELException is thrown if expectedReturnType is void or if the coercion
/// of the String literal to the expectedReturnType yields an error (see Section "1.16 Type
/// Conversion"). This method should perform syntactic validation of the expression. If in doing
/// so it detects errors, it should raise an ELException.
/// </summary>
/// <param name="context">
/// The EL context used to parse the expression. The FunctionMapper and VariableMapper
/// stored in the ELContext are used to resolve functions and variables found in the
/// expression. They can be null, in which case functions or variables are not
/// supported for this expression. The object returned must invoke the same functions
/// and access the same variable mappings regardless of whether the mappings in the
/// provided FunctionMapper and VariableMapper instances change between calling
/// ExpressionFactory.createMethodExpression() and any method on MethodExpression.
/// Note that within the EL, the ${} and #{} syntaxes are treated identically. This
/// includes the use of VariableMapper and FunctionMapper at expression creation time.
/// Each is invoked if not null, independent of whether the #{} or ${} syntax is used
/// for the expression.
/// </param>
/// <param name="expression">
/// The expression to parse
/// </param>
/// <param name="expectedReturnType">
/// The expected return type for the method to be found. After evaluating the
/// expression, the MethodExpression must check that the return type of the actual
/// method matches this type. Passing in a value of null indicates the caller does not
/// care what the return type is, and the check is disabled.
/// </param>
/// <param name="expectedParamTypes">
/// The expected parameter types for the method to be found. Must be an array with no
/// elements if there are no parameters expected. It is illegal to pass null.
/// </param>
/// <returns> The parsed expression </returns>
/// <exception cref="ELException">
/// Thrown if there are syntactical errors in the provided expression.
/// </exception>
/// <exception cref="NullPointerException">
/// if paramTypes is null.
/// </exception>
public abstract MethodExpression CreateMethodExpression(ELContext context, string expression,
Type expectedReturnType, Type[] expectedParamTypes);
