Expression Language 3.0 API 3.0.0 · javax.el.ListELResolver

Modifier and Type	Field and Description
private boolean	isReadOnly
private static Class<?>	theUnmodifiableListClass

Access	Constructor and Description
public	ListELResolver() Creates a new read/write `ListELResolver`.
public	ListELResolver(boolean `true` if this resolver cannot modify lists; `false` otherwise. isReadOnly) Creates a new `ListELResolver` whose read-only status is determined by the given parameter.

Method Summary

Modifier and Type	Method and Description
public Class<?>	Returns: `null` if base is not a `List`; otherwise `Integer.class`. getCommonPropertyType(ELContext The context of this evaluation. context, Object The list to analyze. Only bases of type `List` are handled by this resolver. base) Implements abstract javax.el.ELResolver.getCommonPropertyType. If the base object is a list, returns the most general type that this resolver accepts for the `property` argument.
public Iterator<FeatureDescriptor>	Returns: `null`. getFeatureDescriptors(ELContext The context of this evaluation. context, Object The list. Only bases of type `List` are handled by this resolver. base) Implements abstract javax.el.ELResolver.getFeatureDescriptors. Always returns `null`, since there is no reason to iterate through set set of all integers.
public Class<?>	Returns: If the `propertyResolved` property of `ELContext` was set to `true`, then the most general acceptable type; otherwise undefined. getType(ELContext The context of this evaluation. context, Object The list to analyze. Only bases of type `List` are handled by this resolver. base, Object The index of the element in the list to return the acceptable type for. Will be coerced into an integer, but otherwise ignored by this resolver. property) Implements abstract javax.el.ELResolver.getType. If the base object is a list, returns the most general acceptable type for a value in this list.
public Object	Returns: If the `propertyResolved` property of `ELContext` was set to `true`, then the value at the given index or `null` if the index was out of bounds. Otherwise, undefined. getValue(ELContext The context of this evaluation. context, Object The list to be analyzed. Only bases of type `List` are handled by this resolver. base, Object The index of the value to be returned. Will be coerced into an integer. property) Implements abstract javax.el.ELResolver.getValue. If the base object is a list, returns the value at the given index.
public boolean	Returns: If the `propertyResolved` property of `ELContext` was set to `true`, then `true` if calling the `setValue` method will always fail or `false` if it is possible that such a call may succeed; otherwise undefined. isReadOnly(ELContext The context of this evaluation. context, Object The list to analyze. Only bases of type `List` are handled by this resolver. base, Object The index of the element in the list to return the acceptable type for. Will be coerced into an integer, but otherwise ignored by this resolver. property) Implements abstract javax.el.ELResolver.isReadOnly. If the base object is a list, returns whether a call to `setValue` will always fail.
public void	setValue(ELContext The context of this evaluation. context, Object The list to be modified. Only bases of type `List` are handled by this resolver. base, Object The index of the value to be set. Will be coerced into an integer. property, Object The value to be set at the given index. val) Implements abstract javax.el.ELResolver.setValue. If the base object is a list, attempts to set the value at the given index with the given value.
private int	toInteger(Object p)

Inherited from javax.el.ELResolver:: convertToType invoke

isReadOnly	back to summary
private boolean isReadOnly

theUnmodifiableListClass	back to summary
private static Class<?> theUnmodifiableListClass

ListELResolver	back to summary
public ListELResolver() Creates a new read/write `ListELResolver`.

ListELResolver	back to summary
public ListELResolver(boolean isReadOnly) Creates a new `ListELResolver` whose read-only status is determined by the given parameter. Parameters isReadOnly:boolean `true` if this resolver cannot modify lists; `false` otherwise.

Method Detail

getCommonPropertyType back to summary

getCommonPropertyType	back to summary
public Class<?> getCommonPropertyType(ELContext context, Object base) Implements abstract javax.el.ELResolver.getCommonPropertyType. If the base object is a list, returns the most general type that this resolver accepts for the `property` argument. Otherwise, returns `null`. Assuming the base is a `List`, this method will always return `Integer.class`. This is because `List`s accept integers as their index. Parameters context:ELContext The context of this evaluation. base:Object The list to analyze. Only bases of type `List` are handled by this resolver. Returns:Class<?> `null` if base is not a `List`; otherwise `Integer.class`.

public Class<?> getCommonPropertyType(ELContext context, Object base)

Implements abstract javax.el.ELResolver.getCommonPropertyType.

If the base object is a list, returns the most general type that this resolver accepts for the property argument. Otherwise, returns null.

Assuming the base is a List, this method will always return Integer.class. This is because Lists accept integers as their index.

Parameters

context:ELContext: The context of this evaluation.
base:Object: The list to analyze. Only bases of type List are handled by this resolver.

Returns:Class<?>

null if base is not a List; otherwise Integer.class.

getFeatureDescriptors back to summary

getFeatureDescriptors	back to summary
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) Implements abstract javax.el.ELResolver.getFeatureDescriptors. Always returns `null`, since there is no reason to iterate through set set of all integers. The `getCommonPropertyType` method returns sufficient information about what properties this resolver accepts. Parameters context:ELContext The context of this evaluation. base:Object The list. Only bases of type `List` are handled by this resolver. Returns:Iterator<FeatureDescriptor> `null`.

public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base)

Implements abstract javax.el.ELResolver.getFeatureDescriptors.

Always returns null, since there is no reason to iterate through set set of all integers.

The getCommonPropertyType method returns sufficient information about what properties this resolver accepts.

Parameters

context:ELContext: The context of this evaluation.
base:Object: The list. Only bases of type List are handled by this resolver.

Returns:Iterator<FeatureDescriptor>

null.

getType back to summary

getType	back to summary
public Class<?> getType(ELContext context, Object base, Object property) Implements abstract javax.el.ELResolver.getType. If the base object is a list, returns the most general acceptable type for a value in this list. If the base is a `List`, the `propertyResolved` property of the `ELContext` object must be set to `true` by this resolver, before returning. If this property is not `true` after this method is called, the caller should ignore the return value. Assuming the base is a `List`, this method will always return `Object.class`. This is because `List`s accept any object as an element. Parameters context:ELContext The context of this evaluation. base:Object The list to analyze. Only bases of type `List` are handled by this resolver. property:Object The index of the element in the list to return the acceptable type for. Will be coerced into an integer, but otherwise ignored by this resolver. Returns:Class<?> If the `propertyResolved` property of `ELContext` was set to `true`, then the most general acceptable type; otherwise undefined. Exceptions PropertyNotFoundException: if the given index is out of bounds for this list. NullPointerException: if context is `null` 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.

public Class<?> getType(ELContext context, Object base, Object property)

Implements abstract javax.el.ELResolver.getType.

If the base object is a list, returns the most general acceptable type for a value in this list.

If the base is a List, the propertyResolved property of the ELContext object must be set to true by this resolver, before returning. If this property is not true after this method is called, the caller should ignore the return value.

Assuming the base is a List, this method will always return Object.class. This is because Lists accept any object as an element.

Parameters

context:ELContext: The context of this evaluation.
base:Object: The list to analyze. Only bases of type List are handled by this resolver.
property:Object: The index of the element in the list to return the acceptable type for. Will be coerced into an integer, but otherwise ignored by this resolver.

Returns:Class<?>

If the propertyResolved property of ELContext was set to true, then the most general acceptable type; otherwise undefined.

Exceptions

PropertyNotFoundException:: if the given index is out of bounds for this list.
NullPointerException:: if context is null
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.

getValue back to summary

getValue	back to summary
public Object getValue(ELContext context, Object base, Object property) Implements abstract javax.el.ELResolver.getValue. If the base object is a list, returns the value at the given index. The index is specified by the `property` argument, and coerced into an integer. If the coercion could not be performed, an `IllegalArgumentException` is thrown. If the index is out of bounds, `null` is returned. If the base is a `List`, the `propertyResolved` property of the `ELContext` object must be set to `true` by this resolver, before returning. If this property is not `true` after this method is called, the caller should ignore the return value. Parameters context:ELContext The context of this evaluation. base:Object The list to be analyzed. Only bases of type `List` are handled by this resolver. property:Object The index of the value to be returned. Will be coerced into an integer. Returns:Object If the `propertyResolved` property of `ELContext` was set to `true`, then the value at the given index or `null` if the index was out of bounds. Otherwise, undefined. Exceptions IllegalArgumentException: if the property could not be coerced into an integer. NullPointerException: if context is `null`. 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.

public Object getValue(ELContext context, Object base, Object property)

Implements abstract javax.el.ELResolver.getValue.

If the base object is a list, returns the value at the given index. The index is specified by the property argument, and coerced into an integer. If the coercion could not be performed, an IllegalArgumentException is thrown. If the index is out of bounds, null is returned.

Parameters

context:ELContext: The context of this evaluation.
base:Object: The list to be analyzed. Only bases of type List are handled by this resolver.
property:Object: The index of the value to be returned. Will be coerced into an integer.

Returns:Object

If the propertyResolved property of ELContext was set to true, then the value at the given index or null if the index was out of bounds. Otherwise, undefined.

Exceptions

IllegalArgumentException:: if the property could not be coerced into an integer.
NullPointerException:: if context is null.
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.

isReadOnly back to summary

isReadOnly	back to summary
public boolean isReadOnly(ELContext context, Object base, Object property) Implements abstract javax.el.ELResolver.isReadOnly. If the base object is a list, returns whether a call to `setValue` will always fail. If the base is a `List`, the `propertyResolved` property of the `ELContext` object must be set to `true` by this resolver, before returning. If this property is not `true` after this method is called, the caller should ignore the return value. If this resolver was constructed in read-only mode, this method will always return `true`. If a `List` was created using `java.util.Collections#unmodifiableList`, this method must return `true`. Unfortunately, there is no Collections API method to detect this. However, an implementation can create a prototype unmodifiable `List` and query its runtime type to see if it matches the runtime type of the base object as a workaround. Parameters context:ELContext The context of this evaluation. base:Object The list to analyze. Only bases of type `List` are handled by this resolver. property:Object The index of the element in the list to return the acceptable type for. Will be coerced into an integer, but otherwise ignored by this resolver. Returns:boolean If the `propertyResolved` property of `ELContext` was set to `true`, then `true` if calling the `setValue` method will always fail or `false` if it is possible that such a call may succeed; otherwise undefined. Exceptions PropertyNotFoundException: if the given index is out of bounds for this list. NullPointerException: if context is `null` 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.

public boolean isReadOnly(ELContext context, Object base, Object property)

Implements abstract javax.el.ELResolver.isReadOnly.

If the base object is a list, returns whether a call to setValue will always fail.

If this resolver was constructed in read-only mode, this method will always return true.

If a List was created using java.util.Collections#unmodifiableList, this method must return true. Unfortunately, there is no Collections API method to detect this. However, an implementation can create a prototype unmodifiable List and query its runtime type to see if it matches the runtime type of the base object as a workaround.

Parameters

context:ELContext: The context of this evaluation.
base:Object: The list to analyze. Only bases of type List are handled by this resolver.
property:Object: The index of the element in the list to return the acceptable type for. Will be coerced into an integer, but otherwise ignored by this resolver.

Returns:boolean

If the propertyResolved property of ELContext was set to true, then true if calling the setValue method will always fail or false if it is possible that such a call may succeed; otherwise undefined.

Exceptions

PropertyNotFoundException:: if the given index is out of bounds for this list.
NullPointerException:: if context is null
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.

setValue back to summary

setValue	back to summary
public void setValue(ELContext context, Object base, Object property, Object val) Implements abstract javax.el.ELResolver.setValue. If the base object is a list, attempts to set the value at the given index with the given value. The index is specified by the `property` argument, and coerced into an integer. If the coercion could not be performed, an `IllegalArgumentException` is thrown. If the index is out of bounds, a `PropertyNotFoundException` is thrown. If the base is a `List`, the `propertyResolved` property of the `ELContext` object must be set to `true` by this resolver, before returning. If this property is not `true` after this method is called, the caller can safely assume no value was set. If this resolver was constructed in read-only mode, this method will always throw `PropertyNotWritableException`. If a `List` was created using `java.util.Collections#unmodifiableList`, this method must throw `PropertyNotWritableException`. Unfortunately, there is no Collections API method to detect this. However, an implementation can create a prototype unmodifiable `List` and query its runtime type to see if it matches the runtime type of the base object as a workaround. Parameters context:ELContext The context of this evaluation. base:Object The list to be modified. Only bases of type `List` are handled by this resolver. property:Object The index of the value to be set. Will be coerced into an integer. val:Object The value to be set at the given index. Exceptions ClassCastException: if the class of the specified element prevents it from being added to this list. NullPointerException: if context is `null`, or if the value is `null` and this `List` does not support `null` elements. IllegalArgumentException: if the property could not be coerced into an integer, or if some aspect of the specified element prevents it from being added to this list. PropertyNotWritableException: if this resolver was constructed in read-only mode, or if the set operation is not supported by the underlying list. PropertyNotFoundException: if the given index is out of bounds for this list. 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.

public void setValue(ELContext context, Object base, Object property, Object val)

Implements abstract javax.el.ELResolver.setValue.

If the base object is a list, attempts to set the value at the given index with the given value. The index is specified by the property argument, and coerced into an integer. If the coercion could not be performed, an IllegalArgumentException is thrown. If the index is out of bounds, a PropertyNotFoundException is thrown.

If this resolver was constructed in read-only mode, this method will always throw PropertyNotWritableException.

If a List was created using java.util.Collections#unmodifiableList, this method must throw PropertyNotWritableException. Unfortunately, there is no Collections API method to detect this. However, an implementation can create a prototype unmodifiable List and query its runtime type to see if it matches the runtime type of the base object as a workaround.

Parameters

context:ELContext: The context of this evaluation.
base:Object: The list to be modified. Only bases of type List are handled by this resolver.
property:Object: The index of the value to be set. Will be coerced into an integer.
val:Object: The value to be set at the given index.

Exceptions

ClassCastException:: if the class of the specified element prevents it from being added to this list.
NullPointerException:: if context is null, or if the value is null and this List does not support null elements.
IllegalArgumentException:: if the property could not be coerced into an integer, or if some aspect of the specified element prevents it from being added to this list.
PropertyNotWritableException:: if this resolver was constructed in read-only mode, or if the set operation is not supported by the underlying list.
PropertyNotFoundException:: if the given index is out of bounds for this list.
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.

toInteger	back to summary
private int toInteger(Object p)

public Class ListELResolver

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