Predicates (saxon JavaDoc)

java.lang.Object
- net.sf.saxon.s9api.streams.Predicates

```
public class Predicates
extends Object
```
This non-instantiable class provides a number of useful implementations of the Predicate interface, designed for use when navigating streams of XDM items.

Constructor Summary

Constructors
Constructor and Description

Predicates()

Constructors
Constructor and Description
`Predicates()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static Predicate<XdmNode>`	`attributeEq(String local, String value)` Obtain a predicate that tests whether an item is an element node with a given attribute (whose name is in no namespace) whose string value is equal to a given value
`static <T extends XdmItem> Predicate<XdmItem>`	`empty(Step<T> step)` Obtain a predicate that tests whether a supplied `Step` delivers an empty result
`static <T extends XdmItem> Predicate<XdmItem>`	`eq(Step<T> step, String value)` Obtain a predicate that tests whether there is some item in the result of applying a step, whose string value is equal to a given string.
`static Predicate<XdmItem>`	`eq(String value)` Obtain a predicate that tests whether the result of applying the XPath string() function to an item is equal to a given string
`static Predicate<XdmAtomicValue>`	`eq(XdmAtomicValue value)` Obtain a predicate that tests whether an atomic value compares equal to a supplied atomic value of a comparable type
`static <T extends XdmItem> Predicate<XdmItem>`	`every(Step<T> step, Predicate<? super XdmItem> condition)` Obtain a predicate that tests whether every item in the result of applying a step satisfies the supplied condition.
`static <T extends XdmItem> Predicate<XdmItem>`	`exists(Step<T> step)` Obtain a predicate that tests whether a supplied Step delivers a non-empty result
`static Predicate<XdmNode>`	`hasAttribute(String local)` Obtain a predicate that tests whether an item is an element node with a given attribute (whose name is in no namespace)
`static Predicate<XdmNode>`	`hasLocalName(String localName)` Obtain a predicate that tests whether an item is a node with a given local name, irrespective of the namespace
`static Predicate<? super XdmNode>`	`hasName(String uri, String localName)` Obtain a predicate that tests whether an item is a node with a given namespace URI and local name
`static Predicate<XdmNode>`	`hasNamespace(String uri)` Obtain a predicate that tests whether an item is a node with a given namespace URI
`static Predicate<XdmItem>`	`hasType(ItemType type)` Obtain a predicate that tests whether an item matches a given item type
`static Predicate<XdmItem>`	`isArray()` A predicate to test whether an item is an XDM array
`static Predicate<XdmItem>`	`isAtomic()` A predicate to test whether an item is an atomic value
`static Predicate<XdmItem>`	`isAttribute()` A predicate to test whether an item is an attribute node
`static Predicate<XdmItem>`	`isComment()` A predicate to test whether an item is a comment node
`static Predicate<XdmItem>`	`isDocument()` A predicate to test whether an item is a document node
`static Predicate<XdmItem>`	`isElement()` A predicate to test whether an item is an element node
`static Predicate<XdmItem>`	`isFunction()` A predicate to test whether an item is a function value (this includes maps and arrays)
`static Predicate<XdmItem>`	`isMap()` A predicate to test whether an item is an XDM map
`static Predicate<XdmItem>`	`isNamespace()` A predicate to test whether an item is a namespace node
`static Predicate<XdmItem>`	`isNode()` A predicate to test whether an item is a node
`static Predicate<XdmItem>`	`isProcessingInstruction()` A predicate to test whether an item is a processing instruction node
`static Predicate<XdmItem>`	`isText()` A predicate to test whether an item is a text node
`static Predicate<XdmItem>`	`matchesRegex(String regex)` Obtain a predicate that tests whether the result of applying the XPath string() function to an item matches a given regular expression
`static <T> Predicate<T>`	`not(Predicate<T> condition)` Return a `Predicate` that is the negation of a supplied `Predicate`
`static <T extends XdmItem> Predicate<XdmItem>`	`some(Step<T> step, Predicate<? super T> condition)` Obtain a predicate that tests whether there is some item in the result of applying a step that satisfies the supplied condition.

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

- Constructor Detail
  - Predicates
```
public Predicates()
```
- Method Detail
  - isNode
```
public static Predicate<XdmItem> isNode()
```
    A predicate to test whether an item is a node
    
    Returns:
    
    a predicate that returns true if given an item that is a node
  - isElement
```
public static Predicate<XdmItem> isElement()
```
    A predicate to test whether an item is an element node
    
    Returns:
    
    a predicate that returns true if given an item that is an element node
  - isAttribute
```
public static Predicate<XdmItem> isAttribute()
```
    A predicate to test whether an item is an attribute node
    
    Returns:
    
    a predicate that returns true if given an item that is an attribute node
  - isText
```
public static Predicate<XdmItem> isText()
```
    A predicate to test whether an item is a text node
    
    Returns:
    
    a predicate that returns true if given an item that is a text node
  - isComment
```
public static Predicate<XdmItem> isComment()
```
    A predicate to test whether an item is a comment node
    
    Returns:
    
    a predicate that returns true if given an item that is a comment node
  - isProcessingInstruction
```
public static Predicate<XdmItem> isProcessingInstruction()
```
    A predicate to test whether an item is a processing instruction node
    
    Returns:
    
    a predicate that returns true if given an item that is a processing instruction node
  - isDocument
```
public static Predicate<XdmItem> isDocument()
```
    A predicate to test whether an item is a document node
    
    Returns:
    
    a predicate that returns true if given an item that is a document node
  - isNamespace
```
public static Predicate<XdmItem> isNamespace()
```
    A predicate to test whether an item is a namespace node
    
    Returns:
    
    a predicate that returns true if given an item that is a namespace node
  - isAtomic
```
public static Predicate<XdmItem> isAtomic()
```
    A predicate to test whether an item is an atomic value
    Note: to test for a specific type of atomic value, use a predicate such as hasType(ItemType.XS_INTEGER)
    
    Returns:
    
    a predicate that returns true if given an item that is an atomic value.
  - isFunction
```
public static Predicate<XdmItem> isFunction()
```
    A predicate to test whether an item is a function value (this includes maps and arrays)
    
    Returns:
    
    a predicate that returns true if given an item that is a function, including maps and arrays
  - isMap
```
public static Predicate<XdmItem> isMap()
```
    A predicate to test whether an item is an XDM map
    
    Returns:
    
    a predicate that returns true if given an item that is a map
  - isArray
```
public static Predicate<XdmItem> isArray()
```
    A predicate to test whether an item is an XDM array
    
    Returns:
    
    a predicate that returns true if given an item that is an array
  - empty
```
public static <T extends XdmItem> Predicate<XdmItem> empty(Step<T> step)
```
    Obtain a predicate that tests whether a supplied Step delivers an empty result
    
    Parameters:
    
    step - a step to be applied to the item being tested
    
    Returns:
    
    a predicate that returns true if the supplied step returns an empty result. For example empty(attribute("id") is a predicate that returns true for a node that has no "id" attribute. Similarly CHILD.where(empty(child(IS_ELEMENT))) is a step that selects child elements having no element children.
  - not
```
public static <T> Predicate<T> not(Predicate<T> condition)
```
    Return a Predicate that is the negation of a supplied Predicate
    
    Type Parameters:
    
    T - The type of object to which the predicate is applicable
    
    Parameters:
    
    condition - the supplied predicate
    
    Returns:
    
    a Predicate that matches an item if and only if the supplied Predicate does not match the item.
  - exists
```
public static <T extends XdmItem> Predicate<XdmItem> exists(Step<T> step)
```
    Obtain a predicate that tests whether a supplied Step delivers a non-empty result
    
    Parameters:
    
    step - a step to be applied to the item being tested
    
    Returns:
    
    a predicate that returns true if the step returns a non-empty result. For example exists(attribute("id") is a predicate that returns true for a node that has an "id" attribute. So CHILD.where(exists(attribute("id")) is a step that selects child elements having an "id" attribute.
  - hasName
```
public static Predicate<? super XdmNode> hasName(String uri,
                                                 String localName)
```
    Obtain a predicate that tests whether an item is a node with a given namespace URI and local name
    
    Parameters:
    
    uri - the required namespace URI: supply a zero-length string to indicate the null namespace
    
    localName - the required local name
    
    Returns:
    
    a predicate that returns true if and only if the supplied item is a node with the given namespace URI and local name
  - hasLocalName
```
public static Predicate<XdmNode> hasLocalName(String localName)
```
    Obtain a predicate that tests whether an item is a node with a given local name, irrespective of the namespace
    
    Parameters:
    
    localName - the required local name. If a zero-length string is supplied, the predicate will match nodes having no name (for example, comments and text nodes)
    
    Returns:
    
    a predicate that returns true if and only if the supplied item is a node with the given local name, irrespective of the namespace
  - hasNamespace
```
public static Predicate<XdmNode> hasNamespace(String uri)
```
    Obtain a predicate that tests whether an item is a node with a given namespace URI
    
    Parameters:
    
    uri - the required namespace URI: supply a zero-length string to identify the null namespace
    
    Returns:
    
    a predicate that returns true if and only if the supplied item is a node with the given namespace URI. If a zero-length string is supplied, the predicate will also match nodes having no name, such as text and comment nodes, and nodes having a local name only, such as namespace and processing-instruction nodes.
  - hasAttribute
```
public static Predicate<XdmNode> hasAttribute(String local)
```
    Obtain a predicate that tests whether an item is an element node with a given attribute (whose name is in no namespace)
    
    Parameters:
    
    local - the required attribute name
    
    Returns:
    
    a predicate that returns true if and only if the supplied item is an element having an attribute with the given local name, in no namespace
  - attributeEq
```
public static Predicate<XdmNode> attributeEq(String local,
                                             String value)
```
    Obtain a predicate that tests whether an item is an element node with a given attribute (whose name is in no namespace) whose string value is equal to a given value
    
    Parameters:
    
    local - the required attribute name
    
    value - the required attribute value
    
    Returns:
    
    a predicate that returns true if and only if the supplied item is an element having an attribute with the given local name, in no namespace, whose string value is equal to the given value
  - hasType
```
public static Predicate<XdmItem> hasType(ItemType type)
```
    Obtain a predicate that tests whether an item matches a given item type
    
    Parameters:
    
    type - the required item type
    
    Returns:
    
    a predicate that returns true if and only if the supplied item matches the supplied item type. For example, hasType(ItemType.DATE_TIME) matches atomic values of type xs:dateTime.
  - some
```
public static <T extends XdmItem> Predicate<XdmItem> some(Step<T> step,
                                                          Predicate<? super T> condition)
```
    Obtain a predicate that tests whether there is some item in the result of applying a step that satisfies the supplied condition.
    For example, some(CHILD, exists(attribute("foo")) matches an element if it has a child element with an attribute whose local name is "foo".
    
    If the step returns an empty sequence the result will always be false.
    
    Parameters:
    
    step - the step to be evaluated
    
    condition - the predicate to be applied to the items returned by the step
  - every
```
public static <T extends XdmItem> Predicate<XdmItem> every(Step<T> step,
                                                           Predicate<? super XdmItem> condition)
```
    Obtain a predicate that tests whether every item in the result of applying a step satisfies the supplied condition.
    For example, every(CHILD, exists(attribute("foo")) matches an element if each of its child elements has an attribute whose local name is "foo".
    
    If the step returns an empty sequence the result will always be true.
    
    Parameters:
    
    step - the step to be evaluated
    
    condition - the predicate to be applied to the items returned by the step
  - eq
```
public static Predicate<XdmAtomicValue> eq(XdmAtomicValue value)
```
    Obtain a predicate that tests whether an atomic value compares equal to a supplied atomic value of a comparable type
    
    Parameters:
    
    value - the atomic value to be compared with
    
    Returns:
    
    a Predicate which returns true when applied to a value that is equal to the supplied value under the "is-same-key" comparison rules. (These are the rules used to compare key values in an XDM map. The rules are chosen to be context-free, error-free, and transitive.)
  - eq
```
public static Predicate<XdmItem> eq(String value)
```
    Obtain a predicate that tests whether the result of applying the XPath string() function to an item is equal to a given string
    
    Parameters:
    
    value - the string being tested
    
    Returns:
    
    a Predicate which returns true if the string value of the item being tested is equal to the given string under Java comparison rules for comparing strings.
  - matchesRegex
```
public static Predicate<XdmItem> matchesRegex(String regex)
```
    Obtain a predicate that tests whether the result of applying the XPath string() function to an item matches a given regular expression
    
    Parameters:
    
    regex - the regular expression (this is a Java regular expression, not an XPath regular expression)
    
    Returns:
    
    a Predicate which returns true if the string value of the item being tested contains a substring that matches the given regular expression. To test the string in its entirety, use anchors "^" and "$" in the regular expression.
  - eq
```
public static <T extends XdmItem> Predicate<XdmItem> eq(Step<T> step,
                                                        String value)
```
    Obtain a predicate that tests whether there is some item in the result of applying a step, whose string value is equal to a given string.
    For example, eq(attribute("id"), "foo") matches an element if it has an "id" attribute whose value is "foo".
    
    Parameters:
    
    step - the step to be evaluated
    
    value - the string to be compared against the items returned by the step
    
    Returns:
    
    a Predicate which returns true if some item selected by the step has as string value equal to the given string

Class Predicates

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Predicates

Method Detail

isNode

isElement

isAttribute

isText

isComment

isProcessingInstruction

isDocument

isNamespace

isAtomic

isFunction

isMap

isArray

empty

not

exists

hasName

hasLocalName

hasNamespace

hasAttribute

attributeEq

hasType

some

every

eq

eq

matchesRegex

eq