CompiledExpression

java.lang.Object
- net.sf.saxon.expr.Expression
- - com.saxonica.ee.bytecode.CompiledExpression

All Implemented Interfaces:

ExportAgent, Locatable, IdentityComparable
```
public class CompiledExpression
extends Expression
```
An expression that has been compiled to Java bytecode. The actual bytecode is contained in a separate object of type GeneratedCode, to which evaluation is delegated

Field Summary
- Fields inherited from class net.sf.saxon.expr.Expression
  EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors
Constructor and Description

CompiledExpression(Expression original, GeneratedCode byteCode)

Constructors
Constructor and Description
`CompiledExpression(Expression original, GeneratedCode byteCode)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`PathMap.PathMapNodeSet`	`addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)` Add a representation of this expression to a PathMap.
`void`	`checkForUpdatingSubexpressions()` Check to ensure that this expression does not contain any inappropriate updating subexpressions.
`void`	`checkPermittedContents(SchemaType parentType, boolean whole)` Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type.
`protected int`	`computeCardinality()` Compute the static cardinality of this expression
`int`	`computeDependencies()` Compute the dependencies of an expression, as the union of the dependencies of its subexpressions.
`int`	`computeHashCode()` Hashcode supporting equals()
`protected int`	`computeSpecialProperties()` Compute the special properties of this expression.
`Expression`	`copy(RebindingMap rebindings)` Copy an expression.
`boolean`	`effectiveBooleanValue(XPathContext context)` Get the effective boolean value of the expression.
`boolean`	`equals(java.lang.Object other)` Is this expression the same as another expression?
`Item`	`evaluateItem(XPathContext context)` Evaluate an expression as a single item.
`void`	`evaluatePendingUpdates(XPathContext context, PendingUpdateList pul)` Evaluate an updating expression, adding the results to a Pending Update List.
`void`	`export(ExpressionPresenter out)` Diagnostic print of expression structure.
`int`	`getCardinality()` Determine the static cardinality of the expression.
`java.lang.String`	`getClassName()`
`int`	`getConstructType()` Get the type of this expression for use in tracing and diagnostics
`int`	`getDependencies()` Determine which aspects of the context the expression depends on.
`java.lang.String`	`getExpressionName()` Get a name identifying the kind of expression, in terms meaningful to a user.
`GeneratedCode`	`getGeneratedCode()`
`int`	`getImplementationMethod()` An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
`Expression`	`getInterpretedExpression()` Get the original (uncompiled) expression of which this is the compiled form
`int`	`getIntrinsicDependencies()` Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
`ItemType`	`getItemType()` Determine the static item type of the expression, as precisely possible.
`StructuredQName`	`getObjectName()`
`java.util.Iterator<java.lang.String>`	`getProperties()` Get an iterator over all the properties available.
`java.lang.Object`	`getProperty(java.lang.String name)`
`boolean`	`isSubtreeExpression()` Determine whether the expression can be evaluated without reference to the part of the context document outside the subtree rooted at the context node.
`boolean`	`isUpdatingExpression()` Determine whether this is an updating expression as defined in the XQuery update specification
`boolean`	`isVacuousExpression()` Determine whether this is a vacuous expression as defined in the XQuery update specification
`SequenceIterator<?>`	`iterate(XPathContext context)` Return an Iterator to iterate over the values of a sequence.
`void`	`process(XPathContext context)` Process the instruction, without returning any tail calls
`void`	`setClassName(java.lang.String cname)`
`java.lang.String`	`toString()` The toString() method for an expression attempts to give a representation of the expression in an XPath-like form.

Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, computeStaticProperties, dynamicError, evaluateAsString, explain, getConfiguration, getCost, getEvaluationMethod, getExtraProperty, getIntegerBounds, getLocalRetainedStaticContext, getLocation, getNetCost, getPackageData, getParentExpression, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getStreamerName, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isLiftable, isMultiThreaded, isStaticPropertiesKnown, markTailFunctionCalls, operandList, operands, operandSparseList, optimize, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, typeCheck, typeCheckChildren, typeError, unordered, verifyParentPointers

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

- Constructor Detail
  - CompiledExpression
```
public CompiledExpression(Expression original,
                          GeneratedCode byteCode)
```
- Method Detail
  - getInterpretedExpression
```
public Expression getInterpretedExpression()
```
    Get the original (uncompiled) expression of which this is the compiled form
    
    Overrides:
    
    getInterpretedExpression in class Expression
    
    Returns:
    
    the original expression
  - getGeneratedCode
```
public GeneratedCode getGeneratedCode()
```
  - setClassName
```
public void setClassName(java.lang.String cname)
```
  - getClassName
```
public java.lang.String getClassName()
```
  - getExpressionName
```
public java.lang.String getExpressionName()
```
    Description copied from class: Expression
    
    Get a name identifying the kind of expression, in terms meaningful to a user.
    
    Overrides:
    
    getExpressionName in class Expression
    
    Returns:
    
    a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in export() output displaying the expression.
  - getImplementationMethod
```
public int getImplementationMethod()
```
    Description copied from class: Expression
    
    An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.
    
    Specified by:
    
    getImplementationMethod in class Expression
    
    Returns:
    
    the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD
  - getCardinality
```
public int getCardinality()
```
    Description copied from class: Expression
    
    Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
    
    Overrides:
    
    getCardinality in class Expression
    
    Returns:
    
    one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).
  - getItemType
```
public ItemType getItemType()
```
    Description copied from class: Expression
    
    Determine the static item type of the expression, as precisely possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.
    This method should always return a result, though it may be the best approximation that is available at the time.
    
    Specified by:
    
    getItemType in class Expression
    
    Returns:
    
    a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)
  - getDependencies
```
public int getDependencies()
```
    Description copied from class: Expression
    
    Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE. The default implementation combines the intrinsic dependencies of this expression with the dependencies of the subexpressions, computed recursively. This is overridden for expressions such as FilterExpression where a subexpression's dependencies are not necessarily inherited by the parent expression.
    
    Overrides:
    
    getDependencies in class Expression
    
    Returns:
    
    a set of bit-significant flags identifying the dependencies of the expression
  - process
```
public void process(XPathContext context)
             throws XPathException
```
    Description copied from class: Expression
    
    Process the instruction, without returning any tail calls
    
    Overrides:
    
    process in class Expression
    
    Parameters:
    
    context - The dynamic context, giving access to the current node, the current variables, etc.
    
    Throws:
    
    XPathException - if a dynamic error occurs
  - evaluatePendingUpdates
```
public void evaluatePendingUpdates(XPathContext context,
                                   PendingUpdateList pul)
                            throws XPathException
```
    Description copied from class: Expression
    
    Evaluate an updating expression, adding the results to a Pending Update List. The default implementation of this method, which is used for non-updating expressions, throws an UnsupportedOperationException
    
    Overrides:
    
    evaluatePendingUpdates in class Expression
    
    Parameters:
    
    context - the XPath dynamic evaluation context
    
    pul - the pending update list to which the results should be written
    
    Throws:
    
    XPathException - if evaluation fails
  - toString
```
public java.lang.String toString()
```
    Description copied from class: Expression
    
    The toString() method for an expression attempts to give a representation of the expression in an XPath-like form.
    
    For subclasses of Expression that represent XPath expressions, the result should always be a string that parses as an XPath 3.0 expression. The expression produced should be equivalent to the original making certain assumptions about the static context. In general the expansion will make no assumptions about namespace bindings, except that (a) the prefix "xs" is used to refer to the XML Schema namespace, and (b) the default function namespace is assumed to be the "fn" namespace.
    
    In the case of XSLT instructions and XQuery expressions, the toString() method gives an abstracted view of the syntax that is not designed in general to be parseable.
    
    Overrides:
    
    toString in class Expression
    
    Returns:
    
    a representation of the expression as a string
  - export
```
public void export(ExpressionPresenter out)
            throws XPathException
```
    Description copied from class: Expression
    
    Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
    
    Specified by:
    
    export in interface ExportAgent
    
    Specified by:
    
    export in class Expression
    
    Parameters:
    
    out - the expression presenter used to display the structure
    
    Throws:
    
    XPathException - if the export fails, for example if an expression is found that won't work in the target environment.
  - checkPermittedContents
```
public void checkPermittedContents(SchemaType parentType,
                                   boolean whole)
                            throws XPathException
```
    Description copied from class: Expression
    
    Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type. It's always OK to say yes, since the check will be repeated at run-time. The process of checking element and attribute constructors against the content model of a complex type also registers the type of content expected of those constructors, so the static validation can continue recursively.
    
    Overrides:
    
    checkPermittedContents in class Expression
    
    Parameters:
    
    parentType - the "given complex type": the method is checking that the nodes returned by this expression are acceptable members of the content model of this type
    
    whole - if true, we want to check that the value of this expression satisfies the content model as a whole; if false we want to check that the value of the expression is acceptable as one part of the content
    
    Throws:
    
    XPathException - if the value delivered by this expression cannot be part of the content model of the given type
  - computeCardinality
```
protected int computeCardinality()
```
    Description copied from class: Expression
    
    Compute the static cardinality of this expression
    
    Specified by:
    
    computeCardinality in class Expression
    
    Returns:
    
    the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE. May also return StaticProperty.ALLOWS_ZERO if the result is known to be an empty sequence, or StaticProperty.ALLOWS_MANY if if is known to return a sequence of length two or more.
  - computeSpecialProperties
```
protected int computeSpecialProperties()
```
    Description copied from class: Expression
    
    Compute the special properties of this expression. These properties are denoted by a bit-significant integer, possible values are in class StaticProperty. The "special" properties are properties other than cardinality and dependencies, and most of them relate to properties of node sequences, for example whether the nodes are in document order.
    
    Overrides:
    
    computeSpecialProperties in class Expression
    
    Returns:
    
    the special properties, as a bit-significant integer
  - computeDependencies
```
public int computeDependencies()
```
    Description copied from class: Expression
    
    Compute the dependencies of an expression, as the union of the dependencies of its subexpressions. (This is overridden for path expressions and filter expressions, where the dependencies of a subexpression are not all propogated). This method should be called only once, to compute the dependencies; after that, getDependencies should be used.
    
    Overrides:
    
    computeDependencies in class Expression
    
    Returns:
    
    the depencies, as a bit-mask
  - getIntrinsicDependencies
```
public int getIntrinsicDependencies()
```
    Description copied from class: Expression
    
    Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".
    
    Overrides:
    
    getIntrinsicDependencies in class Expression
    
    Returns:
    
    a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
  - checkForUpdatingSubexpressions
```
public void checkForUpdatingSubexpressions()
                                    throws XPathException
```
    Description copied from class: Expression
    
    Check to ensure that this expression does not contain any inappropriate updating subexpressions. This check is overridden for those expressions that permit updating subexpressions.
    
    Overrides:
    
    checkForUpdatingSubexpressions in class Expression
    
    Throws:
    
    XPathException - if the expression has a non-permitted updating subexpression
  - isUpdatingExpression
```
public boolean isUpdatingExpression()
```
    Description copied from class: Expression
    
    Determine whether this is an updating expression as defined in the XQuery update specification
    
    Overrides:
    
    isUpdatingExpression in class Expression
    
    Returns:
    
    true if this is an updating expression
  - isVacuousExpression
```
public boolean isVacuousExpression()
```
    Description copied from class: Expression
    
    Determine whether this is a vacuous expression as defined in the XQuery update specification
    
    Overrides:
    
    isVacuousExpression in class Expression
    
    Returns:
    
    true if this expression is vacuous
  - copy
```
public Expression copy(RebindingMap rebindings)
```
    Description copied from class: Expression
    
    Copy an expression. This makes a deep copy.
    
    Specified by:
    
    copy in class Expression
    
    Parameters:
    
    rebindings - a mutable list of (old binding, new binding) pairs that is used to update the bindings held in any local variable references that are copied.
    
    Returns:
    
    the copy of the original expression
  - getConstructType
```
public int getConstructType()
```
    Description copied from class: Expression
    
    Get the type of this expression for use in tracing and diagnostics
    
    Overrides:
    
    getConstructType in class Expression
    
    Returns:
    
    the type of expression, as enumerated in class LocationKind
  - getObjectName
```
public StructuredQName getObjectName()
```
    Overrides:
    
    getObjectName in class Expression
  - equals
```
public boolean equals(java.lang.Object other)
```
    Is this expression the same as another expression?
    
    Overrides:
    
    equals in class Expression
    
    Parameters:
    
    other - the expression to be compared with this one
    
    Returns:
    
    true if the two expressions are statically equivalent
  - computeHashCode
```
public int computeHashCode()
```
    Hashcode supporting equals()
    
    Overrides:
    
    computeHashCode in class Expression
    
    Returns:
    
    a computed hash code
  - getProperty
```
public java.lang.Object getProperty(java.lang.String name)
```
    Overrides:
    
    getProperty in class Expression
  - getProperties
```
public java.util.Iterator<java.lang.String> getProperties()
```
    Description copied from class: Expression
    
    Get an iterator over all the properties available. The values returned by the iterator will be of type String, and each string can be supplied as input to the getProperty() method to retrieve the value of the property. The iterator may return properties whose value is null.
    
    Overrides:
    
    getProperties in class Expression
    
    Returns:
    
    an iterator over the properties
  - addToPathMap
```
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
```
    Description copied from class: Expression
    
    Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.
    The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
    
    Overrides:
    
    addToPathMap in class Expression
    
    Parameters:
    
    pathMap - the PathMap to which the expression should be added
    
    pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
    
    Returns:
    
    the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.
  - isSubtreeExpression
```
public boolean isSubtreeExpression()
```
    Description copied from class: Expression
    
    Determine whether the expression can be evaluated without reference to the part of the context document outside the subtree rooted at the context node.
    
    Overrides:
    
    isSubtreeExpression in class Expression
    
    Returns:
    
    true if the expression has no dependencies on the context node, or if the only dependencies on the context node are downward selections using the self, child, descendant, attribute, and namespace axes.
  - iterate
```
public SequenceIterator<?> iterate(XPathContext context)
                            throws XPathException
```
    Description copied from class: Expression
    
    Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.
    
    Overrides:
    
    iterate in class Expression
    
    Parameters:
    
    context - supplies the context for evaluation
    
    Returns:
    
    a SequenceIterator that can be used to iterate over the result of the expression
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression
  - evaluateItem
```
public Item evaluateItem(XPathContext context)
                  throws XPathException
```
    Description copied from class: Expression
    
    Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.
    
    Overrides:
    
    evaluateItem in class Expression
    
    Parameters:
    
    context - The context in which the expression is to be evaluated
    
    Returns:
    
    the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression
  - effectiveBooleanValue
```
public boolean effectiveBooleanValue(XPathContext context)
                              throws XPathException
```
    Description copied from class: Expression
    
    Get the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.
    
    Overrides:
    
    effectiveBooleanValue in class Expression
    
    Parameters:
    
    context - The context in which the expression is to be evaluated
    
    Returns:
    
    the effective boolean value
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression

Class CompiledExpression

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

Constructor Summary

Method Summary

Methods inherited from class net.sf.saxon.expr.Expression

Methods inherited from class java.lang.Object

Constructor Detail

CompiledExpression

Method Detail

getInterpretedExpression

getGeneratedCode

setClassName

getClassName

getExpressionName

getImplementationMethod

getCardinality

getItemType

getDependencies

process

evaluatePendingUpdates

toString

export

checkPermittedContents

computeCardinality

computeSpecialProperties

computeDependencies

getIntrinsicDependencies

checkForUpdatingSubexpressions

isUpdatingExpression

isVacuousExpression

copy

getConstructType

getObjectName

equals

computeHashCode

getProperty

getProperties

addToPathMap

isSubtreeExpression

iterate

evaluateItem

effectiveBooleanValue