Package com.yahoo.searchlib.expression

Class ExpressionNode

java.lang.Object

com.yahoo.vespa.objects.Selectable

com.yahoo.vespa.objects.Identifiable

com.yahoo.searchlib.expression.ExpressionNode

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

AggregationRefNode, AggregationResult, ConstantNode, DocumentAccessorNode, FunctionNode, RelevanceNode

public abstract class ExpressionNode
extends com.yahoo.vespa.objects.Identifiable
implements Serializable

This is the base class for all expression node types. There is no execution logic implemented in Java, since that all happens in the C++ backend. This class hierarchy is for building the expression tree to pass to the backend.

Author:

baldersheim, Simon Thoresen Hult

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static int	classId

Constructor Summary

Constructors

Constructor	Description
ExpressionNode()

Method Summary

Modifier and Type	Method	Description
ExpressionNode	clone()
boolean	equals(Object obj)
protected abstract boolean	equalsExpression(ExpressionNode obj)
boolean	execute()	Execute expression.
protected void	executeIterative(ResultNode arg, ResultNode result)	Give an argument to this expression and store the result.
abstract ResultNode	getResult()	Get the result of this expression.
protected void	onArgument(ResultNode arg, ResultNode result)
protected void	onDeserialize(com.yahoo.vespa.objects.Deserializer buf)
protected boolean	onExecute()
protected int	onGetClassId()
protected void	onPrepare()
protected void	onSerialize(com.yahoo.vespa.objects.Serializer buf)
void	prepare()	Prepare expression for execution.
void	visitMembers(com.yahoo.vespa.objects.ObjectVisitor visitor)

Methods inherited from class com.yahoo.vespa.objects.Identifiable

create, createFromId, deserialize, deserializeOptional, deserializeWithId, equals, getClassId, getRawUtf8Bytes, getUtf8, hashCode, putUtf8, registerClass, serialize, serializeOptional, serializeWithId, toString

Methods inherited from class com.yahoo.vespa.objects.Selectable

select, select, selectMembers

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

classId

public static final int classId

Constructor Detail

ExpressionNode

public ExpressionNode()

Method Detail

prepare

public void prepare()

Prepare expression for execution.

execute

public boolean execute()

Execute expression.

Returns:

true if successful, false if not.

executeIterative

protected void executeIterative(ResultNode arg,
                                ResultNode result)

Give an argument to this expression and store the result.

Parameters:

arg - Argument to use for expression.

result - Node to contain the result.

onExecute

protected boolean onExecute()

onPrepare

protected void onPrepare()

onArgument

protected void onArgument(ResultNode arg,
                          ResultNode result)

onGetClassId

protected int onGetClassId()

Overrides:

onGetClassId in class com.yahoo.vespa.objects.Identifiable

onSerialize

protected void onSerialize(com.yahoo.vespa.objects.Serializer buf)

Overrides:

onSerialize in class com.yahoo.vespa.objects.Identifiable

onDeserialize

protected void onDeserialize(com.yahoo.vespa.objects.Deserializer buf)

Overrides:

onDeserialize in class com.yahoo.vespa.objects.Identifiable

visitMembers

public void visitMembers(com.yahoo.vespa.objects.ObjectVisitor visitor)

Overrides:

visitMembers in class com.yahoo.vespa.objects.Identifiable

clone

public ExpressionNode clone()

Overrides:

clone in class com.yahoo.vespa.objects.Identifiable

equals

public final boolean equals(Object obj)

Overrides:

equals in class com.yahoo.vespa.objects.Identifiable

equalsExpression

protected abstract boolean equalsExpression(ExpressionNode obj)

getResult

public abstract ResultNode getResult()

Get the result of this expression.

Returns:

the result as a ResultNode.