org.apache.derby.impl.sql.compile
Class DefaultNode

java.lang.Object
  extended by org.apache.derby.impl.sql.compile.QueryTreeNode
      extended by org.apache.derby.impl.sql.compile.ValueNode
          extended by org.apache.derby.impl.sql.compile.DefaultNode
All Implemented Interfaces:
Visitable

public class DefaultNode
extends ValueNode

DefaultNode represents a column/parameter default.


Field Summary
private  java.lang.String columnName
           
private  java.lang.String defaultText
           
private  ValueNode defaultTree
           
 
Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode
transformed
 
Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, isPrivilegeCollectionRequired
 
Constructor Summary
DefaultNode()
           
 
Method Summary
 ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector)
          Bind this expression.
 void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb)
          Generate code for this calculation.
 java.lang.String getDefaultText()
          Get the text of the default.
(package private)  ValueNode getDefaultTree()
          Get the query tree for the default.
 void init(java.lang.Object columnName)
          Initializer for insert/update
 void init(java.lang.Object defaultTree, java.lang.Object defaultText)
          Initializer for a column/parameter default.
protected  boolean isEquivalent(ValueNode other)
          Tests if this node is equivalent to the specified ValueNode.
static ValueNode parseDefault(java.lang.String defaultText, LanguageConnectionContext lcc, CompilerContext cc)
          Parse a default and turn it into a query tree.
 void printSubNodes(int depth)
          Prints the sub-nodes of this object.
 java.lang.String toString()
          Convert this object to a String.
 
Methods inherited from class org.apache.derby.impl.sql.compile.ValueNode
bindExpression, categorize, changeToCNF, checkIsBoolean, checkTopPredicatesForEqualsConditions, constantExpression, copyFields, eliminateNots, evaluateConstantExpressions, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getOrderableVariantType, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, init, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isConstantExpression, isInListProbeNode, isParameterNode, isRelationalOperator, isSameNodeType, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, requiresTypeFromContext, selectivity, setCollationInfo, setCollationInfo, setCollationUsingCompilationSchema, setCollationUsingCompilationSchema, setNullability, setTransformed, setType, setType, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop
 
Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, acceptChildren, bindOffsetFetch, bindRowMultiSet, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, foundString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, stackPrint, treePrint, treePrint, verifyClassExist
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

columnName

private java.lang.String columnName

defaultText

private java.lang.String defaultText

defaultTree

private ValueNode defaultTree
Constructor Detail

DefaultNode

public DefaultNode()
Method Detail

init

public void init(java.lang.Object defaultTree,
                 java.lang.Object defaultText)
Initializer for a column/parameter default.

Overrides:
init in class QueryTreeNode
Parameters:
defaultTree - Query tree for default
defaultText - The text of the default.

init

public void init(java.lang.Object columnName)
Initializer for insert/update

Overrides:
init in class QueryTreeNode

getDefaultText

public java.lang.String getDefaultText()
Get the text of the default.


getDefaultTree

ValueNode getDefaultTree()
Get the query tree for the default.

Returns:
The query tree for the default.

toString

public java.lang.String toString()
Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.

Overrides:
toString in class ValueNode
Returns:
This object as a String

printSubNodes

public void printSubNodes(int depth)
Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Overrides:
printSubNodes in class QueryTreeNode
Parameters:
depth - The depth of this node in the tree

bindExpression

public ValueNode bindExpression(FromList fromList,
                                SubqueryList subqueryList,
                                java.util.Vector aggregateVector)
                         throws StandardException
Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. In this case, there are no sub-expressions, and the return type is already known, so this is just a stub.

Overrides:
bindExpression in class ValueNode
Parameters:
fromList - The FROM list for the query this expression is in, for binding columns.
subqueryList - The subquery list being built as we find SubqueryNodes
aggregateVector - The aggregate vector being built as we find AggregateNodes
Returns:
The new top of the expression tree.
Throws:
StandardException - Thrown on failure

parseDefault

public static ValueNode parseDefault(java.lang.String defaultText,
                                     LanguageConnectionContext lcc,
                                     CompilerContext cc)
                              throws StandardException
Parse a default and turn it into a query tree.

Parameters:
defaultText - Text of Default.
lcc - LanguageConnectionContext
cc - CompilerContext
Returns:
The parsed default as a query tree.
Throws:
StandardException - Thrown on failure

generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               MethodBuilder mb)
                        throws StandardException
Description copied from class: ValueNode
Generate code for this calculation. This is a place-holder method - it should not be called.

Overrides:
generateExpression in class ValueNode
Parameters:
acb - The ExpressionClassBuilder for the class being built
mb - The method the expression will go into
Throws:
StandardException - Thrown on failure

isEquivalent

protected boolean isEquivalent(ValueNode other)
Description copied from class: ValueNode
Tests if this node is equivalent to the specified ValueNode. Two ValueNodes are considered equivalent if they will evaluate to the same value during query execution.

This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase.

Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown.

One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.:

SELECT c1+c2 FROM t1 GROUP BY c1+c2

In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below:

Specified by:
isEquivalent in class ValueNode
Parameters:
other - the node to compare this ValueNode against.
Returns:
true if the two nodes are equivalent, false otherwise.

Built on Thu 2012-03-29 21:53:33+0000, from revision ???

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