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package oracle.toplink.essentials.internal.parsing;
import java.util.*;
// TopLink imports
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.mappings.DatabaseMapping;
import oracle.toplink.essentials.queryframework.ObjectLevelReadQuery;
import oracle.toplink.essentials.queryframework.ReportQuery;
/**
* INTERNAL
* <p><b>Purpose</b>: The Superclass for for typed variables, local variables and remote variables
* <p><b>Responsibilities</b>:<ul>
* <li> Generate the correct expression for an AND in EJBQL
* </ul>
* @author Jon Driscoll and Joel Lucuik
* @since TopLink 4.0
*/
public class VariableNode extends Node {
/** */
private String variableName;
/** */
private String canonicalName;
/**
* VariableNode constructor comment.
*/
public VariableNode() {
super();
}
public VariableNode(String newVariableName) {
setVariableName(newVariableName);
}
public String getVariableName() {
return variableName;
}
public void setVariableName(String newVariableName) {
variableName = newVariableName;
canonicalName = IdentificationVariableDeclNode.calculateCanonicalName(newVariableName);
}
/** */
public String getCanonicalVariableName() {
return canonicalName;
}
/**
* INTERNAL
* Is this node a VariableNode
*/
public boolean isVariableNode() {
return true;
}
/**
* INTERNAL
* Apply this node to the passed query
*/
public void applyToQuery(ObjectLevelReadQuery theQuery, GenerationContext generationContext) {
String name = getCanonicalVariableName();
ParseTreeContext context = generationContext.getParseTreeContext();
if (theQuery instanceof ReportQuery) {
ReportQuery reportQuery = (ReportQuery)theQuery;
Expression expression = generationContext.expressionFor(name);
if (expression == null) {
expression = generateExpression(generationContext);
}
addAttributeWithFetchJoins(reportQuery, expression, generationContext);
} else {
addFetchJoins(theQuery, generationContext);
}
}
/**
* INTERNAL
* Add the variable as ReportQuery item. The method checks for any JOIN
* FETCH nodes of the current variable and adds them as part of the
* ReportQuery item.
*/
private void addAttributeWithFetchJoins(ReportQuery reportQuery,
Expression expression,
GenerationContext context) {
String name = getCanonicalVariableName();
List fetchJoinNodes = context.getParseTreeContext().getFetchJoins(name);
if (fetchJoinNodes == null) {
reportQuery.addAttribute(name, expression);
} else {
List fetchJoinExprs = new ArrayList(fetchJoinNodes.size());
for (Iterator i = fetchJoinNodes.iterator(); i.hasNext(); ) {
Node node = (Node)i.next();
fetchJoinExprs.add(node.generateExpression(context));
}
reportQuery.addItem(name, expression, fetchJoinExprs);
}
}
/**
* INTERNAL
* Check for any JOIN FETCH nodes of the current variable and add them as
* joined attributes. This method is called in case of a non ReportQuery
* instance.
*/
private void addFetchJoins(ObjectLevelReadQuery theQuery,
GenerationContext context) {
String name = getCanonicalVariableName();
List fetchJoinNodes = context.getParseTreeContext().getFetchJoins(name);
if (fetchJoinNodes != null) {
for (Iterator i = fetchJoinNodes.iterator(); i.hasNext(); ) {
Node node = (Node)i.next();
theQuery.addJoinedAttribute(node.generateExpression(context));
}
}
}
/**
* INTERNAL
* This node represent an unqualified field access in the case the method
* is called and the variableName is not defined as identification variable.
* The method returns a DotNode representing a qualified field access with
* the base variable as left child node. The right child node is an
* AttributeNode using the variableName as field name.
*/
public Node qualifyAttributeAccess(ParseTreeContext context) {
return context.isVariable(variableName) ? this :
(Node)context.getNodeFactory().newQualifiedAttribute(
getLine(), getColumn(), context.getBaseVariable(), variableName);
}
/**
* INTERNAL
* Validate node and calculate its type.
*/
public void validate(ParseTreeContext context) {
TypeHelper typeHelper = context.getTypeHelper();
String name = getCanonicalVariableName();
if (context.isRangeVariable(name)) {
String schema = context.schemaForVariable(name);
setType(typeHelper.resolveSchema(schema));
} else {
Node path = context.pathForVariable(name);
if (path == null) {
throw EJBQLException.aliasResolutionException(
context.getQueryInfo(), getLine(), getColumn(), name);
} else {
setType(path.getType());
}
}
context.usedVariable(name);
if (context.isDeclaredInOuterScope(name)) {
context.registerOuterScopeVariable(name);
}
}
public Expression generateBaseBuilderExpression(GenerationContext context) {
//create builder, and add it, and answer it
//BUG 3106877: Need to create builder using the actual class (if using parallel expressions)
if (context.useParallelExpressions()) {
return new ExpressionBuilder(this.resolveClass(context));
} else {
return new ExpressionBuilder();
}
}
public Expression generateExpression(GenerationContext generationContext) {
Expression myExpression = null;
String name = getCanonicalVariableName();
//is there a cached Expression?
myExpression = generationContext.expressionFor(name);
if (myExpression != null) {
return myExpression;
}
//Either I have an alias type, or I'm an IN declaration
if (generationContext.getParseTreeContext().isRangeVariable(name)) {
myExpression = generateBaseBuilderExpression(generationContext);
} else {
myExpression = generateExpressionForAlias(generationContext);
}
generationContext.addExpression(myExpression, name);
return myExpression;
}
public Expression generateExpressionForAlias(GenerationContext context) {
// BUG 3105651: Verify if we need to resolve this alias, or just use
// an empty ExpressionBuilder. See OrderByItemNode.generateExpression()
// for more details
if (context.getParseTree().getQueryNode().isSelectNode() && context.shouldCheckSelectNodeBeforeResolving() && (((SelectNode)context.getParseTree().getQueryNode()).isSelected(this.getCanonicalVariableName()))) {
return new ExpressionBuilder();
}
Node nodeForAlias = getNodeForAlias(context);
//assume that if there is no node available for the given variable, then
//there must be an alias mismatch. Assume they know their attribute names better
//than their alias names. - JGL
if (nodeForAlias == null) {
throw EJBQLException.aliasResolutionException(
context.getParseTreeContext().getQueryInfo(),
getLine(), getColumn(), getVariableName());
}
//create builder, and answer it
return nodeForAlias.generateExpression(context);
}
public Node getNodeForAlias(GenerationContext context) {
//Node node = context.getParseTreeContext().nodeForIdentifier(getCanonicalVariableName());
//return node != null ? ((IdentificationVariableDeclNode)node).getPath() : null;
return context.getParseTreeContext().pathForVariable(getCanonicalVariableName());
}
/**
* isAlias: Answer true if this variable represents an alias in the FROM clause.
* i.e. "FROM Employee emp" declares "emp" as an alias
*/
public boolean isAlias(GenerationContext context) {
return isAlias(context.getParseTreeContext());
}
public boolean isAlias(ParseTreeContext context) {
String classNameForAlias = context.schemaForVariable(getCanonicalVariableName());
return classNameForAlias != null;
}
/**
* resolveClass: Answer the class which corresponds to my variableName. This is the class for
* an alias, where the variableName is registered to an alias.
*/
public Class resolveClass(GenerationContext generationContext) {
Class clazz = null;
String name = getCanonicalVariableName();
ParseTreeContext context = generationContext.getParseTreeContext();
if (context.isRangeVariable(name)) {
String schema = context.schemaForVariable(name);
clazz = context.classForSchemaName(schema, generationContext);
} else {
DotNode path = (DotNode)context.pathForVariable(name);
if (path == null) {
throw EJBQLException.aliasResolutionException(
context.getQueryInfo(), getLine(), getColumn(), name);
} else {
clazz = path.resolveClass(generationContext);
}
}
return clazz;
}
public String toString(int indent) {
StringBuffer buffer = new StringBuffer();
toStringIndent(indent, buffer);
buffer.append(toStringDisplayName() + "[" + getVariableName() + "]");
return buffer.toString();
}
/**
* INTERNAL
* Get the string representation of this node.
*/
public String getAsString() {
return getVariableName();
}
}
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