/*
Derby - Class org.apache.derby.impl.sql.compile.JavaToSQLValueNode
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to you under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.derby.impl.sql.compile;
import org.apache.derby.iapi.sql.dictionary.DataDictionary;
import org.apache.derby.iapi.types.DataTypeDescriptor;
import org.apache.derby.iapi.types.TypeId;
import org.apache.derby.iapi.sql.compile.TypeCompiler;
import org.apache.derby.iapi.reference.SQLState;
import org.apache.derby.iapi.services.compiler.MethodBuilder;
import org.apache.derby.iapi.services.compiler.LocalField;
import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.impl.sql.compile.ExpressionClassBuilder;
import org.apache.derby.iapi.sql.compile.Visitable;
import org.apache.derby.iapi.sql.compile.Visitor;
import org.apache.derby.iapi.services.sanity.SanityManager;
import java.lang.reflect.Modifier;
import org.apache.derby.iapi.util.JBitSet;
import java.util.Vector;
/**
* This node type converts a value from the Java domain to the SQL domain.
*/
public class JavaToSQLValueNode extends ValueNode
{
JavaValueNode javaNode;
/**
* Initializer for a JavaToSQLValueNode
*
* @param value The Java value to convert to the SQL domain
*/
public void init(Object value)
{
this.javaNode = (JavaValueNode) value;
}
/**
* Preprocess an expression tree. We do a number of transformations
* here (including subqueries, IN lists, LIKE and BETWEEN) plus
* subquery flattening.
* NOTE: This is done before the outer ResultSetNode is preprocessed.
*
* @param numTables Number of tables in the DML Statement
* @param outerFromList FromList from outer query block
* @param outerSubqueryList SubqueryList from outer query block
* @param outerPredicateList PredicateList from outer query block
*
* @return The modified expression
*
* @exception StandardException Thrown on error
*/
public ValueNode preprocess(int numTables,
FromList outerFromList,
SubqueryList outerSubqueryList,
PredicateList outerPredicateList)
throws StandardException
{
javaNode.preprocess(numTables,
outerFromList, outerSubqueryList,
outerPredicateList);
return this;
}
/**
* Do code generation for this conversion of a value from the Java to
* the SQL domain.
*
* @param acb The ExpressionClassBuilder for the class we're generating
* @param mb the method the expression will go into
*
* @exception StandardException Thrown on error
*/
public void generateExpression(ExpressionClassBuilder acb,
MethodBuilder mb)
throws StandardException
{
TypeId resultType;
String resultTypeName;
/*
** Tell the Java node that it's value is being returned to the
** SQL domain. This way, it knows whether the checking for a null
** receiver is to be done at the Java level or the SQL level.
*/
javaNode.returnValueToSQLDomain();
/* Generate the receiver, if any. */
boolean hasReceiver = javaNode.generateReceiver(acb, mb);
/*
** If the java expression has a receiver, we want to check whether
** it's null before evaluating the whole expression (to avoid
** a NullPointerException.
*/
if (hasReceiver)
{
/*
** There is a receiver. Generate a null SQL value to return
** in case the receiver is null. First, create a field to hold
** the null SQL value.
*/
String nullValueClass = getTypeCompiler().interfaceName();
LocalField nullValueField =
acb.newFieldDeclaration(Modifier.PRIVATE, nullValueClass);
/*
** There is a receiver. Generate the following to test
** for null:
**
** (receiverExpression == null) ?
*/
mb.conditionalIfNull();
mb.getField(nullValueField);
acb.generateNullWithExpress(mb, getTypeCompiler(),
getTypeServices().getCollationType());
/*
** We have now generated the expression to test, and the
** "true" side of the ?: operator. Finish the "true" side
** so we can generate the "false" side.
*/
mb.startElseCode();
}
resultType = getTypeId();
TypeCompiler tc = getTypeCompiler();
resultTypeName = tc.interfaceName();
/* Allocate an object for re-use to hold the result of the conversion */
LocalField field = acb.newFieldDeclaration(Modifier.PRIVATE, resultTypeName);
/* Generate the expression for the Java value under us */
javaNode.generateExpression(acb, mb);
/* Generate the SQL value, which is always nullable */
acb.generateDataValue(mb, tc,
getTypeServices().getCollationType(), field);
/*
** If there was a receiver, the return value will be the result
** of the ?: operator.
*/
if (hasReceiver)
{
mb.completeConditional();
}
}
/**
* Prints the sub-nodes of this object. See QueryTreeNode for
* how tree printing is supposed to work.
*
* @param depth The depth of this node in the tree
*/
public void printSubNodes(int depth)
{
if (SanityManager.DEBUG)
{
super.printSubNodes(depth);
printLabel(depth, "javaNode: ");
javaNode.treePrint(depth + 1);
}
}
/**
* Get the JavaValueNode that lives under this JavaToSQLValueNode.
*
* @return The JavaValueNode that lives under this node.
*/
public JavaValueNode getJavaValueNode()
{
return javaNode;
}
/**
* @see QueryTreeNode#disablePrivilegeCollection
*/
public void disablePrivilegeCollection()
{
super.disablePrivilegeCollection();
if (javaNode != null)
javaNode.disablePrivilegeCollection();
}
/**
* Bind this expression. This means binding the sub-expressions,
* as well as figuring out what the return type is for this expression.
*
* @param fromList The FROM list for the query this
* expression is in, for binding columns.
* @param subqueryList The subquery list being built as we find
* SubqueryNodes
* @param aggregateVector The aggregate vector being built as we find AggregateNodes
*
* @return The new top of the expression tree.
*
* @exception StandardException Thrown on error
*/
public ValueNode bindExpression(FromList fromList, SubqueryList subqueryList,
Vector aggregateVector)
throws StandardException
{
// method invocations are not allowed in ADD TABLE clauses.
// And neither are field references.
javaNode.checkReliability(this);
/* Bind the expression under us */
javaNode = javaNode.bindExpression(fromList, subqueryList, aggregateVector);
DataTypeDescriptor dts = DataTypeDescriptor.getSQLDataTypeDescriptor(javaNode.getJavaTypeName());
if (dts == null)
{
throw StandardException.newException(SQLState.LANG_NO_CORRESPONDING_S_Q_L_TYPE,
javaNode.getJavaTypeName());
}
setType(dts);
return this;
}
/**
* Remap all ColumnReferences in this tree to be clones of the
* underlying expression.
*
* @return ValueNode The remapped expression tree.
*
* @exception StandardException Thrown on error
*/
public ValueNode remapColumnReferencesToExpressions()
throws StandardException
{
javaNode = javaNode.remapColumnReferencesToExpressions();
return this;
}
/**
* Categorize this predicate. Initially, this means
* building a bit map of the referenced tables for each predicate.
* If the source of this ColumnReference (at the next underlying level)
* is not a ColumnReference or a VirtualColumnNode then this predicate
* will not be pushed down.
*
* For example, in:
* select * from (select 1 from s) a (x) where x = 1
* we will not push down x = 1.
* NOTE: It would be easy to handle the case of a constant, but if the
* inner SELECT returns an arbitrary expression, then we would have to copy
* that tree into the pushed predicate, and that tree could contain
* subqueries and method calls.
*
* @param referencedTabs JBitSet with bit map of referenced FromTables
* @param simplePredsOnly Whether or not to consider method
* calls, field references and conditional nodes
* when building bit map
*
* @return boolean Whether or not source.expression is a ColumnReference
* or a VirtualColumnNode.
*
* @exception StandardException Thrown on error
*/
public boolean categorize(JBitSet referencedTabs, boolean simplePredsOnly)
throws StandardException
{
return javaNode.categorize(referencedTabs, simplePredsOnly);
}
/**
* Return the variant type for the underlying expression.
* The variant type can be:
* VARIANT - variant within a scan
* (method calls and non-static field access)
* SCAN_INVARIANT - invariant within a scan
* (column references from outer tables)
* QUERY_INVARIANT - invariant within the life of a query
* (constant expressions)
*
* @return The variant type for the underlying expression.
* @exception StandardException thrown on error
*/
protected int getOrderableVariantType() throws StandardException
{
return javaNode.getOrderableVariantType();
}
/**
* Accept a visitor, and call v.visit()
* on child nodes as necessary.
*
* @param v the visitor
*
* @exception StandardException on error
*/
public Visitable accept(Visitor v)
throws StandardException
{
Visitable returnNode = v.visit(this);
if (v.skipChildren(this))
{
return returnNode;
}
if (javaNode != null && !v.stopTraversal())
{
javaNode = (JavaValueNode)javaNode.accept(v);
}
return returnNode;
}
/**
* {@inheritDoc}
*/
protected boolean isEquivalent(ValueNode o)
{
// anything in the java domain is not equiavlent.
return false;
}
}