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package oracle.toplink.essentials.internal.expressions;
import java.io.*;
import java.util.*;
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.internal.databaseaccess.*;
/**
* Abstract class for expression that have exactly two children, such as and/or and relations.
*/
public abstract class CompoundExpression extends Expression {
protected ExpressionOperator operator;
protected transient ExpressionOperator platformOperator;
protected Expression firstChild;
protected Expression secondChild;
public CompoundExpression() {
super();
}
/**
* INTERNAL:
* Find the alias for a given table from the first or second child in the additionalOuterJoinCriteria
*/
public DatabaseTable aliasForTable(DatabaseTable table) {
DatabaseTable alias = null;
if (getFirstChild() != null) {
alias = getFirstChild().aliasForTable(table);
}
if ((alias == null) && (getSecondChild() != null)) {
alias = getSecondChild().aliasForTable(table);
}
return alias;
}
/**
* INTERNAL:
*/
public Expression create(Expression base, Object singleArgument, ExpressionOperator operator) {
setFirstChild(base);
Expression argument = Expression.from(singleArgument, base);
setSecondChild(argument);
setOperator(operator);
return this;
}
/**
* INTERNAL:
*/
public Expression create(Expression base, Vector arguments, ExpressionOperator operator) {
setFirstChild(base);
if (!arguments.isEmpty()) {
setSecondChild((Expression)arguments.firstElement());
}
setOperator(operator);
return this;
}
/**
* INTERNAL:
* Used for debug printing.
*/
public String descriptionOfNodeType() {
return "Compound Expression";
}
/**
* Return the expression builder which is the ultimate base of this expression, or
* null if there isn't one (shouldn't happen if we start from a root)
*/
public ExpressionBuilder getBuilder() {
ExpressionBuilder builder = getFirstChild().getBuilder();
if (builder == null) {
return getSecondChild().getBuilder();
} else {
return builder;
}
}
public Expression getFirstChild() {
return firstChild;
}
public ExpressionOperator getOperator() {
return operator;
}
public ExpressionOperator getPlatformOperator(DatabasePlatform platform) {
if (platformOperator == null) {
initializePlatformOperator(platform);
}
return platformOperator;
}
public Expression getSecondChild() {
return secondChild;
}
/**
* INTERNAL:
*/
public void initializePlatformOperator(DatabasePlatform platform) {
if (getOperator().isComplete()) {
platformOperator = getOperator();
return;
}
platformOperator = platform.getOperator(getOperator().getSelector());
if (platformOperator == null) {
throw QueryException.invalidOperator(getOperator().toString());
}
}
public boolean isCompoundExpression() {
return true;
}
/**
* INTERNAL:
* For iterating using an inner class
*/
public void iterateOn(ExpressionIterator iterator) {
super.iterateOn(iterator);
if (getFirstChild() != null) {
getFirstChild().iterateOn(iterator);
}
if (getSecondChild() != null) {
getSecondChild().iterateOn(iterator);
}
}
/**
* INTERNAL:
* Normalize into a structure that is printable.
* Also compute printing information such as outer joins.
*/
public Expression normalize(ExpressionNormalizer normalizer) {
validateNode();
if (getFirstChild() != null) {
//let's make sure a session is available in the case of a parallel expression
ExpressionBuilder builder = getFirstChild().getBuilder();
if (builder != null){
builder.setSession(normalizer.getSession().getRootSession(null));
}
setFirstChild(getFirstChild().normalize(normalizer));
}
if (getSecondChild() != null) {
//let's make sure a session is available in the case of a parallel expression
ExpressionBuilder builder = getSecondChild().getBuilder();
if (builder != null){
builder.setSession(normalizer.getSession().getRootSession(null));
}
setSecondChild(getSecondChild().normalize(normalizer));
}
// For CR2456, it is now possible for normalize to remove redundant
// conditions from the where clause.
if (getFirstChild() == null) {
return getSecondChild();
} else if (getSecondChild() == null) {
return getFirstChild();
}
return this;
}
/**
* Do any required validation for this node. Throw an exception if it's incorrect.
* Ensure that both sides are not data expressions.
*/
public void validateNode() {
if (getFirstChild() != null) {
if (getFirstChild().isDataExpression() || getFirstChild().isConstantExpression()) {
throw QueryException.invalidExpression(this);
}
}
if (getSecondChild() != null) {
if (getSecondChild().isDataExpression() || getSecondChild().isConstantExpression()) {
throw QueryException.invalidExpression(this);
}
}
}
/**
* INTERNAL:
* Used for cloning.
*/
protected void postCopyIn(Dictionary alreadyDone) {
super.postCopyIn(alreadyDone);
if (getFirstChild() != null) {
setFirstChild(getFirstChild().copiedVersionFrom(alreadyDone));
}
if (getSecondChild() != null) {
setSecondChild(getSecondChild().copiedVersionFrom(alreadyDone));
}
}
/**
* INTERNAL:
* Print SQL
*/
public void printSQL(ExpressionSQLPrinter printer) {
ExpressionOperator realOperator = getPlatformOperator(printer.getPlatform());
printer.printString("(");
realOperator.printDuo(getFirstChild(), getSecondChild(), printer);
printer.printString(")");
}
/**
* INTERNAL:
* Print java for project class generation
*/
public void printJava(ExpressionJavaPrinter printer) {
ExpressionOperator realOperator = getPlatformOperator(printer.getPlatform());
realOperator.printJavaDuo(getFirstChild(), getSecondChild(), printer);
}
/**
* INTERNAL:
* This expression is built on a different base than the one we want. Rebuild it and
* return the root of the new tree
*/
public Expression rebuildOn(Expression newBase) {
Vector arguments;
Expression first = getFirstChild().rebuildOn(newBase);
if (getSecondChild() == null) {
arguments = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance(0);
} else {
arguments = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance(1);
arguments.addElement(getSecondChild().rebuildOn(newBase));
}
return first.performOperator(getOperator(), arguments);
}
protected void setFirstChild(Expression firstChild) {
this.firstChild = firstChild;
}
public void setOperator(ExpressionOperator newOperator) {
operator = newOperator;
}
protected void setSecondChild(Expression secondChild) {
this.secondChild = secondChild;
}
/**
* INTRENAL:
* Used to change an expression off of one base to an expression off of a different base.
* i.e. expression on address to an expression on an employee's address.
*/
public Expression twistedForBaseAndContext(Expression newBase, Expression context) {
Vector arguments;
if (getSecondChild() == null) {
arguments = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance(0);
} else {
arguments = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance(1);
arguments.addElement(getSecondChild().twistedForBaseAndContext(newBase, context));
}
Expression first = getFirstChild().twistedForBaseAndContext(newBase, context);
return first.performOperator(getOperator(), arguments);
}
/**
* INTERNAL:
* Used to print a debug form of the expression tree.
*/
public void writeDescriptionOn(BufferedWriter writer) throws IOException {
writer.write(operator.toString());
}
/**
* INTERNAL:
* Used for toString for debugging only.
*/
public void writeSubexpressionsTo(BufferedWriter writer, int indent) throws IOException {
if (getFirstChild() != null) {
getFirstChild().toString(writer, indent);
}
if (getSecondChild() != null) {
getSecondChild().toString(writer, indent);
}
}
}
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