oracle.toplink.essentials.internal.expressions.LiteralExpression Maven / Gradle / Ivy
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package oracle.toplink.essentials.internal.expressions;
import java.io.*;
import java.util.*;
import oracle.toplink.essentials.queryframework.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.internal.sessions.AbstractRecord;
import oracle.toplink.essentials.internal.sessions.AbstractSession;
/**
* Used for wrapping literal values.
*/
public class LiteralExpression extends Expression {
protected String value;
protected Expression localBase;
public LiteralExpression() {
super();
}
public LiteralExpression(String newValue, Expression baseExpression) {
super();
value = newValue;
localBase = baseExpression;
}
/**
* INTERNAL:
* Used for debug printing.
*/
public String descriptionOfNodeType() {
return "Literal";
}
/**
* 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() {
return getLocalBase().getBuilder();
}
protected Expression getLocalBase() {
return localBase;
}
public String getValue() {
return value;
}
public boolean isLiteralExpression() {
return true;
}
/**
* INTERNAL:
* Used for cloning.
*/
protected void postCopyIn(Dictionary alreadyDone) {
super.postCopyIn(alreadyDone);
localBase = localBase.copiedVersionFrom(alreadyDone);
}
/**
* INTERNAL:
* Print SQL onto the stream, using the ExpressionPrinter for context
*/
public void printSQL(ExpressionSQLPrinter printer) {
printer.printString(value);
}
/**
* INTERNAL:
* Print SQL, this is called from functions, so must not be converted through the mapping.
*/
public void printSQLWithoutConversion(ExpressionSQLPrinter printer) {
printSQL(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) {
Expression result = (LiteralExpression)clone();
result.setLocalBase(getLocalBase().rebuildOn(newBase));
return result;
}
public void setLocalBase(Expression e) {
localBase = e;
}
/**
* INTERNAL:
* Rebuild myself against the base, with the values of parameters supplied by the context
* expression. This is used for transforming a standalone expression (e.g. the join criteria of a mapping)
* into part of some larger expression. You normally would not call this directly, instead calling twist
* See the comment there for more details"
*/
public Expression twistedForBaseAndContext(Expression newBase, Expression context) {
return (Expression)this.clone();
}
/**
* INTERNAL:
* Return the value for in memory comparison.
* This is only valid for valueable expressions.
*/
public Object valueFromObject(Object object, AbstractSession session, AbstractRecord translationRow, InMemoryQueryIndirectionPolicy valueHolderPolicy, boolean isObjectUnregistered) {
return getLocalBase().getFieldValue(getValue());
}
/**
* INTERNAL:
* Used to print a debug form of the expression tree.
*/
public void writeDescriptionOn(BufferedWriter writer) throws IOException {
writer.write(getValue().toString());
}
}