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package oracle.toplink.essentials.internal.expressions;
import java.io.*;
import java.util.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.queryframework.*;
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.internal.databaseaccess.*;
import oracle.toplink.essentials.internal.sessions.AbstractRecord;
import oracle.toplink.essentials.internal.sessions.AbstractSession;
/**
* <p><b>Purpose</b>: Expression SQL printer.
* <p><b>Responsibilities</b>:<ul>
* <li> Print an expression in SQL format.
* <li> Replaces FIELD types with field names from the descriptor.
* <li> Replaces PARAMETER types with row or object values.
* <li> Calls accessor to print primitive types.
* </ul>
* @author Dorin Sandu
* @since TOPLink/Java 1.0
*/
public class ExpressionSQLPrinter {
/**
* Stores the current session. The session accessor
* is used to print all the primitive types.
*/
protected AbstractSession session;
/**
* Stores the call being created.
*/
protected SQLCall call;
/**
* Stores the row. Used to print PARAMETER nodes.
*/
protected AbstractRecord translationRow;
/**
* Indicates whether fully qualified field names
* (owner + table) should be used or not.
*/
protected boolean shouldPrintQualifiedNames;
// What we write on
protected Writer writer;
/** Used for distincts in functions. */
protected boolean requiresDistinct;
// Used in figuring out when to print a comma in the select line
protected boolean isFirstElementPrinted;
public ExpressionSQLPrinter(AbstractSession session, AbstractRecord translationRow, SQLCall call, boolean printQualifiedNames) {
this.session = session;
this.translationRow = translationRow;
this.call = call;
this.shouldPrintQualifiedNames = printQualifiedNames;
this.requiresDistinct = false;
isFirstElementPrinted = false;
}
/**
* Return the call.
*/
protected SQLCall getCall() {
return call;
}
/**
* INTERNAL:
* Return the database platform specific information.
*/
public DatabasePlatform getPlatform() {
return session.getPlatform();
}
protected AbstractSession getSession() {
return session;
}
/**
* INTERNAL:
* Return the row for translation
*/
protected AbstractRecord getTranslationRow() {
return translationRow;
}
public Writer getWriter() {
return writer;
}
/**
* INTERNAL:
* Used in figuring out when to print a comma in the select clause
*/
public boolean isFirstElementPrinted() {
return isFirstElementPrinted;
}
public void printExpression(Expression expression) {
translateExpression(expression);
}
public void printField(DatabaseField field) {
if (field == null) {
return;
}
try {
// Print the field using either short or long notation i.e. owner + table name.
if (shouldPrintQualifiedNames()) {
getWriter().write(field.getQualifiedName());
} else {
getWriter().write(field.getName());
}
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
public void printParameter(ParameterExpression expression) {
try {
getCall().appendTranslationParameter(getWriter(), expression, getPlatform());
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
public void printParameter(DatabaseField field) {
getCall().appendTranslation(getWriter(), field);
}
public void printPrimitive(Object value) {
if (value instanceof Vector) {
printValuelist((Vector)value);
return;
}
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), value);
}
public void printNull(ConstantExpression nullValueExpression) {
if(session.getPlatform().shouldBindLiterals()) {
DatabaseField field = null;
Expression localBase = nullValueExpression.getLocalBase();
if(localBase.isFieldExpression()) {
field = ((FieldExpression)localBase).getField();
} else if(localBase.isQueryKeyExpression()) {
field = ((QueryKeyExpression)localBase).getField();
}
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), field);
} else {
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), null);
}
}
public void printString(String value) {
try {
getWriter().write(value);
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
public void printValuelist(Vector values) {
try {
Enumeration valuesEnum = values.elements();
while (valuesEnum.hasMoreElements()) {
Object value = valuesEnum.nextElement();
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), value);
if (valuesEnum.hasMoreElements()) {
getWriter().write(", ");
}
}
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
/**
* If a distinct has been set the DISTINCT clause will be printed.
* This is required for batch reading.
*/
public boolean requiresDistinct() {
return requiresDistinct;
}
protected void setCall(SQLCall call) {
this.call = call;
}
/**
* INTERNAL:
* Used in figuring out when to print a comma in the select clause
*/
public void setIsFirstElementPrinted(boolean isFirstElementPrinted) {
this.isFirstElementPrinted = isFirstElementPrinted;
}
/**
* If a distinct has been set the DISTINCT clause will be printed.
* This is required for batch reading.
*/
public void setRequiresDistinct(boolean requiresDistinct) {
this.requiresDistinct = requiresDistinct;
}
protected void setSession(AbstractSession theSession) {
session = theSession;
}
protected void setShouldPrintQualifiedNames(boolean shouldPrintQualifiedNames) {
this.shouldPrintQualifiedNames = shouldPrintQualifiedNames;
}
/**
* INTERNAL:
* Set the row for translation
*/
protected void setTranslationRow(AbstractRecord theRow) {
translationRow = theRow;
}
public void setWriter(Writer writer) {
this.writer = writer;
}
public boolean shouldPrintParameterValues() {
return getTranslationRow() != null;
}
protected boolean shouldPrintQualifiedNames() {
return shouldPrintQualifiedNames;
}
/**
* Translate an expression i.e. call the appropriate
* translation method for the expression based on its
* type. The translation method is then responsible
* for translating the subexpressions.
*/
protected void translateExpression(Expression theExpression) {
theExpression.printSQL(this);
}
}
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