/*******************************************************************************
* Copyright (c) 2011, 2015 Oracle and/or its affiliates. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation
*
******************************************************************************/
package org.eclipse.persistence.jpa.jpql.tools.model.query;
import java.io.IOException;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.parser.ResultVariable;
import org.eclipse.persistence.jpa.jpql.parser.SelectExpressionBNF;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;
import static org.eclipse.persistence.jpa.jpql.parser.Expression.*;
/**
* A result variable may be used to name a select item in the query result.
*
* <div><b>BNF:</b> <code>select_item ::= select_expression [[AS] result_variable]</code><p></div>
*
* @see ResultVariable
*
* @version 2.4
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings({"nls", "unused"}) // unused used for the import statement: see bug 330740
public class ResultVariableStateObject extends AbstractStateObject {
/**
* Flag used to determine if the <code><b>AS</b></code> identifier is used or not.
*/
private boolean as;
/**
* The result variable identifies the select expression, which can be used in the
* <code><b>ORDER BY</b></code> clause.
*/
private IdentificationVariableStateObject resultVariable;
/**
* The state object representing the select expression that is named with a result variable.
*/
private StateObject stateObject;
/**
* Notifies the visibility of the <code><b>AS</b></code> identifier has changed.
*/
public static final String AS_PROPERTY = "as";
/**
* Notifies the result variable property has changed.
*/
public static final String RESULT_VARIABLE_PROPERTY = "resultVariable";
/**
* Notifies the select state object property has changed.
*/
public static final String STATE_OBJECT_PROPERTY = "selectStateObject";
/**
* Creates a new <code>ResultVariableStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public ResultVariableStateObject(SelectClauseStateObject parent) {
super(parent);
}
/**
* Creates a new <code>ResultVariableStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param stateObject The {@link StateObject} representing the select item
* @param as Determines whether the <code><b>AS</b></code> identifier is used or not
* @param resultVariable The variable identifying the select item
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public ResultVariableStateObject(SelectClauseStateObject parent,
StateObject stateObject,
boolean as,
String resultVariable) {
super(parent);
this.as = as;
this.stateObject = parent(stateObject);
this.resultVariable.setTextInternally(resultVariable);
}
/**
* Creates a new <code>ResultVariableStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param stateObject The {@link StateObject} representing the select item
* @param resultVariable The variable identifying the select item
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public ResultVariableStateObject(SelectClauseStateObject parent,
StateObject stateObject,
String resultVariable) {
this(parent, stateObject, false, resultVariable);
}
/**
* {@inheritDoc}
*/
public void accept(StateObjectVisitor visitor) {
visitor.visit(this);
}
/**
* Makes sure the <code><b>AS</b></code> identifier is used.
*
* @return This object
*/
public ResultVariableStateObject addAs() {
if (!as) {
setAs(true);
}
return this;
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildren(List<StateObject> children) {
super.addChildren(children);
if (stateObject != null) {
children.add(stateObject);
}
children.add(resultVariable);
}
/**
* {@inheritDoc}
*/
@Override
public ResultVariable getExpression() {
return (ResultVariable) super.getExpression();
}
/**
* {@inheritDoc}
*/
@Override
public SelectClauseStateObject getParent() {
return (SelectClauseStateObject) super.getParent();
}
/**
* Returns the result variable identifies the select expression, which can be used in the
* <code><b>ORDER BY</b></code> clause.
*
* @return The unique identifier declaring the select expression
*/
public String getResultVariable() {
return resultVariable.getText();
}
/**
* Returns the {@link StateObject} representing a single select expression.
*
* @return The {@link StateObject} representing a single select expression
*/
public StateObject getStateObject() {
return stateObject;
}
/**
* Determines whether the <code><b>AS</b></code> identifier is used.
*
* @return <code>true</code> if the <code><b>AS</b></code> identifier is used; <code>false</code>
* otherwise
*/
public boolean hasAs() {
return as;
}
/**
* Determines whether the result variable has been defined.
*
* @return <code>true</code> if the result variable is defined; <code>false</code> otherwise
*/
public boolean hasResultVariable() {
return resultVariable.hasText();
}
/**
* Determines whether the select item has been defined.
*
* @return <code>true</code> if there the selected expression has been defined; <code>false</code>
* if it's missing
*/
public boolean hasStateObject() {
return stateObject != null;
}
/**
* {@inheritDoc}
*/
@Override
protected void initialize() {
super.initialize();
resultVariable = new IdentificationVariableStateObject(this);
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEquivalent(StateObject stateObject) {
if (super.isEquivalent(stateObject)) {
ResultVariableStateObject resultVariable = (ResultVariableStateObject) stateObject;
return as == resultVariable.as &&
resultVariable.isEquivalent(resultVariable.resultVariable) &&
areEquivalent(stateObject, resultVariable.stateObject);
}
return false;
}
/**
* Parses the given JPQL fragment, which represents a single select expression, and creates the
* {@link StateObject}.
*
* @param jpqlFragment The portion of the query representing a single select expression
*/
public void parse(String jpqlFragment) {
StateObject stateObject = buildStateObject(jpqlFragment, SelectExpressionBNF.ID);
setStateObject(stateObject);
}
/**
* Makes sure the <code><b>AS</b></code> identifier is not used.
*/
public void removeAs() {
if (as) {
setAs(true);
}
}
/**
* Sets whether the <code><b>AS</b></code> identifier should be used.
*
* @param as <code>true</code> if the <code><b>AS</b></code> identifier should be used part;
* <code>false</code> otherwise
*/
public void setAs(boolean as) {
boolean oldAs = this.as;
this.as = as;
firePropertyChanged(AS_PROPERTY, oldAs, as);
}
/**
* Keeps a reference of the {@link ResultVariable parsed object} object, which should only be
* done when this object is instantiated during the conversion of a parsed JPQL query into
* {@link StateObject StateObjects}.
*
* @param expression The {@link ResultVariable parsed object} representing a result variable
* expression
*/
public void setExpression(ResultVariable expression) {
super.setExpression(expression);
}
/**
* Sets the result variable that identifies the select expression, which can be used in the
* <code><b>ORDER BY</b></code> clause.
*
* @param resultVariable The unique identifier declaring the select expression
*/
public void setResultVariable(String resultVariable) {
String oldResultVariable = getResultVariable();
this.resultVariable.setText(resultVariable);
firePropertyChanged(RESULT_VARIABLE_PROPERTY, oldResultVariable, resultVariable);
}
/**
* Sets the {@link StateObject} representing a single select expression.
*
* @param stateObject The {@link StateObject} representing a single select expression
*/
public void setStateObject(StateObject stateObject) {
StateObject oldStateObject = this.stateObject;
this.stateObject = parent(stateObject);
firePropertyChanged(STATE_OBJECT_PROPERTY, oldStateObject, stateObject);
}
/**
* Toggles the visibility of the <code><b>AS</b></code> identifier; either adds it if it's not
* present otherwise removes it if it's present.
*/
public void toggleAs() {
setAs(!as);
}
/**
* {@inheritDoc}
*/
@Override
protected void toTextInternal(Appendable writer) throws IOException {
if (stateObject != null) {
stateObject.toString(writer);
writer.append(SPACE);
}
if (as) {
writer.append(AS);
}
if (hasResultVariable()) {
writer.append(SPACE);
resultVariable.toTextInternal(writer);
}
}
}