/*******************************************************************************
* 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.ArrayList;
import java.util.Collection;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.parser.InternalSelectExpressionBNF;
import org.eclipse.persistence.jpa.jpql.parser.SelectClause;
import org.eclipse.persistence.jpa.jpql.parser.SelectExpressionBNF;
import org.eclipse.persistence.jpa.jpql.tools.model.IListChangeListener;
import org.eclipse.persistence.jpa.jpql.tools.model.ISelectExpressionStateObjectBuilder;
import org.eclipse.persistence.jpa.jpql.utility.iterable.ListIterable;
import org.eclipse.persistence.jpa.jpql.utility.iterable.SnapshotCloneListIterable;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;
import static org.eclipse.persistence.jpa.jpql.parser.Expression.*;
/**
* The <code><b>SELECT</b></code> statement queries data from entities, which determines the type of
* the objects or values to be selected.
*
* <pre><code>BNF: select_clause ::= SELECT [DISTINCT] select_expression {, select_expression}*
* select_expression ::= single_valued_path_expression |
* aggregate_expression |
* identification_variable |
* OBJECT(identification_variable) |
* constructor_expression</code></pre>
*
* @see SelectStatementStateObject
* @see SelectClause
*
* @version 2.4
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings({"nls", "unused"}) // unused used for the import statement: see bug 330740
public class SelectClauseStateObject extends AbstractSelectClauseStateObject
implements ListHolderStateObject<StateObject> {
/**
* The builder is cached during the creation of the select expression.
*/
private ISelectExpressionStateObjectBuilder builder;
/**
* The list of select expressions.
*/
private List<StateObject> items;
/**
* A constant used to notify the list of select expressions has changed.
*/
public static final String SELECT_ITEMS_LIST = "selectItems";
/**
* Creates a new <code>SelectClauseStateObject</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 SelectClauseStateObject(SelectStatementStateObject parent) {
super(parent);
}
/**
* {@inheritDoc}
*/
public void accept(StateObjectVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildren(List<StateObject> children) {
super.addChildren(children);
children.addAll(items);
}
/**
* Adds the given {@link StateObject} as a select item.
*
* @param stateObject The {@link StateObject} representing the select expression
* @param resultVariable The result variable identifying the select expression
* @return The newly created {@link ResultVariableStateObject}
*/
public ResultVariableStateObject addItem(StateObject stateObject, String resultVariable) {
ResultVariableStateObject item = new ResultVariableStateObject(
this,
stateObject,
false,
resultVariable
);
addItem(item);
return item;
}
/**
* Adds the given path as a select item, which can either be an identification variable or a
* state-field path expression.
*
* @param jpqlFragment The select expression to parse as a select item
* @return The {@link StateObject} encapsulating the given path
*/
public StateObject addItem(String jpqlFragment) {
StateObject item = buildStateObject(jpqlFragment, SelectExpressionBNF.ID);
addItem(item);
return item;
}
/**
* Adds the given expression as a select item.
*
* @param jpqlFragment The select expression to parse as a select item
* @param resultVariable The result variable identifying the select expression
* @return The newly created {@link ResultVariableStateObject}
*/
public ResultVariableStateObject addItem(String jpqlFragment, String resultVariable) {
ResultVariableStateObject item = new ResultVariableStateObject(this);
item.parse(jpqlFragment);
item.setResultVariable(resultVariable);
addItem(item);
return item;
}
/**
* {@inheritDoc}
*/
public <S extends StateObject> S addItem(S item) {
getChangeSupport().addItem(this, items, SELECT_ITEMS_LIST, parent(item));
return item;
}
/**
* Adds the given {@link StateObject} as a select item.
*
* @param stateObject The {@link StateObject} representing the select expression
* @param resultVariable The result variable identifying the select expression
* @return The newly created {@link ResultVariableStateObject}
*/
public ResultVariableStateObject addItemAs(StateObject stateObject, String resultVariable) {
ResultVariableStateObject item = new ResultVariableStateObject(
this,
stateObject,
true,
resultVariable
);
addItem(item);
return item;
}
/**
* Adds the given JPQL fragment as a select item.
*
* @param jpqlFragment The portion of a JPQL query that represents a select expression
* @param resultVariable The result variable identifying the select expression
* @return The newly created {@link ResultVariableStateObject}
*/
public ResultVariableStateObject addItemAs(String jpqlFragment, String resultVariable) {
ResultVariableStateObject item = new ResultVariableStateObject(this);
item.addAs();
item.parse(jpqlFragment);
item.setResultVariable(resultVariable);
addItem(item);
return item;
}
/**
* {@inheritDoc}
*/
public void addItems(List<? extends StateObject> items) {
getChangeSupport().addItems(this, this.items, SELECT_ITEMS_LIST, parent(items));
}
/**
* {@inheritDoc}
*/
public void addListChangeListener(String listName, IListChangeListener<StateObject> listener) {
getChangeSupport().addListChangeListener(listName, listener);
}
/**
* Determines whether the children of this {@link StateObject} are equivalent to the children
* of the given one, i.e. the information of the {@link StateObject StateObjects} is the same.
*
* @param stateObject The {@link StateObject} to compare its children to this one's children
* @return <code>true</code> if both have equivalent children; <code>false</code> otherwise
*/
protected boolean areChildrenEquivalent(SelectClauseStateObject stateObject) {
int size = itemsSize();
if (size != stateObject.itemsSize()) {
return false;
}
for (int index = size; --index >= 0; ) {
StateObject child1 = getItem(index);
StateObject child2 = stateObject.getItem(index);
if (!child1.isEquivalent(child2)) {
return false;
}
}
return true;
}
/**
* {@inheritDoc}
*/
public boolean canMoveDown(StateObject item) {
return getChangeSupport().canMoveDown(items, item);
}
/**
* {@inheritDoc}
*/
public boolean canMoveUp(StateObject item) {
return getChangeSupport().canMoveUp(items, item);
}
/**
* Creates and returns a new {@link ISelectExpressionStateObjectBuilder} that can be used to
* programmatically create a single select expression and once the expression is complete,
* {@link ISelectExpressionStateObjectBuilder#commit()} will push the {@link StateObject}
* representation of that expression as this clause's select expression.
*
* @return A new builder that can be used to quickly create a select expression
*/
public ISelectExpressionStateObjectBuilder getBuilder() {
if (builder == null) {
builder = getQueryBuilder().buildStateObjectBuilder(this);
}
return builder;
}
/**
* {@inheritDoc}
*/
@Override
public SelectClause getExpression() {
return (SelectClause) super.getExpression();
}
/**
* {@inheritDoc}
*/
@Override
public FromClauseStateObject getFromClause() {
return (FromClauseStateObject) super.getFromClause();
}
/**
* {@inheritDoc}
*/
public StateObject getItem(int index) {
return items.get(index);
}
/**
* {@inheritDoc}
*/
@Override
public SelectStatementStateObject getParent() {
return (SelectStatementStateObject) super.getParent();
}
/**
* {@inheritDoc}
*/
public boolean hasItems() {
return items.size() > 0;
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasSelectItem() {
return hasItems();
}
/**
* {@inheritDoc}
*/
@Override
protected void initialize() {
super.initialize();
items = new ArrayList<StateObject>();
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEquivalent(StateObject stateObject) {
return super.isEquivalent(stateObject) &&
areChildrenEquivalent((SelectClauseStateObject) stateObject);
}
/**
* {@inheritDoc}
*/
public ListIterable<StateObject> items() {
return new SnapshotCloneListIterable<StateObject>(items);
}
/**
* {@inheritDoc}
*/
public int itemsSize() {
return items.size();
}
/**
* {@inheritDoc}
*/
public StateObject moveDown(StateObject item) {
getChangeSupport().moveDown(this, items, SELECT_ITEMS_LIST, item);
return item;
}
/**
* {@inheritDoc}
*/
public StateObject moveUp(StateObject item) {
getChangeSupport().moveUp(this, items, SELECT_ITEMS_LIST, item);
return item;
}
/**
* {@inheritDoc}
*/
@Override
public void parse(String jpqlFragment) {
List<StateObject> stateObjects = buildStateObjects(jpqlFragment, InternalSelectExpressionBNF.ID);
addItems(stateObjects);
}
/**
* {@inheritDoc}
*/
public void removeItem(StateObject stateObject) {
getChangeSupport().removeItem(this, items, SELECT_ITEMS_LIST, stateObject);
}
/**
* {@inheritDoc}
*/
public void removeItems(Collection<StateObject> items) {
getChangeSupport().removeItems(this, this.items, SELECT_ITEMS_LIST, items);
}
/**
* {@inheritDoc}
*/
public void removeListChangeListener(String listName, IListChangeListener<StateObject> listener) {
getChangeSupport().removeListChangeListener(listName, listener);
}
/**
* Keeps a reference of the {@link SelectClause 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 SelectClause parsed object} representing a <code><b>SELECT</b></code>
* clause
*/
public void setExpression(SelectClause expression) {
super.setExpression(expression);
}
/**
* Sets the select expression to be those contained on the given collection. If any select items
* were already set, they will be removed.
*
* @param stateObjects The new select expressions
*/
public void setItems(List<StateObject> stateObjects) {
builder = null;
getChangeSupport().replaceItems(this, items, SELECT_ITEMS_LIST, stateObjects);
}
/**
* {@inheritDoc}
*/
@Override
protected void toTextInternal(Appendable writer) throws IOException {
// 'SELECT'
writer.append(SELECT);
// 'DISTINCT'
if (hasDistinct()) {
writer.append(SPACE);
writer.append(DISTINCT);
}
// Select items
if (hasItems()) {
writer.append(SPACE);
toStringItems(writer, items, true);
}
}
}