/*******************************************************************************
* 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 static org.eclipse.persistence.jpa.jpql.parser.Expression.COALESCE;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;
import org.eclipse.persistence.jpa.jpql.parser.CoalesceExpression;
import org.eclipse.persistence.jpa.jpql.parser.ScalarExpressionBNF;
import org.eclipse.persistence.jpa.jpql.tools.model.IListChangeListener;
import org.eclipse.persistence.jpa.jpql.utility.iterable.ListIterable;
import org.eclipse.persistence.jpa.jpql.utility.iterable.SnapshotCloneListIterable;
/**
* A <code><b>COALESCE</b></code> expression returns <code>null</code> if all its arguments evaluate
* to <code>null</code>, and the value of the first non-<code>null</code> argument otherwise.
* <p>
* The return type is the type returned by the arguments if they are all of the same type, otherwise
* it is undetermined.
*
* <div><b>BNF:</b> <code>coalesce_expression::= COALESCE(scalar_expression {, scalar_expression}+)</code></div>
*
* @see CoalesceExpression
*
* @version 2.4
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings("nls")
public class CoalesceExpressionStateObject extends AbstractEncapsulatedExpressionStateObject
implements ListHolderStateObject<StateObject> {
/**
* The state objects representing the scalar expressions.
*/
private List<StateObject> items;
/**
* Notifies the content of the state object list has changed.
*/
public static final String STATE_OBJECTS_LIST = "stateObjects";
/**
* Creates a new <code>CoalesceExpressionStateObject</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 CoalesceExpressionStateObject(StateObject parent) {
super(parent);
}
/**
* Creates a new <code>CoalesceExpressionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param items The list of {@link StateObject StateObjects} representing the encapsulated
* expressions
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public CoalesceExpressionStateObject(StateObject parent, List<StateObject> items) {
super(parent);
this.items = new ArrayList<>(parent(items));
}
/**
* Creates a new <code>CoalesceExpressionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param items The list of {@link StateObject StateObjects} representing the encapsulated
* expressions
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public CoalesceExpressionStateObject(StateObject parent, StateObject... items) {
super(parent);
this.items = new ArrayList<>();
Collections.addAll(this.items, parent(items));
}
/**
* Creates a new <code>CoalesceExpressionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param items The list of expression to parse into their {@link StateObject}
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public CoalesceExpressionStateObject(StateObject parent, String... items) {
super(parent);
this.items = new ArrayList<>();
parseItemInternal(items);
}
/**
* {@inheritDoc}
*/
public void accept(StateObjectVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildren(List<StateObject> children) {
super.addChildren(children);
children.addAll(items);
}
/**
* {@inheritDoc}
*/
public <S extends StateObject> S addItem(S item) {
getChangeSupport().addItem(this, items, STATE_OBJECTS_LIST, parent(item));
return item;
}
/**
* {@inheritDoc}
*/
public void addItems(List<? extends StateObject> items) {
getChangeSupport().addItems(this, this.items, STATE_OBJECTS_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(CoalesceExpressionStateObject 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);
}
/**
* {@inheritDoc}
*/
@Override
public CoalesceExpression getExpression() {
return (CoalesceExpression) super.getExpression();
}
/**
* {@inheritDoc}
*/
@Override
public String getIdentifier() {
return COALESCE;
}
/**
* {@inheritDoc}
*/
public StateObject getItem(int index) {
return items.get(index);
}
/**
* {@inheritDoc}
*/
public boolean hasItems() {
return !items.isEmpty();
}
/**
* {@inheritDoc}
*/
@Override
protected void initialize() {
super.initialize();
items = new ArrayList<StateObject>();
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEquivalent(StateObject stateObject) {
return super.isEquivalent(stateObject) &&
areChildrenEquivalent((CoalesceExpressionStateObject) 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, STATE_OBJECTS_LIST, item);
return item;
}
/**
* {@inheritDoc}
*/
public StateObject moveUp(StateObject item) {
getChangeSupport().moveUp(this, items, STATE_OBJECTS_LIST, item);
return item;
}
/**
* Parses the given JPQL fragment, which represents a single encapsulated expression, and creates
* the {@link StateObject}.
*
* @param jpqlFragment The portion of the query representing a single encapsulated expression
*/
public void parseItem(String jpqlFragment) {
StateObject stateObject = buildStateObject(jpqlFragment, ScalarExpressionBNF.ID);
addItem(stateObject);
}
/**
* Parses the given list of JPQL fragments, which represents each of the encapsulated expressions,
* and creates the {@link StateObject StateObjects}.
*
* @param items The list of expression to parse into their {@link StateObject}
*/
protected void parseItemInternal(String... items) {
for (String item : items) {
StateObject stateObject = buildStateObject(item, ScalarExpressionBNF.ID);
this.items.add(parent(stateObject));
}
}
/**
* Parses the given JPQL fragments, which represent individual expression, and creates the
* {@link StateObject StateObjects}.
*
* @param items The portion of the query representing a single encapsulated expression
*/
public void parseItems(ListIterator<String> items) {
while (items.hasNext()) {
StateObject stateObject = buildStateObject(items.next(), ScalarExpressionBNF.ID);
addItem(parent(stateObject));
}
}
/**
* Parses the given JPQL fragments, which represent individual expression, and creates the
* {@link StateObject StateObjects}.
*
* @param items The portion of the query representing a single encapsulated expression
*/
public void parseItems(String... items) {
for (String item : items) {
StateObject stateObject = buildStateObject(item, ScalarExpressionBNF.ID);
addItem(parent(stateObject));
}
}
/**
* {@inheritDoc}
*/
public void removeItem(StateObject item) {
getChangeSupport().removeItem(this, items, STATE_OBJECTS_LIST, item);
}
/**
* {@inheritDoc}
*/
public void removeItems(Collection<StateObject> items) {
getChangeSupport().removeItems(this, this.items, STATE_OBJECTS_LIST, items);
}
/**
* {@inheritDoc}
*/
public void removeListChangeListener(String listName, IListChangeListener<StateObject> listener) {
getChangeSupport().removeListChangeListener(listName, listener);
}
/**
* Keeps a reference of the {@link CoalesceExpression 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 CoalesceExpression parsed object} representing a <code><b>CASE</b></code>
* expression
*/
public void setExpression(CoalesceExpression expression) {
super.setExpression(expression);
}
/**
* {@inheritDoc}
*/
@Override
protected void toTextEncapsulatedExpression(Appendable writer) throws IOException {
toStringItems(writer, items, true);
}
}