org.apache.jackrabbit.spi.commons.query.OrderQueryNode Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jackrabbit.spi.commons.query;
import org.apache.jackrabbit.spi.Name;
import org.apache.jackrabbit.spi.Path;
import org.apache.jackrabbit.spi.commons.conversion.MalformedPathException;
import org.apache.jackrabbit.spi.commons.name.PathBuilder;
import javax.jcr.RepositoryException;
import java.util.ArrayList;
import java.util.List;
/**
* Implements a query node that defines the order of nodes according to the
* values of properties.
*/
public class OrderQueryNode extends QueryNode {
/**
* The order specs
*/
private final List specs = new ArrayList();
/**
* Creates a new OrderQueryNode with a reference to a parent
* node and sort properties.
*
* @param parent the parent node of this query node.
*/
protected OrderQueryNode(QueryNode parent) {
super(parent);
}
/**
* Returns the type of this node.
*
* @return the type of this node.
*/
public int getType() {
return QueryNode.TYPE_ORDER;
}
/**
* Create and add a new (empty) order specification to this query node.
*/
public void newOrderSpec() {
specs.add(new OrderSpec((Path) null, true));
}
/**
* Set the last order specification of this query node to ascending/descending
* @see OrderSpec#setAscending(boolean)
*
* @param value true for ascending and false for
* descending.
* @throws IllegalStateException if no order specification is set
*/
public void setAscending(boolean value) {
if (specs.size() == 0) {
throw new IllegalStateException("No order specification set");
}
OrderSpec orderSpec = specs.get(specs.size() - 1);
orderSpec.setAscending(value);
}
/**
* Set the path of the last order specification of this query node.
* @see OrderSpec#setPath(org.apache.jackrabbit.spi.Path)
*
* @param path a path
* @throws IllegalStateException if no order specification is set
*/
public void setPath(Path path) {
if (specs.size() == 0) {
throw new IllegalStateException("No order specification set");
}
OrderSpec orderSpec = specs.get(specs.size() - 1);
orderSpec.setPath(path);
}
/**
* Set the function of the last order specification of this query node.
* @see OrderSpec#setFunction(String)
*
* @param name a function name
* @throws IllegalStateException if no order specification is set
*/
public void setFunction(String name) {
if (specs.size() == 0) {
throw new IllegalStateException("No order specification set");
}
OrderSpec orderSpec = specs.get(specs.size() - 1);
orderSpec.setFunction(name);
}
/**
* Checks whether all order specifications of this query node have at least
* its path specified (i.e. non null.)
*
* @return true iff all order specification of this query node are valid.
*/
public boolean isValid() {
for (OrderSpec spec : specs) {
if (spec.getPropertyPath() == null) {
return false;
}
}
return true;
}
/**
* Adds an order specification to this query node.
*
* @param property the name of the property.
* @param ascending if true values of this properties are
* ordered ascending; descending if false.
* @deprecated use {@link #addOrderSpec(Path , boolean)} instead.
*/
public void addOrderSpec(Name property, boolean ascending) {
addOrderSpec(createPath(property), ascending);
}
/**
* Adds an order specification to this query node.
*
* @param property the relative path of the property.
* @param ascending if true values of this properties are
* ordered ascending; descending if false.
*/
public void addOrderSpec(Path property, boolean ascending) {
specs.add(new OrderSpec(property, ascending));
}
/**
* Adds an order specification to this query node.
*
* @param spec the order spec.
*/
public void addOrderSpec(OrderSpec spec) {
specs.add(spec);
}
/**
* {@inheritDoc}
* @throws RepositoryException
*/
public Object accept(QueryNodeVisitor visitor, Object data) throws RepositoryException {
return visitor.visit(this, data);
}
/**
* Returns true if the property i should be ordered
* ascending. If false the property is ordered descending.
*
* @param i index of the property
* @return the order spec for the property i.
* @throws IndexOutOfBoundsException if there is no property with
* index i.
*/
public boolean isAscending(int i) throws IndexOutOfBoundsException {
return specs.get(i).ascending;
}
/**
* Returns a OrderSpec array that contains order by
* specifications.
*
* @return order by specs.
*/
public OrderSpec[] getOrderSpecs() {
return specs.toArray(new OrderSpec[specs.size()]);
}
/**
* {@inheritDoc}
*/
public boolean equals(Object obj) {
if (obj instanceof OrderQueryNode) {
OrderQueryNode other = (OrderQueryNode) obj;
return specs.equals(other.specs);
}
return false;
}
//------------------< OrderSpec class >-------------------------------------
/**
* Implements a single order specification. Contains a property name
* and whether it is ordered ascending or descending.
*/
public static final class OrderSpec {
/**
* The relative path to of the property
*/
private Path property;
/**
* If true this property is ordered ascending
*/
private boolean ascending;
/**
* The function applied to the property
*/
private String function;
/**
* Creates a new OrderSpec for property.
*
* @param property the name of the property.
* @param ascending if true the property is ordered
* ascending, otherwise descending.
* @deprecated use {@link OrderSpec#OrderSpec(Path, boolean)} instead.
*/
public OrderSpec(Name property, boolean ascending) {
this(createPath(property), ascending);
}
/**
* Creates a new OrderSpec for property.
*
* @param property the relative path of the property.
* @param ascending if true the property is ordered
* ascending, otherwise descending.
*/
public OrderSpec(Path property, boolean ascending) {
this.property = property;
this.ascending = ascending;
}
/**
* Returns the name of the property.
*
* @return the name of the property.
* @deprecated use {@link #getPropertyPath()} instead.
*/
public Name getProperty() {
return property.getName();
}
/**
* Returns the relative path of the property.
*
* @return the relative path of the property.
*/
public Path getPropertyPath() {
return property;
}
/**
* If true the property is ordered ascending, otherwise
* descending.
*
* @return true for ascending; false for
* descending.
*/
public boolean isAscending() {
return ascending;
}
/**
* Sets the new value for the ascending property.
*
* @param ascending true for ascending; false
* for descending.
*/
public void setAscending(boolean ascending) {
this.ascending = ascending;
}
/**
* Set a new value for the path
*
* @param path a path
*/
public void setPath(Path path) {
this.property = path;
}
/**
* Set a new value for a function
*
* @param name a function name
*/
public void setFunction(String name) {
this.function = name;
}
/**
* @return name of the function
*/
public String getFunction() {
return function;
}
/**
* Returns true if this order spec is equal
* to obj
* @param obj the reference object with which to compare.
* @return true if this order spec is equal
* to obj; false otherwise.
*/
public boolean equals(Object obj) {
if (obj instanceof OrderSpec) {
OrderSpec other = (OrderSpec) obj;
return (property == null ? other.property == null : property.equals(other.property))
&& ascending == other.ascending;
}
return false;
}
}
/**
* {@inheritDoc}
*/
public boolean needsSystemTree() {
return false;
}
//--------------------------------< internal >------------------------------
/**
* Creates a path with a single element out of the given name.
*
* @param name the name to create the path from.
* @return a path with a single element.
*/
private static Path createPath(Name name) {
try {
PathBuilder builder = new PathBuilder();
builder.addLast(name);
return builder.getPath();
} catch (MalformedPathException e) {
// never happens, we just added an element
throw new InternalError();
}
}
}