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Cayenne Object Persistence Framework
/*****************************************************************
* 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.cayenne.project;
import java.util.Arrays;
/**
* Immutable holder of a selection path within a Cayenne project. Mostly used
* by various tools (CayenneModeler comes to mind) to navigate Cayenne
* projects. Contains a number of convenience methods to access path elements.
*
*
* For instance, given a path Project -> DataMap -> ObjEntity -> ObjAttribute
,
* getObject
will return ObjAttribute, getObjectParent
-
* ObjEntity, getRoot
- Project.
*
*
* @author Andrei Adamchik
*/
public class ProjectPath {
public static final Object[] EMPTY_PATH = new Object[0];
protected Object[] path;
public ProjectPath() {
path = EMPTY_PATH;
}
/**
* Constructor for ProjectPath.
*/
public ProjectPath(Object object) {
path = new Object[] { object };
}
/**
* Constructor for ProjectPath.
*/
public ProjectPath(Object[] path) {
this.path = (path != null) ? path : EMPTY_PATH;
}
public Object[] getPath() {
return path;
}
public boolean isEmpty() {
return path == null || path.length == 0;
}
/**
* Scans path, looking for the first element that is an instanceof aClass
.
*/
public Object firstInstanceOf(Class aClass) {
for (int i = 0; i < path.length; i++) {
if (path[i] != null && aClass.isAssignableFrom(path[i].getClass())) {
return path[i];
}
}
return null;
}
/**
* Returns an instance of the path, expanding this one by appending an
* object at the end.
*/
public ProjectPath appendToPath(Object object) {
if (object != null) {
Object[] newPath = new Object[path.length + 1];
if (path.length > 0) {
System.arraycopy(path, 0, newPath, 0, path.length);
}
newPath[path.length] = object;
return new ProjectPath(newPath);
}
else {
return this;
}
}
/**
*
* @since 1.1
*/
public ProjectPath subpathWithSize(int subpathSize) {
if (subpathSize <= 0) {
return new ProjectPath();
}
else if(subpathSize == path.length) {
return this;
}
if (subpathSize > path.length) {
throw new ArrayIndexOutOfBoundsException(
"Subpath is longer than this path "
+ subpathSize
+ " components. Path size: "
+ path.length);
}
Object[] newPath = new Object[subpathSize];
System.arraycopy(path, 0, newPath, 0, subpathSize);
return new ProjectPath(newPath);
}
/**
* Returns a subpath to the first occurance of an object.
*
* @since 1.1
*/
public ProjectPath subpathOfObject(Object object) {
for (int i = 0; i < path.length; i++) {
if (path[i] == object) {
// strip remaining objects
return subpathWithSize(i + 1);
}
}
return null;
}
/**
* Returns the root or starting object of the path.
*/
public Object getRoot() {
if (path.length == 0) {
return null;
}
return path[0];
}
/**
* Returns the last object in the path.
*/
public Object getObject() {
if (path.length == 0) {
return null;
}
// return last object
return path[path.length - 1];
}
/**
* Returns an object corresponding to the parent node of the node
* represented by the path. This is the object next to last object in the
* path.
*/
public Object getObjectParent() {
if (path.length == 0) {
return null;
}
// return next to last object
return (path.length > 1) ? path[path.length - 2] : null;
}
public String toString() {
StringBuffer buf = new StringBuffer();
buf.append("[ProjectPath: ");
for (int i = 0; i < path.length; i++) {
if (i > 0) {
buf.append(", ");
}
String token = (path[i] != null) ? path[i].getClass().getName() : "";
buf.append(token);
}
buf.append("]");
return buf.toString();
}
public boolean equals(Object object) {
if (object == this) {
return true;
}
if (!(object instanceof ProjectPath)) {
return false;
}
ProjectPath otherPath = (ProjectPath) object;
return Arrays.equals(getPath(), otherPath.getPath());
}
}
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