/*******************************************************************************
* Copyright (c) 2004, 2008 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.core.dom;
/**
* Descriptor for a child property of an AST node. A child property is one whose value is an
* {@link ASTNode}.
*
* @see org.eclipse.jdt.core.dom.ASTNode#getStructuralProperty(StructuralPropertyDescriptor)
* @see org.eclipse.jdt.core.dom.ASTNode#setStructuralProperty(StructuralPropertyDescriptor, Object)
* @since 3.0
* @noinstantiate This class is not intended to be instantiated by clients.
*/
public final class ChildPropertyDescriptor extends StructuralPropertyDescriptor {
/**
* Child type. For example, for a node type like CompilationUnit, the "package" property is
* PackageDeclaration.class
*/
private final Class childClass;
/**
* Indicates whether the child is mandatory. A child property is allowed to be <code>null</code>
* only if it is not mandatory.
*/
private final boolean mandatory;
/**
* Indicates whether a cycle is possible. Field is private, but marked package-visible for fast
* access from ASTNode.
*/
final boolean cycleRisk;
/**
* Creates a new child property descriptor with the given property id. Note that this
* constructor is declared package-private so that property descriptors can only be created by
* the AST implementation.
*
* @param nodeClass concrete AST node type that owns this property
* @param propertyId the property id
* @param childType the child type of this property
* @param mandatory <code>true</code> if the property is mandatory, and <code>false</code> if it
* is may be <code>null</code>
* @param cycleRisk <code>true</code> if this property is at risk of cycles, and
* <code>false</code> if there is no worry about cycles
*/
ChildPropertyDescriptor(Class nodeClass, String propertyId, Class childType, boolean mandatory, boolean cycleRisk) {
super(nodeClass, propertyId);
if (childType == null || !ASTNode.class.isAssignableFrom(childType)) {
throw new IllegalArgumentException();
}
this.childClass= childType;
this.mandatory= mandatory;
this.cycleRisk= cycleRisk;
}
/**
* Returns the child type of this property.
* <p>
* For example, for a node type like CompilationUnit, the "package" property returns
* <code>PackageDeclaration.class</code>.
* </p>
*
* @return the child type of the property
*/
public final Class getChildType() {
return this.childClass;
}
/**
* Returns whether this property is mandatory. A property value is not allowed to be
* <code>null</code> if it is mandatory.
*
* @return <code>true</code> if the property is mandatory, and <code>false</code> if it is may
* be <code>null</code>
*/
public final boolean isMandatory() {
return this.mandatory;
}
/**
* Returns whether this property is vulnerable to cycles.
* <p>
* A property is vulnerable to cycles if a node of the owning type (that is, the type that owns
* this property) could legally appear in the AST subtree below this property. For example, the
* body property of a {@link MethodDeclaration} node admits a body which might include statement
* that embeds another {@link MethodDeclaration} node. On the other hand, the name property of a
* MethodDeclaration node admits only names, and thereby excludes another MethodDeclaration
* node.
* </p>
*
* @return <code>true</code> if cycles are possible, and <code>false</code> if cycles are
* impossible
*/
public final boolean cycleRisk() {
return this.cycleRisk;
}
}