/*******************************************************************************
* Copyright (c) 2009 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
* Zend Technologies
*******************************************************************************/
package org.eclipse.php.core.ast.nodes;
/**
* Descriptor for a child list property of an AST node. A child list property is
* one whose value is a list of {@link ASTNode}.
*
* @see org.eclipse.jdt.core.dom.ASTNode#getStructuralProperty(StructuralPropertyDescriptor)
* @since 3.0
*/
public final class ChildListPropertyDescriptor extends StructuralPropertyDescriptor {
/**
* Element type. For example, for a node type like CompilationUnit, the
* "imports" property is ImportDeclaration.class.
* <p>
* Field is private, but marked package-visible for fast access from
* ASTNode.
* </p>
*/
final Class elementType;
/**
* Indicates whether a cycle is possible.
* <p>
* Field is private, but marked package-visible for fast access from
* ASTNode.
* </p>
*/
final boolean cycleRisk;
/**
* Creates a new child list 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 elementType
* the element type of this property
* @param cycleRisk
* <code>true</code> if this property is at risk of cycles, and
* <code>false</code> if there is no worry about cycles
*/
ChildListPropertyDescriptor(Class nodeClass, String propertyId, Class elementType, boolean cycleRisk) {
super(nodeClass, propertyId);
if (elementType == null) {
throw new IllegalArgumentException();
}
this.elementType = elementType;
this.cycleRisk = cycleRisk;
}
/**
* Returns the element type of this list property.
* <p>
* For example, for a node type like CompilationUnit, the "imports" property
* returns <code>ImportDeclaration.class</code>.
* </p>
*
* @return the element type of the property
*/
public final Class getElementType() {
return this.elementType;
}
/**
* 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;
}
}