Copyright (c) 2015, 2016 Google, Inc and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
  Stefan Xenos (Google) - Initial implementation
/*******************************************************************************
 * Copyright (c) 2015, 2016 Google, Inc and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *   Stefan Xenos (Google) - Initial implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core.nd.java;

import java.util.List;
import java.util.function.Supplier;

import org.eclipse.jdt.internal.core.nd.DatabaseRef;
import org.eclipse.jdt.internal.core.nd.IReader;
import org.eclipse.jdt.internal.core.nd.Nd;

Holds a reference to an NdType that can be retained while releasing and reacquiring a read lock.
/**
 * Holds a reference to an NdType that can be retained while releasing and reacquiring a read lock.
 */
public final class TypeRef implements Supplier<NdType> {
	final DatabaseRef<NdType> ref;
	final char[] fileName;
	final char[] fieldDescriptor;
	final TypeSupplier typeSupplier = new TypeSupplier();
	private final class TypeSupplier implements Supplier<NdType> {
		public TypeSupplier() {
		}

		@Override
		public NdType get() {
			NdTypeId typeId = JavaIndex.getIndex(TypeRef.this.ref.getNd()).findType(TypeRef.this.fieldDescriptor);

			if (typeId == null) {
				return null;
			}

			List<NdType> implementations = typeId.getTypes();
			for (NdType next : implementations) {
				NdResourceFile nextResourceFile = next.getResourceFile();
				if (nextResourceFile.getLocation().compare(TypeRef.this.fileName, false) == 0) {
					if (nextResourceFile.isDoneIndexing()) {
						return next;
					}
				}
			}
			return null;
		}
	}

	private TypeRef(NdType type) {
		super();
		this.fieldDescriptor = type.getTypeId().getRawType().getFieldDescriptor().getChars();
		this.fileName = type.getResourceFile().getLocation().getChars();
		this.ref = new DatabaseRef<NdType>(type.getNd(), this.typeSupplier, type);
	}

	private TypeRef(Nd nd, char[] resourcePath, char[] fieldDescriptor) {
		super();
		this.fieldDescriptor = fieldDescriptor;
		this.fileName = resourcePath;
		this.ref = new DatabaseRef<NdType>(nd, this.typeSupplier);
	}

	public char[] getFieldDescriptor() {
		return this.fieldDescriptor;
	}

	public char[] getFileName() {
		return this.fileName;
	}

	
Creates a DatabaseRef to the given NdType. /**
	 * Creates a {@link DatabaseRef} to the given {@link NdType}.
	 */
	public static TypeRef create(NdType type) {
		return new TypeRef(type);
	}

	
Creates a DatabaseRef to the NdType with the given resource path and field descriptor. /**
	 * Creates a {@link DatabaseRef} to the {@link NdType} with the given resource path and field descriptor.
	 */
	public static TypeRef create(Nd nd, char[] resourcePath, char[] fieldDescriptor) {
		return new TypeRef(nd, resourcePath, fieldDescriptor);
	}

	public IReader lock() {
		return this.ref.lock();
	}

	@Override
	public NdType get() {
		return this.ref.get();
	}
}