/*
 * Copyright (c) 2009, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package jdk.vm.ci.hotspot;

import java.lang.invoke.CallSite;
import java.util.Objects;

import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.ResolvedJavaType;
import jdk.vm.ci.meta.VMConstant;

/**
 * Represents a constant non-{@code null} object reference, within the compiler and across the
 * compiler/runtime interface.
 */
public interface HotSpotObjectConstant extends JavaConstant, HotSpotConstant, VMConstant {

    JavaConstant compress();

    JavaConstant uncompress();

    /**
     * Gets the resolved Java type of the object represented by this constant.
     */
    HotSpotResolvedObjectType getType();

    /**
     * Gets the result of {@link Class#getClassLoader()} for the {@link Class} object represented by
     * this constant.
     *
     * @return {@code null} if this constant does not represent a {@link Class} object
     */
    JavaConstant getClassLoader();

    /**
     * Gets the {@linkplain System#identityHashCode(Object) identity} has code for the object
     * represented by this constant.
     */
    int getIdentityHashCode();

    /**
     * Gets the result of {@link Class#getComponentType()} for the {@link Class} object represented
     * by this constant.
     *
     * @return {@code null} if this constant does not represent a {@link Class} object
     */
    JavaConstant getComponentType();

    /**
     * Gets the result of {@link Class#getSuperclass()} for the {@link Class} object represented by
     * this constant.
     *
     * @return {@code null} if this constant does not represent a {@link Class} object
     */
    JavaConstant getSuperclass();

    /**
     * Gets the result of {@link CallSite#getTarget()} for the {@link CallSite} object represented
     * by this constant.
     *
     * @param assumptions used to register an assumption that the {@link CallSite}'s target does not
     *            change
     * @return {@code null} if this constant does not represent a {@link CallSite} object
     */
    JavaConstant getCallSiteTarget(Assumptions assumptions);

    /**
     * Determines if this constant represents an {@linkplain String#intern() interned} string.
     */
    boolean isInternedString();

    /**
     * Gets the object represented by this constant represents if it is of a given type.
     *
     * @param type the expected type of the object represented by this constant. If the object is
     *            required to be of this type, then wrap the call to this method in
     *            {@link Objects#requireNonNull(Object)}.
     * @return the object value represented by this constant if it is an
     *         {@link ResolvedJavaType#isInstance(JavaConstant) instance of} {@code type} otherwise
     *         {@code null}
     */
    <T> T asObject(Class<T> type);

    /**
     * Gets the object represented by this constant represents if it is of a given type.
     *
     * @param type the expected type of the object represented by this constant. If the object is
     *            required to be of this type, then wrap the call to this method in
     *            {@link Objects#requireNonNull(Object)}.
     * @return the object value represented by this constant if it is an
     *         {@link ResolvedJavaType#isInstance(JavaConstant) instance of} {@code type} otherwise
     *         {@code null}
     */
    Object asObject(ResolvedJavaType type);
}