/*
 * Copyright (c) 1994, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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 sun.tools.java;

import sun.tools.tree.Node;
import sun.tools.tree.Vset;
import sun.tools.tree.Expression;
import sun.tools.tree.Statement;
import sun.tools.tree.Context;
import sun.tools.asm.Assembler;
import java.io.PrintStream;
import java.util.Vector;
import java.util.Map;
import java.util.HashMap;

This class defines a member of a Java class:
a variable, a method, or an inner class.
WARNING: The contents of this source file are not part of any
supported API.  Code that depends on them does so at its own risk:
they are subject to change or removal without notice.
/**
 * This class defines a member of a Java class:
 * a variable, a method, or an inner class.
 *
 * WARNING: The contents of this source file are not part of any
 * supported API.  Code that depends on them does so at its own risk:
 * they are subject to change or removal without notice.
 */
@SuppressWarnings("deprecation")
public
class MemberDefinition implements Constants {
    protected long where;
    protected int modifiers;
    protected Type type;
    protected String documentation;
    protected IdentifierToken expIds[];
    protected ClassDeclaration exp[];
    protected Node value;
    protected ClassDefinition clazz;
    protected Identifier name;
    protected ClassDefinition innerClass;
    protected MemberDefinition nextMember;
    protected MemberDefinition nextMatch;
    protected MemberDefinition accessPeer;
    protected boolean superAccessMethod;

    
Constructor
/**
     * Constructor
     */
    public MemberDefinition(long where, ClassDefinition clazz, int modifiers,
                            Type type, Identifier name,
                            IdentifierToken expIds[], Node value) {
        if (expIds == null) {
            expIds = new IdentifierToken[0];
        }
        this.where = where;
        this.clazz = clazz;
        this.modifiers = modifiers;
        this.type = type;
        this.name = name;
        this.expIds = expIds;
        this.value = value;
    }

    
Constructor for an inner class.
Inner classes are represented as fields right along with
variables and methods for simplicity of data structure,
and to reflect properly the textual declaration order.

This constructor calls the generic constructor for this
class, extracting all necessary values from the innerClass.
/**
     * Constructor for an inner class.
     * Inner classes are represented as fields right along with
     * variables and methods for simplicity of data structure,
     * and to reflect properly the textual declaration order.
     * <p>
     * This constructor calls the generic constructor for this
     * class, extracting all necessary values from the innerClass.
     */
    public MemberDefinition(ClassDefinition innerClass) {
        this(innerClass.getWhere(),
             innerClass.getOuterClass(),
             innerClass.getModifiers(),
             innerClass.getType(),
             innerClass.getName().getFlatName().getName(),
             null, null);
        this.innerClass = innerClass;
    }

    
A cache of previously created proxy members.  Used to ensure
uniqueness of proxy objects.  See the makeProxyMember method
defined below.
/**
     * A cache of previously created proxy members.  Used to ensure
     * uniqueness of proxy objects.  See the makeProxyMember method
     * defined below.
     */
    static private Map<String,MemberDefinition> proxyCache;

    
Create a member which is externally the same as `field' but
is defined in class `classDef'.  This is used by code
in sun.tools.tree.(MethodExpression,FieldExpression) as
part of the fix for bug 4135692.
Proxy members should not be added, ala addMember(), to classes.
They are merely "stand-ins" to produce modified MethodRef
constant pool entries during code generation.
We keep a cache of previously created proxy members not to
save time or space, but to ensure uniqueness of the proxy
member for any (field,classDef) pair.  If these are not made
unique then we can end up generating duplicate MethodRef
constant pool entries during code generation.
/**
     * Create a member which is externally the same as `field' but
     * is defined in class `classDef'.  This is used by code
     * in sun.tools.tree.(MethodExpression,FieldExpression) as
     * part of the fix for bug 4135692.
     *
     * Proxy members should not be added, ala addMember(), to classes.
     * They are merely "stand-ins" to produce modified MethodRef
     * constant pool entries during code generation.
     *
     * We keep a cache of previously created proxy members not to
     * save time or space, but to ensure uniqueness of the proxy
     * member for any (field,classDef) pair.  If these are not made
     * unique then we can end up generating duplicate MethodRef
     * constant pool entries during code generation.
     */
    public static MemberDefinition makeProxyMember(MemberDefinition field,
                                                   ClassDefinition classDef,
                                                   Environment env) {

        if (proxyCache == null) {
            proxyCache = new HashMap<>();
        }

        String key = field.toString() + "@" + classDef.toString();
        // System.out.println("Key is : " + key);
        MemberDefinition proxy = proxyCache.get(key);

        if (proxy != null)
            return proxy;

        proxy = new MemberDefinition(field.getWhere(), classDef,
                                     field.getModifiers(), field.getType(),
                                     field.getName(), field.getExceptionIds(),
                                     null);
        proxy.exp = field.getExceptions(env);
        proxyCache.put(key, proxy);

        return proxy;
    }

    
Get the position in the input
/**
     * Get the position in the input
     */
    public final long getWhere() {
        return where;
    }

    
Get the class declaration
/**
     * Get the class declaration
     */
    public final ClassDeclaration getClassDeclaration() {
        return clazz.getClassDeclaration();
    }

    
A stub.  Subclasses can do more checking.
/**
     * A stub.  Subclasses can do more checking.
     */
    public void resolveTypeStructure(Environment env) {
    }

    
Get the class declaration in which the field is actually defined
/**
     * Get the class declaration in which the field is actually defined
     */
    public ClassDeclaration getDefiningClassDeclaration() {
        return getClassDeclaration();
    }

    
Get the class definition
/**
     * Get the class definition
     */
    public final ClassDefinition getClassDefinition() {
        return clazz;
    }

    
Get the field's top-level enclosing class
/**
     * Get the field's top-level enclosing class
     */
    public final ClassDefinition getTopClass() {
        return clazz.getTopClass();
    }

    
Get the field's modifiers
/**
     * Get the field's modifiers
     */
    public final int getModifiers() {
        return modifiers;
    }
    public final void subModifiers(int mod) {
        modifiers &= ~mod;
    }
    public final void addModifiers(int mod) {
        modifiers |= mod;
    }

    
Get the field's type
/**
     * Get the field's type
     */
    public final Type getType() {
        return type;
    }

    
Get the field's name
/**
     * Get the field's name
     */
    public final Identifier getName() {
        return name;
    }

    
Get arguments (a vector of LocalMember)
/**
     * Get arguments (a vector of LocalMember)
     */
    public Vector<MemberDefinition> getArguments() {
        return isMethod() ? new Vector<>() : null;
    }

    
Get the exceptions that are thrown by this method.
/**
     * Get the exceptions that are thrown by this method.
     */
    public ClassDeclaration[] getExceptions(Environment env) {
        if (expIds != null && exp == null) {
            if (expIds.length == 0)
                exp = new ClassDeclaration[0];
            else
                // we should have translated this already!
                throw new CompilerError("getExceptions "+this);
        }
        return exp;
    }

    public final IdentifierToken[] getExceptionIds() {
        return expIds;
    }

    
Get an inner class.
/**
     * Get an inner class.
     */
    public ClassDefinition getInnerClass() {
        return innerClass;
    }

    
Is this a synthetic field which holds a copy of,
or reference to, a local variable or enclosing instance?
/**
     * Is this a synthetic field which holds a copy of,
     * or reference to, a local variable or enclosing instance?
     */
    public boolean isUplevelValue() {
        if (!isSynthetic() || !isVariable() || isStatic()) {
            return false;
        }
        String name = this.name.toString();
        return name.startsWith(prefixVal)
            || name.startsWith(prefixLoc)
            || name.startsWith(prefixThis);
    }

    public boolean isAccessMethod() {
        // This no longer works, because access methods
        // for constructors do not use the standard naming
        // scheme.
        //    return isSynthetic() && isMethod()
        //        && name.toString().startsWith(prefixAccess);
        // Assume that a method is an access method if it has
        // an access peer.  NOTE: An access method will not be
        // recognized as such until 'setAccessMethodTarget' has
        // been called on it.
        return isSynthetic() && isMethod() && (accessPeer != null);
    }

    
Is this a synthetic method which provides access to a
visible private member?
/**
     * Is this a synthetic method which provides access to a
     * visible private member?
     */
    public MemberDefinition getAccessMethodTarget() {
        if (isAccessMethod()) {
            for (MemberDefinition f = accessPeer; f != null; f = f.accessPeer) {
                // perhaps skip over another access for the same field
                if (!f.isAccessMethod()) {
                    return f;
                }
            }
        }
        return null;
    }


    public void setAccessMethodTarget(MemberDefinition target) {
        if (getAccessMethodTarget() != target) {
            /*-------------------*
            if (!isAccessMethod() || accessPeer != null ||
                    target.accessPeer != null) {
                throw new CompilerError("accessPeer");
            }
            *-------------------*/
            if (accessPeer != null || target.accessPeer != null) {
                throw new CompilerError("accessPeer");
            }
            accessPeer = target;
        }
    }

    
If this method is a getter for a private field, return the setter.
/**
     * If this method is a getter for a private field, return the setter.
     */
    public MemberDefinition getAccessUpdateMember() {
        if (isAccessMethod()) {
            for (MemberDefinition f = accessPeer; f != null; f = f.accessPeer) {
                if (f.isAccessMethod()) {
                    return f;
                }
            }
        }
        return null;
    }

    public void setAccessUpdateMember(MemberDefinition updater) {
        if (getAccessUpdateMember() != updater) {
            if (!isAccessMethod() ||
                    updater.getAccessMethodTarget() != getAccessMethodTarget()) {
                throw new CompilerError("accessPeer");
            }
            updater.accessPeer = accessPeer;
            accessPeer = updater;
        }
    }

    
Is this an access method for a field selection or method call
of the form '...super.foo' or '...super.foo()'?
/**
     * Is this an access method for a field selection or method call
     * of the form '...super.foo' or '...super.foo()'?
     */
    public final boolean isSuperAccessMethod() {
        return superAccessMethod;
    }

    
Mark this member as an access method for a field selection
or method call via the 'super' keyword.
/**
     * Mark this member as an access method for a field selection
     * or method call via the 'super' keyword.
     */
    public final void setIsSuperAccessMethod(boolean b) {
        superAccessMethod = b;
    }

    
Tell if this is a final variable without an initializer.
Such variables are subject to definite single assignment.
/**
     * Tell if this is a final variable without an initializer.
     * Such variables are subject to definite single assignment.
     */
    public final boolean isBlankFinal() {
        return isFinal() && !isSynthetic() && getValue() == null;
    }

    public boolean isNeverNull() {
        if (isUplevelValue()) {
            // loc$x and this$C are never null
            return !name.toString().startsWith(prefixVal);
        }
        return false;
    }

    
Get the field's final value (may return null)
/**
     * Get the field's final value (may return null)
     */
    public Node getValue(Environment env) throws ClassNotFound {
        return value;
    }
    public final Node getValue() {
        return value;
    }
    public final void setValue(Node value) {
        this.value = value;
    }
    public Object getInitialValue() {
        return null;
    }

    
Get the next field or the next match
/**
     * Get the next field or the next match
     */
    public final MemberDefinition getNextMember() {
        return nextMember;
    }
    public final MemberDefinition getNextMatch() {
        return nextMatch;
    }

    
Get the field's documentation
/**
     * Get the field's documentation
     */
    public String getDocumentation() {
        return documentation;
    }

    
Request a check of the field definition.
/**
     * Request a check of the field definition.
     */
    public void check(Environment env) throws ClassNotFound {
    }

    
Really check the field definition.
/**
     * Really check the field definition.
     */
    public Vset check(Environment env, Context ctx, Vset vset) throws ClassNotFound {
        return vset;
    }

    
Generate code
/**
     * Generate code
     */
    public void code(Environment env, Assembler asm) throws ClassNotFound {
        throw new CompilerError("code");
    }
    public void codeInit(Environment env, Context ctx, Assembler asm) throws ClassNotFound {
        throw new CompilerError("codeInit");
    }

    
Tells whether to report a deprecation error for this field.
/**
     * Tells whether to report a deprecation error for this field.
     */
    public boolean reportDeprecated(Environment env) {
        return (isDeprecated() || clazz.reportDeprecated(env));
    }

    
Check if a field can reach another field (only considers
forward references, not the access modifiers).
/**
     * Check if a field can reach another field (only considers
     * forward references, not the access modifiers).
     */
    public final boolean canReach(Environment env, MemberDefinition f) {
        if (f.isLocal() || !f.isVariable() || !(isVariable() || isInitializer()))
            return true;
        if ((getClassDeclaration().equals(f.getClassDeclaration())) &&
            (isStatic() == f.isStatic())) {
            // They are located in the same class, and are either both
            // static or both non-static.  Check the initialization order.
            while (((f = f.getNextMember()) != null) && (f != this));
            return f != null;
        }
        return true;
    }

    //-----------------------------------------------------------------
    // The code in this section is intended to test certain kinds of
    // compatibility between methods.  There are two kinds of compatibility
    // that the compiler may need to test.  The first is whether one
    // method can legally override another.  The second is whether two
    // method definitions can legally coexist.  We use the word `meet'
    // to mean the intersection of two legally coexisting methods.
    // For more information on these kinds of compatibility, see the
    // comments/code for checkOverride() and checkMeet() below.

    
Constants used by getAccessLevel() to represent the access
modifiers as numbers.
/**
     * Constants used by getAccessLevel() to represent the access
     * modifiers as numbers.
     */
    static final int PUBLIC_ACCESS = 1;
    static final int PROTECTED_ACCESS = 2;
    static final int PACKAGE_ACCESS = 3;
    static final int PRIVATE_ACCESS = 4;

    
Return the access modifier of this member as a number.  The idea
is that this number may be used to check properties like "the
access modifier of x is more restrictive than the access
modifier of y" with a simple inequality test:
"x.getAccessLevel() > y.getAccessLevel.
This is an internal utility method.
/**
     * Return the access modifier of this member as a number.  The idea
     * is that this number may be used to check properties like "the
     * access modifier of x is more restrictive than the access
     * modifier of y" with a simple inequality test:
     * "x.getAccessLevel() > y.getAccessLevel.
     *
     * This is an internal utility method.
     */
    private int getAccessLevel() {
        // Could just compute this once instead of recomputing.
        // Check to see if this is worth it.
        if (isPublic()) {
            return PUBLIC_ACCESS;
        } else if (isProtected()) {
            return PROTECTED_ACCESS;
        } else if (isPackagePrivate()) {
            return PACKAGE_ACCESS;
        } else if (isPrivate()) {
            return PRIVATE_ACCESS;
        } else {
            throw new CompilerError("getAccessLevel()");
        }
    }

    
Munge our error message to report whether the override conflict
came from an inherited method or a declared method.
/**
     * Munge our error message to report whether the override conflict
     * came from an inherited method or a declared method.
     */
    private void reportError(Environment env, String errorString,
                             ClassDeclaration clazz,
                             MemberDefinition method) {

        if (clazz == null) {
            // For example:
            // "Instance method BLAH inherited from CLASSBLAH1 cannot be
            //  overridden by the static method declared in CLASSBLAH2."
            env.error(getWhere(), errorString,
                      this, getClassDeclaration(),
                      method.getClassDeclaration());
        } else {
            // For example:
            // "In CLASSBLAH1, instance method BLAH inherited from CLASSBLAH2
            //  cannot be overridden by the static method inherited from
            //  CLASSBLAH3."
            env.error(clazz.getClassDefinition().getWhere(),
                      //"inherit." + errorString,
                      errorString,
                      //clazz,
                      this, getClassDeclaration(),
                      method.getClassDeclaration());
        }
    }

    
Convenience method to see if two methods return the same type
/**
     * Convenience method to see if two methods return the same type
     */
    public boolean sameReturnType(MemberDefinition method) {
        // Make sure both are methods.
        if (!isMethod() || !method.isMethod()) {
            throw new CompilerError("sameReturnType: not method");
        }

        Type myReturnType = getType().getReturnType();
        Type yourReturnType = method.getType().getReturnType();

        return (myReturnType == yourReturnType);
    }

    
Check to see if `this' can override/hide `method'.  Caller is
responsible for verifying that `method' has the same signature
as `this'.  Caller is also responsible for verifying that
`method' is visible to the class where this override is occurring.
This method is called for the case when class B extends A and both
A and B define some method.
      A - void foo() throws e1
      |
      |
      B - void foo() throws e2

/**
     * Check to see if `this' can override/hide `method'.  Caller is
     * responsible for verifying that `method' has the same signature
     * as `this'.  Caller is also responsible for verifying that
     * `method' is visible to the class where this override is occurring.
     * This method is called for the case when class B extends A and both
     * A and B define some method.
     * <pre>
     *       A - void foo() throws e1
     *       |
     *       |
     *       B - void foo() throws e2
     * </pre>
     */
    public boolean checkOverride(Environment env, MemberDefinition method) {
        return checkOverride(env, method, null);
    }

    
Checks whether `this' can override `method'.  It `clazz' is
null, it reports the errors in the class where `this' is
declared.  If `clazz' is not null, it reports the error in `clazz'.
/**
     * Checks whether `this' can override `method'.  It `clazz' is
     * null, it reports the errors in the class where `this' is
     * declared.  If `clazz' is not null, it reports the error in `clazz'.
     */
    private boolean checkOverride(Environment env,
                                  MemberDefinition method,
                                  ClassDeclaration clazz) {
        // This section of code is largely based on section 8.4.6.3
        // of the JLS.

        boolean success = true;

        // Sanity
        if (!isMethod()) {
            throw new CompilerError("checkOverride(), expected method");
        }

        // Suppress checks for synthetic methods, as the compiler presumably
        // knows what it is doing, e.g., access methods.
        if (isSynthetic()) {
            // Sanity check: We generally do not intend for one synthetic
            // method to override another, though hiding of static members
            // is expected.  This check may need to be changed if new uses
            // of synthetic methods are devised.
            //
            // Query: this code was copied from elsewhere.  What
            // exactly is the role of the !isStatic() in the test?
            if (method.isFinal() ||
                (!method.isConstructor() &&
                 !method.isStatic() && !isStatic())) {
                ////////////////////////////////////////////////////////////
                // NMG 2003-01-28 removed the following test because it is
                // invalidated by bridge methods inserted by the "generic"
                // (1.5) Java compiler.  In 1.5, this code is used,
                // indirectly, by rmic
                ////////////////////////////////////////////////////////////
                // throw new CompilerError("checkOverride() synthetic");
                ////////////////////////////////////////////////////////////
            }

            // We trust the compiler.  (Ha!)  We're done checking.
            return true;
        }

        // Our caller should have verified that the method had the
        // same signature.
        if (getName() != method.getName() ||
            !getType().equalArguments(method.getType())) {

            throw new CompilerError("checkOverride(), signature mismatch");
        }

        // It is forbidden to `override' a static method with an instance
        // method.
        if (method.isStatic() && !isStatic()) {
            reportError(env, "override.static.with.instance", clazz, method);
            success = false;
        }

        // It is forbidden to `hide' an instance method with a static
        // method.
        if (!method.isStatic() && isStatic()) {
            reportError(env, "hide.instance.with.static", clazz, method);
            success = false;
        }

        // We cannot override a final method.
        if (method.isFinal()) {
            reportError(env, "override.final.method", clazz, method);
            success = false;
        }

        // Give a warning when we override a deprecated method with
        // a non-deprecated one.
        //
        // We bend over backwards to suppress this warning if
        // the `method' has not been already compiled or
        // `this' has been already compiled.
        if (method.reportDeprecated(env) && !isDeprecated()
               && this instanceof sun.tools.javac.SourceMember) {
            reportError(env, "warn.override.is.deprecated",
                        clazz, method);
        }

        // Visibility may not be more restrictive
        if (getAccessLevel() > method.getAccessLevel()) {
            reportError(env, "override.more.restrictive", clazz, method);
            success = false;
        }

        // Return type equality
        if (!sameReturnType(method)) {
            ////////////////////////////////////////////////////////////
            // PCJ 2003-07-30 removed the following error because it is
            // invalidated by the covariant return type feature of the
            // 1.5 compiler.  The resulting check is now much looser
            // than the actual 1.5 language spec, but that should be OK
            // because this code is only still used by rmic.  See 4892308.
            ////////////////////////////////////////////////////////////
            // reportError(env, "override.different.return", clazz, method);
            // success = false;
            ////////////////////////////////////////////////////////////
        }

        // Exception agreeement
        if (!exceptionsFit(env, method)) {
            reportError(env, "override.incompatible.exceptions",
                        clazz, method);
            success = false;
        }

        return success;
    }

    
Check to see if two method definitions are compatible, that is
do they have a `meet'.  The meet of two methods is essentially
and `intersection' of
two methods.  This method is called when some class C inherits
declarations for some method foo from two parents (superclass,
interfaces) but it does not, itself, have a declaration of foo.
Caller is responsible for making sure that both methods are
indeed visible in clazz.
    A - void foo() throws e1
     \
      \     B void foo() throws e2
       \   /
        \ /
         C

/**
     * Check to see if two method definitions are compatible, that is
     * do they have a `meet'.  The meet of two methods is essentially
     * and `intersection' of
     * two methods.  This method is called when some class C inherits
     * declarations for some method foo from two parents (superclass,
     * interfaces) but it does not, itself, have a declaration of foo.
     * Caller is responsible for making sure that both methods are
     * indeed visible in clazz.
     * <pre>
     *     A - void foo() throws e1
     *      \
     *       \     B void foo() throws e2
     *        \   /
     *         \ /
     *          C
     * </pre>
     */
    public boolean checkMeet(Environment env,
                             MemberDefinition method,
                             ClassDeclaration clazz) {
        // This section of code is largely based on Section 8.4.6
        // and 9.4.1 of the JLS.

        // Sanity
        if (!isMethod()) {
            throw new CompilerError("checkMeet(), expected method");
        }

        // Check for both non-abstract.
        if (!isAbstract() && !method.isAbstract()) {
            throw new CompilerError("checkMeet(), no abstract method");
        }

        // If either method is non-abstract, then we need to check that
        // the abstract method can be properly overridden.  We call
        // the checkOverride method to check this and generate any errors.
        // This test must follow the previous test.
        else if (!isAbstract()) {
            return checkOverride(env, method, clazz);
        } else if (!method.isAbstract()) {
            return method.checkOverride(env, this, clazz);
        }

        // Both methods are abstract.

        // Our caller should have verified that the method has the
        // same signature.
        if (getName() != method.getName() ||
            !getType().equalArguments(method.getType())) {

            throw new CompilerError("checkMeet(), signature mismatch");
        }

        // Check for return type equality
        if (!sameReturnType(method)) {
            // More args?
            env.error(clazz.getClassDefinition().getWhere(),
                      "meet.different.return",
                      this, this.getClassDeclaration(),
                      method.getClassDeclaration());
            return false;
        }

        // We don't have to check visibility -- there always
        // potentially exists a meet.  Similarly with exceptions.

        // There does exist a meet.
        return true;
    }

    
This method is meant to be used to determine if one of two inherited
methods could override the other.  Unlike checkOverride(), failure
is not an error.  This method is only meant to be called after
checkMeet() has succeeded on the two methods.
If you call couldOverride() without doing a checkMeet() first, then
you are on your own.
/**
     * This method is meant to be used to determine if one of two inherited
     * methods could override the other.  Unlike checkOverride(), failure
     * is not an error.  This method is only meant to be called after
     * checkMeet() has succeeded on the two methods.
     *
     * If you call couldOverride() without doing a checkMeet() first, then
     * you are on your own.
     */
    public boolean couldOverride(Environment env,
                                 MemberDefinition method) {

        // Sanity
        if (!isMethod()) {
            throw new CompilerError("coulcOverride(), expected method");
        }

        // couldOverride() is only called with `this' and `method' both
        // being inherited methods.  Neither of them is defined in the
        // class which we are currently working on.  Even though an
        // abstract method defined *in* a class can override a non-abstract
        // method defined in a superclass, an abstract method inherited
        // from an interface *never* can override a non-abstract method.
        // This comment may sound odd, but that's the way inheritance is.
        // The following check makes sure we aren't trying to override
        // an inherited non-abstract definition with an abstract definition
        // from an interface.
        if (!method.isAbstract()) {
            return false;
        }

        // Visibility should be less restrictive
        if (getAccessLevel() > method.getAccessLevel()) {
            return false;
        }

        // Exceptions
        if (!exceptionsFit(env, method)) {
            return false;
        }

        // Potentially some deprecation warnings could be given here
        // when we merge two abstract methods, one of which is deprecated.
        // This is not currently reported.

        return true;
    }

    
Check to see if the exceptions of `this' fit within the
exceptions of `method'.
/**
     * Check to see if the exceptions of `this' fit within the
     * exceptions of `method'.
     */
    private boolean exceptionsFit(Environment env,
                                  MemberDefinition method) {
        ClassDeclaration e1[] = getExceptions(env);        // my exceptions
        ClassDeclaration e2[] = method.getExceptions(env); // parent's

        // This code is taken nearly verbatim from the old implementation
        // of checkOverride() in SourceClass.
    outer:
        for (int i = 0 ; i < e1.length ; i++) {
            try {
                ClassDefinition c1 = e1[i].getClassDefinition(env);
                for (int j = 0 ; j < e2.length ; j++) {
                    if (c1.subClassOf(env, e2[j])) {
                        continue outer;
                    }
                }
                if (c1.subClassOf(env,
                                  env.getClassDeclaration(idJavaLangError)))
                    continue outer;
                if (c1.subClassOf(env,
                                  env.getClassDeclaration(idJavaLangRuntimeException)))
                    continue outer;

                // the throws was neither something declared by a parent,
                // nor one of the ignorables.
                return false;

            } catch (ClassNotFound ee) {
                // We were unable to find one of the exceptions.
                env.error(getWhere(), "class.not.found",
                          ee.name, method.getClassDeclaration());
            }
        }

        // All of the exceptions `fit'.
        return true;
    }

    //-----------------------------------------------------------------

    
Checks
/**
     * Checks
     */
    public final boolean isPublic() {
        return (modifiers & M_PUBLIC) != 0;
    }
    public final boolean isPrivate() {
        return (modifiers & M_PRIVATE) != 0;
    }
    public final boolean isProtected() {
        return (modifiers & M_PROTECTED) != 0;
    }
    public final boolean isPackagePrivate() {
        return (modifiers & (M_PUBLIC | M_PRIVATE | M_PROTECTED)) == 0;
    }
    public final boolean isFinal() {
        return (modifiers & M_FINAL) != 0;
    }
    public final boolean isStatic() {
        return (modifiers & M_STATIC) != 0;
    }
    public final boolean isSynchronized() {
        return (modifiers & M_SYNCHRONIZED) != 0;
    }
    public final boolean isAbstract() {
        return (modifiers & M_ABSTRACT) != 0;
    }
    public final boolean isNative() {
        return (modifiers & M_NATIVE) != 0;
    }
    public final boolean isVolatile() {
        return (modifiers & M_VOLATILE) != 0;
    }
    public final boolean isTransient() {
        return (modifiers & M_TRANSIENT) != 0;
    }
    public final boolean isMethod() {
        return type.isType(TC_METHOD);
    }
    public final boolean isVariable() {
        return !type.isType(TC_METHOD) && innerClass == null;
    }
    public final boolean isSynthetic() {
        return (modifiers & M_SYNTHETIC) != 0;
    }
    public final boolean isDeprecated() {
        return (modifiers & M_DEPRECATED) != 0;
    }
    public final boolean isStrict() {
        return (modifiers & M_STRICTFP) != 0;
    }
    public final boolean isInnerClass() {
        return innerClass != null;
    }
    public final boolean isInitializer() {
        return getName().equals(idClassInit);
    }
    public final boolean isConstructor() {
        return getName().equals(idInit);
    }
    public boolean isLocal() {
        return false;
    }
    public boolean isInlineable(Environment env, boolean fromFinal) throws ClassNotFound {
        return (isStatic() || isPrivate() || isFinal() || isConstructor() || fromFinal) &&
            !(isSynchronized() || isNative());
    }

    
Check if constant:  Will it inline away to a constant?
/**
     * Check if constant:  Will it inline away to a constant?
     */
    public boolean isConstant() {
        if (isFinal() && isVariable() && value != null) {
            try {
                // If an infinite regress requeries this name,
                // deny that it is a constant.
                modifiers &= ~M_FINAL;
                return ((Expression)value).isConstant();
            } finally {
                modifiers |= M_FINAL;
            }
        }
        return false;
    }

    
toString
/**
     * toString
     */
    public String toString() {
        Identifier name = getClassDefinition().getName();
        if (isInitializer()) {
            return isStatic() ? "static {}" : "instance {}";
        } else if (isConstructor()) {
            StringBuilder sb = new StringBuilder();
            sb.append(name);
            sb.append('(');
            Type argTypes[] = getType().getArgumentTypes();
            for (int i = 0 ; i < argTypes.length ; i++) {
                if (i > 0) {
                    sb.append(',');
                }
                sb.append(argTypes[i].toString());
            }
            sb.append(')');
            return sb.toString();
        } else if (isInnerClass()) {
            return getInnerClass().toString();
        }
        return type.typeString(getName().toString());
    }

    
Print for debugging
/**
     * Print for debugging
     */
    public void print(PrintStream out) {
        if (isPublic()) {
            out.print("public ");
        }
        if (isPrivate()) {
            out.print("private ");
        }
        if (isProtected()) {
            out.print("protected ");
        }
        if (isFinal()) {
            out.print("final ");
        }
        if (isStatic()) {
            out.print("static ");
        }
        if (isSynchronized()) {
            out.print("synchronized ");
        }
        if (isAbstract()) {
            out.print("abstract ");
        }
        if (isNative()) {
            out.print("native ");
        }
        if (isVolatile()) {
            out.print("volatile ");
        }
        if (isTransient()) {
            out.print("transient ");
        }
        out.println(toString() + ";");
    }

    public void cleanup(Environment env) {
        documentation = null;
        if (isMethod() && value != null) {
            int cost = 0;
            if (isPrivate() || isInitializer()) {
                value = Statement.empty;
            } else if ((cost =
                        ((Statement)value)
                       .costInline(Statement.MAXINLINECOST, null, null))
                                >= Statement.MAXINLINECOST) {
                // will never be inlined
                value = Statement.empty;
            } else {
                try {
                    if (!isInlineable(null, true)) {
                        value = Statement.empty;
                    }
                }
                catch (ClassNotFound ee) { }
            }
            if (value != Statement.empty && env.dump()) {
                env.output("[after cleanup of " + getName() + ", " +
                           cost + " expression cost units remain]");
            }
        } else if (isVariable()) {
            if (isPrivate() || !isFinal() || type.isType(TC_ARRAY)) {
                value = null;
            }
        }
    }
}