StoreExpr.java :  » Database-DBMS » db4o-6.4 » EDU » purdue » cs » bloat » tree » Java Open Source

/* Copyright (C) 2004 - 2007  db4objects Inc.  http://www.db4o.com

This file is part of the db4o open source object database.

db4o is free software; you can redistribute it and/or modify it under
the terms of version 2 of the GNU General Public License as published
by the Free Software Foundation and as clarified by db4objects' GPL 
interpretation policy, available at
http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
Suite 350, San Mateo, CA 94403, USA.

db4o 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
for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. */
package EDU.purdue.cs.bloat.tree;

import EDU.purdue.cs.bloat.editor.*;

/**
 * StoreExpr represents a store of an expression into a memory location.
 * 
 * @see MemExpr
 */
public class StoreExpr extends Expr implements Assign {
  MemExpr target;

  Expr expr;

  /**
   * Constructor.
   * 
   * @param target
   *            The memory location (or local variable, etc.) into which expr
   *            is stored.
   * @param expr
   *            An expression whose value is to be stored.
   * @param type
   *            The type of this expression.
   */
  public StoreExpr(final MemExpr target, final Expr expr, final Type type) {
    super(type);

    this.target = target;
    this.expr = expr;

    target.setParent(this);
    expr.setParent(this);
  }

  /**
   * Returns the <tt>MemExpr</tt> into which the expression is stored.
   */
  public DefExpr[] defs() {
    return new DefExpr[] { target };
  }

  /**
   * Returns the memory location (or local variable) into which the expression
   * is stored.
   */
  public MemExpr target() {
    return target;
  }

  /**
   * Returns the expression being stored.
   */
  public Expr expr() {
    return expr;
  }

  public void visitForceChildren(final TreeVisitor visitor) {
    if (visitor.reverse()) {
      target.visitOnly(visitor);
      expr.visit(visitor);
      target.visitChildren(visitor);
    } else {
      target.visitChildren(visitor);
      expr.visit(visitor);
      target.visitOnly(visitor);
    }
  }

  public void visit(final TreeVisitor visitor) {
    visitor.visitStoreExpr(this);
  }

  public int exprHashCode() {
    return 22 + target.exprHashCode() ^ expr.exprHashCode();
  }

  public boolean equalsExpr(final Expr other) {
    return (other instanceof StoreExpr)
        && ((StoreExpr) other).target.equalsExpr(target)
        && ((StoreExpr) other).expr.equalsExpr(expr);
  }

  public Object clone() {
    return copyInto(new StoreExpr((MemExpr) target.clone(), (Expr) expr
        .clone(), type));
  }
}