/*******************************************************************************
 * 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.
 * 
 * This file is a derivative of code released by the University of
 * California under the terms listed below.  
 *
 * Refinement Analysis Tools is Copyright (c) 2007 The Regents of the
 * University of California (Regents). Provided that this notice and
 * the following two paragraphs are included in any distribution of
 * Refinement Analysis Tools or its derivative work, Regents agrees
 * not to assert any of Regents' copyright rights in Refinement
 * Analysis Tools against recipient for recipient's reproduction,
 * preparation of derivative works, public display, public
 * performance, distribution or sublicensing of Refinement Analysis
 * Tools and derivative works, in source code and object code form.
 * This agreement not to assert does not confer, by implication,
 * estoppel, or otherwise any license or rights in any intellectual
 * property of Regents, including, but not limited to, any patents
 * of Regents or Regents' employees.
 * 
 * IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT,
 * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
 * INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE
 * AND ITS DOCUMENTATION, EVEN IF REGENTS HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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 * WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE AND ACCOMPANYING
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 * IS". REGENTS HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
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 */
package com.ibm.wala.demandpa.flowgraph;

import com.ibm.wala.ipa.callgraph.propagation.FilteredPointerKey.TypeFilter;

/**
 * @author Manu Sridharan
 * 
 */
public class AssignBarLabel implements IFlowLabelWithFilter {

  private static final AssignBarLabel noFilter = new AssignBarLabel(null);

  private final TypeFilter filter;

  private AssignBarLabel(TypeFilter filter) {
    this.filter = filter;
  }

  public static AssignBarLabel noFilter() {
    return noFilter;
  }

  public static AssignBarLabel make(TypeFilter filter) {
    return new AssignBarLabel(filter);
  }

  /*
   * (non-Javadoc)
   * @see demandGraph.IFlowLabel#bar()
   */
  @Override
  public AssignLabel bar() {
    return (this == noFilter) ? AssignLabel.noFilter() : AssignLabel.make(filter);
  }

  /*
   * (non-Javadoc)
   * @see demandGraph.IFlowLabel#visit(demandGraph.IFlowLabel.IFlowLabelVisitor, java.lang.Object)
   */
  @Override
  public void visit(IFlowLabelVisitor v, Object dst) throws IllegalArgumentException {
    if (v == null) {
      throw new IllegalArgumentException("v == null");
    }
    v.visitAssignBar(this, dst);
  }

  @Override
  public boolean isBarred() {
    return true;
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((filter == null) ? 0 : filter.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    final AssignBarLabel other = (AssignBarLabel) obj;
    if (filter == null) {
      if (other.filter != null)
        return false;
    } else if (!filter.equals(other.filter))
      return false;
    return true;
  }

  @Override
  public TypeFilter getFilter() {
    return filter;
  }
}