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 * Copyright (c) 2014, 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.
 *
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package org.openjdk.btrace.instr.templates;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

/**
 * A generic base class for {@linkplain TemplateExpander} implementations
 *
 * @author Jaroslav Bachorik
 */
public abstract class BaseTemplateExpander implements TemplateExpander {
  private final Set<Template> supportedTemplates = new HashSet<>();

  private Template lastTemplate = null;

  public BaseTemplateExpander(Template... templates) {
    supportedTemplates.addAll(Arrays.asList(templates));
    BTraceTemplates.registerTemplates(templates);
  }

  @Override
  public final Result expand(TemplateExpanderVisitor v, Template t) {
    if (lastTemplate == null) {
      if (t == null || !supportedTemplates.contains(t)) {
        return Result.IGNORED;
      }

      recordTemplate(t);
      lastTemplate = t;
      return Result.CLAIMED;
    } else {
      if (lastTemplate.equals(t)) {
        recordTemplate(t);
        return Result.CLAIMED;
      } else {
        Result r = expandTemplate(v, lastTemplate);
        lastTemplate = t;
        return t != null ? r : Result.IGNORED;
      }
    }
  }

  protected abstract void recordTemplate(Template t);

  protected abstract Result expandTemplate(TemplateExpanderVisitor v, Template t);
}
