REF.java

/*
 * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 Lesser 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.
 *
 * Additionally licensed with:
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.spf4j.zel.instr;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import org.spf4j.base.Arrays;
import org.spf4j.zel.vm.AssignableValue;
import org.spf4j.zel.vm.ExecutionContext;
import org.spf4j.zel.vm.SuspendedException;

/**
 * @author zoly
 */
public final class REF extends Instruction {

  private static final long serialVersionUID = 1L;

  public static final Instruction INSTANCE = new REF();

  private REF() {
  }

  @Override
  public int execute(final ExecutionContext context)
          throws ExecutionException, SuspendedException, InterruptedException {
    final Object[] vals = context.tuple();
    context.popSyncStackVals(vals);
    final Object ref = vals[1];
    final Object relTo = vals[0];
    final Object relativeTo;
    if (relTo instanceof AssignableValue) {
      Object obj = ((AssignableValue) relTo).get();
      if (obj == null) {
        obj = new HashMap();
        ((AssignableValue) relTo).assign(obj);
      }
      relativeTo = obj;
    } else {
      relativeTo = relTo;
    }
    if (relativeTo instanceof Map) {
      context.push(new MapDeref(relativeTo, ref));

    } else if (relativeTo instanceof Object[]) {
      context.push(new ArrayDeref(relativeTo, ref));

    } else {
      context.push(new JavaMethodDeref(relativeTo, ref, context));
    }
    return 1;
  }

  @Override
  public Object[] getParameters() {
    return Arrays.EMPTY_OBJ_ARRAY;
  }

  private static final class MapDeref implements AssignableValue {

    private final Object relativeTo;
    private final Object ref;

    MapDeref(final Object relativeTo, final Object ref) {
      this.relativeTo = relativeTo;
      this.ref = ref;
    }

    @Override
    public void assign(final Object object) {
      ((Map) relativeTo).put(ref, object);
    }

    @Override
    public Object get() {
      return ((Map) relativeTo).get(ref);
    }
  }

  private static final class ArrayDeref implements AssignableValue {

    private final Object relativeTo;
    private final Object ref;

    ArrayDeref(final Object relativeTo, final Object ref) {
      this.relativeTo = relativeTo;
      this.ref = ref;
    }

    @Override
    public void assign(final Object object) {
      ((Object[]) relativeTo)[((Number) ref).intValue()] = object;
    }

    @Override
    public Object get() {
      return ((Object[]) relativeTo)[((Number) ref).intValue()];
    }
  }

  private static final class JavaMethodDeref implements AssignableValue {

    private final Object relativeTo;
    private final Object ref;
    private final ExecutionContext ctx;

    JavaMethodDeref(final Object relativeTo, final Object ref, final ExecutionContext ctx) {
      this.relativeTo = relativeTo;
      this.ref = ref;
      this.ctx = ctx;
    }

    @Override
    public void assign(final Object object) {
      throw new UnsupportedOperationException("Cannot assign " + object + " to "
              + relativeTo + '.' + ref);
    }

    @Override
    public Object get() {
      return ctx.newJavaCall(relativeTo, (String) ref);
    }
  }
}