org.camunda.bpm.engine.impl.core.variable.scope.VariableStore Maven / Gradle / Ivy

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/*
 * Copyright Camunda Services GmbH and/or licensed to Camunda Services GmbH
 * under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership. Camunda licenses this file to you under the Apache License,
 * Version 2.0; 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.camunda.bpm.engine.impl.core.variable.scope;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.camunda.bpm.engine.impl.ProcessEngineLogger;
import org.camunda.bpm.engine.impl.core.variable.CoreVariableInstance;

/**
 * @author Thorben Lindhauer
 *
 */
public class VariableStore {

  protected VariablesProvider variablesProvider;
  protected Map variables;

  protected Map removedVariables = new HashMap();

  protected List> observers;

  public VariableStore() {
    this(VariableCollectionProvider.emptyVariables());
  }

  public VariableStore(VariablesProvider provider, VariableStoreObserver... observers) {
    this.variablesProvider = provider;
    this.observers = new ArrayList>();
    this.observers.addAll(Arrays.asList(observers));
  }

  /**
   * The variables provider can be exchanged as long as the variables are not yet initialized
   */
  public void setVariablesProvider(VariablesProvider variablesProvider) {
    if (variables != null) {
      // already initialized
      return;
    }
    else {
      this.variablesProvider = variablesProvider;
    }

  }

  protected Map getVariablesMap() {
    forceInitialization();

    return variables;
  }

  protected Map getVariablesMap(Collection variableNames) {
    if (variableNames == null) {
      return getVariablesMap();
    }

    Map result = new HashMap();

    if (isInitialized()) {
      for (String variableName : variableNames) {
        if (variables.containsKey(variableName)) {
          result.put(variableName, variables.get(variableName));
        }
      }
    }
    else {
      // in this case we don't initialize the variables map,
      // otherwise it would most likely contain only a subset
      // of existing variables
      for (T variable : variablesProvider.provideVariables(variableNames)) {
        result.put(variable.getName(), variable);
      }
    }

    return result;
  }

  public T getRemovedVariable(String name) {
    return removedVariables.get(name);
  }

  public T getVariable(String name) {

    return getVariablesMap().get(name);
  }

  public List getVariables() {
    return new ArrayList(getVariablesMap().values());
  }

  public List getVariables(Collection variableNames) {
    return new ArrayList(getVariablesMap(variableNames).values());
  }

  public void addVariable(T value) {

    if (containsKey(value.getName())) {
      throw ProcessEngineLogger.CORE_LOGGER.duplicateVariableInstanceException(value);
    }

    getVariablesMap().put(value.getName(), value);

    for (VariableStoreObserver listener : observers) {
      listener.onAdd(value);
    }

    if(removedVariables.containsKey(value.getName())){
      removedVariables.remove(value.getName());
    }
  }

  public void updateVariable(T value)
  {
    if (!containsKey(value.getName()))
    {
      throw ProcessEngineLogger.CORE_LOGGER.duplicateVariableInstanceException(value);
    }
  }

  public boolean isEmpty() {
    return getVariablesMap().isEmpty();
  }

  public boolean containsValue(T value) {
    return getVariablesMap().containsValue(value);
  }

  public boolean containsKey(String key) {
    return getVariablesMap().containsKey(key);
  }

  public Set getKeys() {
    return new HashSet(getVariablesMap().keySet());
  }

  public boolean isInitialized() {
    return variables != null;
  }

  public void forceInitialization() {
    if (!isInitialized()) {
      variables = new HashMap();

      for (T variable : variablesProvider.provideVariables()) {
        variables.put(variable.getName(), variable);
      }
    }
  }

  public T removeVariable(String variableName) {

    if (!getVariablesMap().containsKey(variableName)) {
      return null;
    }

    T value = getVariablesMap().remove(variableName);

    for (VariableStoreObserver observer : observers) {
      observer.onRemove(value);
    }

    removedVariables.put(variableName, value);

    return value;
  }

  public void removeVariables() {
    Iterator valuesIt = getVariablesMap().values().iterator();

    removedVariables.putAll(variables);
    while (valuesIt.hasNext()) {
      T nextVariable = valuesIt.next();

      valuesIt.remove();

      for (VariableStoreObserver observer : observers) {
        observer.onRemove(nextVariable);
      }
    }
  }

  public void addObserver(VariableStoreObserver observer) {
    observers.add(observer);
  }

  public void removeObserver(VariableStoreObserver observer) {
    observers.remove(observer);
  }

  public static interface VariableStoreObserver {

    void onAdd(T variable);

    void onRemove(T variable);
  }

  public static interface VariablesProvider {

    Collection provideVariables();

    Collection provideVariables(Collection variableNames);

  }

  public boolean isRemoved(String variableName) {
    return removedVariables.containsKey(variableName);
  }

}