All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.rt.storage.api.client.util.ArrayValueMap Maven / Gradle / Ivy

Go to download 

package com.rt.storage.api.client.util;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

/**
 * Collects the array values of a key/value data object, writing the fields or map values only after
 * all values have been collected.
 *
 * 
The typical application for this is when parsing JSON or XML when the value type is known to
 * be an array. It stores the values in a collection during the parsing, and only when the parsing
 * of an object is finished does it convert the collection into an array and stores it.
 *
 * 
Use {@link #put(String, Class, Object)} when the destination object is a map with string keys
 * and whose values accept an array of objects. Use {@link #put(Field, Class, Object)} when setting
 * the value of a field using reflection, assuming its type accepts an array of objects. One can
 * potentially use both {@code put} methods for example on an instance of {@link GenericData}.
 *
 * 
Implementation is not thread-safe. For a thread-safe choice instead use an implementation of
 * {@link ConcurrentMap}.
 *
 * @since 1.4
 * @author Yaniv Inbar
 */
public final class ArrayValueMap {

  /** Array values on a particular field. */
  static class ArrayValue {

    /** Array component type. */
    final Class componentType;

    /** Values to be stored in the array. */
    final ArrayList values = new ArrayList();

    /** @param componentType array component type */
    ArrayValue(Class componentType) {
      this.componentType = componentType;
    }

    /** Creates a new array whose content matches that of the {@link #values}. */
    Object toArray() {
      return Types.toArray(values, componentType);
    }

    /**
     * Adds a given value to the array, checking the given component type matches the previously
     * stored component type.
     */
    void addValue(Class componentType, Object value) {
      Preconditions.checkArgument(componentType == this.componentType);
      values.add(value);
    }
  }

  /** Map from key name to its array values. */
  private final Map keyMap = ArrayMap.create();

  /** Map from field to its array values. */
  private final Map fieldMap = ArrayMap.create();

  /** Destination object whose fields must be set, or destination map whose values must be set. */
  private final Object destination;

  /**
   * @param destination destination object whose fields must be set, or destination map whose values
   *     must be set
   */
  public ArrayValueMap(Object destination) {
    this.destination = destination;
  }

  /**
   * Sets the fields of the given object using the values collected during parsing of the object's
   * fields.
   */
  public void setValues() {
    for (Map.Entry entry : keyMap.entrySet()) {
      @SuppressWarnings("unchecked")
      Map destinationMap = (Map) destination;
      destinationMap.put(entry.getKey(), entry.getValue().toArray());
    }
    for (Map.Entry entry : fieldMap.entrySet()) {
      FieldInfo.setFieldValue(entry.getKey(), destination, entry.getValue().toArray());
    }
  }

  /**
   * Puts an additional value for the given field, accumulating values on repeated calls on the same
   * field.
   *
   * @param field field
   * @param arrayComponentType array component type
   * @param value value
   */
  public void put(Field field, Class arrayComponentType, Object value) {
    ArrayValueMap.ArrayValue arrayValue = fieldMap.get(field);
    if (arrayValue == null) {
      arrayValue = new ArrayValue(arrayComponentType);
      fieldMap.put(field, arrayValue);
    }
    arrayValue.addValue(arrayComponentType, value);
  }

  /**
   * Puts an additional value for the given key name, accumulating values on repeated calls on the
   * same key name.
   *
   * @param keyName key name
   * @param arrayComponentType array component type
   * @param value value
   */
  public void put(String keyName, Class arrayComponentType, Object value) {
    ArrayValueMap.ArrayValue arrayValue = keyMap.get(keyName);
    if (arrayValue == null) {
      arrayValue = new ArrayValue(arrayComponentType);
      keyMap.put(keyName, arrayValue);
    }
    arrayValue.addValue(arrayComponentType, value);
  }
}
    

    

    

            

    

            



    
    






    
© 2015 - 2024 Weber Informatics LLC | Privacy Policy