com.google.code.morphia.utils.IterHelper Maven / Gradle / Ivy

Go to download
package com.google.code.morphia.utils;


import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.bson.BSONObject;


/**
 * Helper to allow for optimizations for different types of Map/Collections
 *
 * @param  The key type of the map
 * @param  The value type of the map/collection
 * @author Scott Hernandez
 */
public class IterHelper {
  @SuppressWarnings({ "unchecked", "rawtypes" })
  public void loopMap(final Object x, final MapIterCallback iter) {
    if (x == null) {
      return;
    }

    if (x instanceof Collection) {
      throw new IllegalArgumentException("call loop instead");
    }

    if (x instanceof HashMap) {
      if (((HashMap) x).isEmpty()) {
        return;
      }

      final HashMap hm = (HashMap) x;
      for (final Entry e : hm.entrySet()) {
        iter.eval((T) e.getKey(), (V) e.getValue());
      }
      return;
    }
    if (x instanceof Map) {
      final Map m = (Map) x;
      for (final Object k : m.keySet()) {
        iter.eval((T) k, (V) m.get(k));
      }
      return;
    }
    if (x instanceof BSONObject) {
      final BSONObject m = (BSONObject) x;
      for (final String k : m.keySet()) {
        iter.eval((T) k, (V) m.get(k));
      }
    }

  }

  @SuppressWarnings({ "unchecked" })
  public void loop(final Object x, final IterCallback iter) {
    if (x == null) {
      return;
    }

    if (x instanceof Map) {
      throw new IllegalArgumentException("call loopMap instead");
    }

    if (x instanceof List) {
      final List l = (List) x;
      for (final Object o : l) {
        iter.eval((V) o);
      }
    }
  }

  /**
   * Calls eval for each entry found, or just once if the "x" isn't iterable/collection/list/etc. with "x"
   */
  @SuppressWarnings({ "unchecked" })
  public void loopOrSingle(final Object x, final IterCallback iter) {
    if (x == null) {
      return;
    }

    //A collection
    if (x instanceof Collection) {
      final Collection l = (Collection) x;
      for (final Object o : l) {
        iter.eval((V) o);
      }
      return;
    }

    //An array of Object[]
    if (x.getClass().isArray()) {
      for (final Object o : (Object[]) x) {
        iter.eval((V) o);
      }
      return;
    }

    iter.eval((V) x);
  }

  public abstract static class MapIterCallback {
    public abstract void eval(T t, V v);
  }

  public abstract static class IterCallback {
    public abstract void eval(V v);
  }
}