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/**
 * Copyright (C) 2006-2015 phloc systems
 * http://www.phloc.com
 * office[at]phloc[dot]com
 *
 * 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 com.phloc.commons.collections.attrs;

import java.util.Collection;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.NotThreadSafe;

import com.phloc.commons.ICloneable;
import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.annotations.OverrideOnDemand;
import com.phloc.commons.annotations.ReturnsMutableCopy;
import com.phloc.commons.collections.ContainerHelper;
import com.phloc.commons.equals.EqualsUtils;
import com.phloc.commons.hash.HashCodeGenerator;
import com.phloc.commons.state.EChange;
import com.phloc.commons.state.EContinue;
import com.phloc.commons.string.ToStringGenerator;

/**
 * Base class for all kind of string-object mapping container. This
 * implementation is not thread-safe!
 * 
 * @author Philip Helger
 */
@NotThreadSafe
public class MapBasedAttributeContainer extends AbstractReadonlyAttributeContainer implements IAttributeContainer, ICloneable 
{
  /**
   * attribute storage.
   */
  private final Map  m_aAttrs;

  public MapBasedAttributeContainer ()
  {
    m_aAttrs = new HashMap  ();
  }

  public MapBasedAttributeContainer (@Nonnull final Map  aMap)
  {
    ValueEnforcer.notNull (aMap, "Map");
    m_aAttrs = ContainerHelper.newMap (aMap);
  }

  public MapBasedAttributeContainer (@Nonnull final IReadonlyAttributeContainer aCont)
  {
    ValueEnforcer.notNull (aCont, "Container");
    // Must already be a copy!
    m_aAttrs = aCont.getAllAttributes ();
  }

  public boolean containsAttribute (@Nullable final String sName)
  {
    // ConcurrentHashMap cannot handle null keys
    return sName != null && m_aAttrs.containsKey (sName);
  }

  @Nonnull
  @ReturnsMutableCopy
  public Map  getAllAttributes ()
  {
    return ContainerHelper.newMap (m_aAttrs);
  }

  @Nullable
  public Object getAttributeObject (@Nullable final String sName)
  {
    // ConcurrentHashMap cannot handle null keys
    return sName == null ? null : m_aAttrs.get (sName);
  }

  /**
   * Internal callback method that can be used to check constraints on an
   * attribute name or value.
   * 
   * @param sName
   *        The attribute name. Never null.
   * @param aValue
   *        The attribute value. Never null.
   * @return {@link EContinue#CONTINUE} to indicate that the name-value-pair is
   *         OK. May not be null.
   */
  @OverrideOnDemand
  @Nonnull
  protected EContinue onBeforeSetAttributeValue (@Nonnull final String sName, @Nonnull final Object aValue)
  {
    return EContinue.CONTINUE;
  }

  @Nonnull
  public EChange setAttribute (@Nonnull final String sName, @Nullable final Object aValue)
  {
    ValueEnforcer.notNull (sName, "Name");

    if (aValue == null)
      return removeAttribute (sName);

    // Callback for checks etc.
    if (onBeforeSetAttributeValue (sName, aValue).isBreak ())
      return EChange.UNCHANGED;

    final Object aOldValue = m_aAttrs.put (sName, aValue);
    return EChange.valueOf (!EqualsUtils.equals (aValue, aOldValue));
  }

  @Nonnull
  public final EChange setAttribute (@Nonnull final String sName, final boolean dValue)
  {
    return setAttribute (sName, Boolean.valueOf (dValue));
  }

  @Nonnull
  public final EChange setAttribute (@Nonnull final String sName, final int nValue)
  {
    return setAttribute (sName, Integer.valueOf (nValue));
  }

  @Nonnull
  public final EChange setAttribute (@Nonnull final String sName, final long nValue)
  {
    return setAttribute (sName, Long.valueOf (nValue));
  }

  @Nonnull
  public final EChange setAttribute (@Nonnull final String sName, final double dValue)
  {
    return setAttribute (sName, Double.valueOf (dValue));
  }

  @Nonnull
  public final EChange setAttributes (@Nullable final Map  aValues)
  {
    EChange ret = EChange.UNCHANGED;
    if (aValues != null)
      for (final Map.Entry  aEntry : aValues.entrySet ())
        ret = ret.or (setAttribute (aEntry.getKey (), aEntry.getValue ()));
    return ret;
  }

  @Nonnull
  public final EChange setAttributes (@Nullable final IReadonlyAttributeContainer aValues)
  {
    if (aValues == null)
      return EChange.UNCHANGED;
    return setAttributes (aValues.getAllAttributes ());
  }

  /**
   * Internal callback method that can be used to avoid removal of an attribute.
   * 
   * @param sName
   *        The attribute name. Never null.
   * @return {@link EContinue#CONTINUE} to indicate that the name-value-pair is
   *         OK. May not be null.
   */
  @OverrideOnDemand
  @Nonnull
  protected EContinue onBeforeRemoveAttribute (@Nonnull final String sName)
  {
    return EContinue.CONTINUE;
  }

  @Nonnull
  public EChange removeAttribute (@Nullable final String sName)
  {
    if (sName == null)
      return EChange.UNCHANGED;

    // Callback method
    if (onBeforeRemoveAttribute (sName).isBreak ())
      return EChange.UNCHANGED;

    // Returned value may be null
    return EChange.valueOf (m_aAttrs.remove (sName) != null);
  }

  @Nonnull
  public Enumeration  getAttributeNames ()
  {
    // Build an enumerator on top of the set
    return ContainerHelper.getEnumeration (m_aAttrs.keySet ());
  }

  @Nonnull
  @ReturnsMutableCopy
  public Set  getAllAttributeNames ()
  {
    return ContainerHelper.newSet (m_aAttrs.keySet ());
  }

  @Nonnull
  @ReturnsMutableCopy
  public Collection