Java设计模式-建造者模式

1：使用场景

1）相同的方法，不同的执行顺序，产生不同的事件结果

2）多个部件或零件，都可以装配到一个对象中，但是产生的运行结果又不同

3）产品类非常复杂，或者产品类中的调用顺序不同产生了不同的作用

4）当初始化一个对象特别复杂，如参数多。

2：UML图

3：代码举例

public abstract class Computer {    protected String mBoard;    protected String mDisplay;    protected String mOS;        public void setBoard(String board){    mBoard=board;    }        public void setDisplay(String display){    mDisplay=display;    }        public abstract void setOS();        }

public  class Macbook extends Computer{    public Macbook(){        }        public  void setOS(){    mOS= "Mac OS X 10.10";    }        }

public abstract class Builder {    public abstract void buildBoard(String board);        public abstract void buildDisplay(String display);        public abstract void buildOS();        public abstract Computer createComputer();}

public  class MacbookBuilder extends Builder{Computer mComputer=new Macbook();@Overridepublic void buildBoard(String board) {mComputer.setBoard(board);}@Overridepublic void buildDisplay(String display) {mComputer.setDisplay(display);}@Overridepublic void buildOS() {mComputer.setOS();}@Overridepublic Computer createComputer() {return mComputer;}    }

public class Director {Builder mBuilder=null;public Director(Builder b){b=mBuilder;}public void construct(String board,String display){mBuilder.buildBoard(board);mBuilder.buildDisplay(display);mBuilder.buildOS();}}

public  class Client {public  static void main(String[] args){Builder mBuilder=new MacbookBuilder();Director mDirector=new Director(mBuilder);mDirector.construct("Intel主板", "Retina显示器");}}

4: Android中的建造者模式

private void showDialog(Context context) {      AlertDialog.Builder builder = new AlertDialog.Builder(context);      builder.setIcon(R.drawable.icon);      builder.setTitle("Title");      builder.setMessage("Message");      builder.setPositiveButton("Button1",              new DialogInterface.OnClickListener() {                  public void onClick(DialogInterface dialog, int whichButton) {                      setTitle("点击了对话框上的Button1");                  }              });      builder.setNeutralButton("Button2",              new DialogInterface.OnClickListener() {                  public void onClick(DialogInterface dialog, int whichButton) {                      setTitle("点击了对话框上的Button2");                  }              });      builder.setNegativeButton("Button3",              new DialogInterface.OnClickListener() {                  public void onClick(DialogInterface dialog, int whichButton) {                      setTitle("点击了对话框上的Button3");                  }              });      builder.create().show();  // 构建AlertDialog， 并且显示} 

public static class Builder {    private final AlertController.AlertParams P;    private int mTheme;    public Builder(Context context) {        this(context, resolveDialogTheme(context, 0));    }    public Builder(Context context, int theme) {        P = new AlertController.AlertParams(new ContextThemeWrapper(                context, resolveDialogTheme(context, theme)));        mTheme = theme;    }    public Context getContext() {        return P.mContext;    }    public Builder setTitle(int titleId) {        P.mTitle = P.mContext.getText(titleId);        return this;    }    public Builder setTitle(CharSequence title) {        P.mTitle = title;        return this;    }    public Builder setCustomTitle(View customTitleView) {        P.mCustomTitleView = customTitleView;        return this;    }    public Builder setMessage(int messageId) {        P.mMessage = P.mContext.getText(messageId);        return this;    }    public Builder setMessage(CharSequence message) {        P.mMessage = message;        return this;    }    public Builder setIcon(int iconId) {        P.mIconId = iconId;        return this;    }    public Builder setIcon(Drawable icon) {        P.mIcon = icon;        return this;    }    public Builder setIconAttribute(int attrId) {        TypedValue out = new TypedValue();        P.mContext.getTheme().resolveAttribute(attrId, out, true);        P.mIconId = out.resourceId;        return this;    }    public Builder setPositiveButton(int textId, final OnClickListener listener) {        P.mPositiveButtonText = P.mContext.getText(textId);        P.mPositiveButtonListener = listener;        return this;    }    public Builder setPositiveButton(CharSequence text, final OnClickListener listener) {        P.mPositiveButtonText = text;        P.mPositiveButtonListener = listener;        return this;    }    public Builder setNegativeButton(int textId, final OnClickListener listener) {        P.mNegativeButtonText = P.mContext.getText(textId);        P.mNegativeButtonListener = listener;        return this;    }    public Builder setNegativeButton(CharSequence text, final OnClickListener listener) {        P.mNegativeButtonText = text;        P.mNegativeButtonListener = listener;        return this;    }    public Builder setNeutralButton(int textId, final OnClickListener listener) {        P.mNeutralButtonText = P.mContext.getText(textId);        P.mNeutralButtonListener = listener;        return this;    }    public Builder setNeutralButton(CharSequence text, final OnClickListener listener) {        P.mNeutralButtonText = text;        P.mNeutralButtonListener = listener;        return this;    }    public Builder setCancelable(boolean cancelable) {        P.mCancelable = cancelable;        return this;    }    public Builder setOnCancelListener(OnCancelListener onCancelListener) {        P.mOnCancelListener = onCancelListener;        return this;    }    public Builder setOnDismissListener(OnDismissListener onDismissListener) {        P.mOnDismissListener = onDismissListener;        return this;    }    public Builder setOnKeyListener(OnKeyListener onKeyListener) {        P.mOnKeyListener = onKeyListener;        return this;    }    public Builder setItems(int itemsId, final OnClickListener listener) {        P.mItems = P.mContext.getResources().getTextArray(itemsId);        P.mOnClickListener = listener;        return this;    }    public Builder setItems(CharSequence[] items, final OnClickListener listener) {        P.mItems = items;        P.mOnClickListener = listener;        return this;    }    public Builder setAdapter(final ListAdapter adapter, final OnClickListener listener) {        P.mAdapter = adapter;        P.mOnClickListener = listener;        return this;    }    public Builder setCursor(final Cursor cursor, final OnClickListener listener,            String labelColumn) {        P.mCursor = cursor;        P.mLabelColumn = labelColumn;        P.mOnClickListener = listener;        return this;    }    public Builder setMultiChoiceItems(int itemsId, boolean[] checkedItems,             final OnMultiChoiceClickListener listener) {        P.mItems = P.mContext.getResources().getTextArray(itemsId);        P.mOnCheckboxClickListener = listener;        P.mCheckedItems = checkedItems;        P.mIsMultiChoice = true;        return this;    }    public Builder setMultiChoiceItems(CharSequence[] items, boolean[] checkedItems,             final OnMultiChoiceClickListener listener) {        P.mItems = items;        P.mOnCheckboxClickListener = listener;        P.mCheckedItems = checkedItems;        P.mIsMultiChoice = true;        return this;    }    public Builder setMultiChoiceItems(Cursor cursor, String isCheckedColumn, String labelColumn,             final OnMultiChoiceClickListener listener) {        P.mCursor = cursor;        P.mOnCheckboxClickListener = listener;        P.mIsCheckedColumn = isCheckedColumn;        P.mLabelColumn = labelColumn;        P.mIsMultiChoice = true;        return this;    }    public Builder setSingleChoiceItems(int itemsId, int checkedItem,             final OnClickListener listener) {        P.mItems = P.mContext.getResources().getTextArray(itemsId);        P.mOnClickListener = listener;        P.mCheckedItem = checkedItem;        P.mIsSingleChoice = true;        return this;    }    public Builder setSingleChoiceItems(Cursor cursor, int checkedItem, String labelColumn,             final OnClickListener listener) {        P.mCursor = cursor;        P.mOnClickListener = listener;        P.mCheckedItem = checkedItem;        P.mLabelColumn = labelColumn;        P.mIsSingleChoice = true;        return this;    }    public Builder setSingleChoiceItems(CharSequence[] items, int checkedItem, final OnClickListener listener) {        P.mItems = items;        P.mOnClickListener = listener;        P.mCheckedItem = checkedItem;        P.mIsSingleChoice = true;        return this;    }     public Builder setSingleChoiceItems(ListAdapter adapter, int checkedItem, final OnClickListener listener) {        P.mAdapter = adapter;        P.mOnClickListener = listener;        P.mCheckedItem = checkedItem;        P.mIsSingleChoice = true;        return this;    }    public Builder setOnItemSelectedListener(final AdapterView.OnItemSelectedListener listener) {        P.mOnItemSelectedListener = listener;        return this;    }    public Builder setView(View view) {        P.mView = view;        P.mViewSpacingSpecified = false;        return this;    }    public Builder setInverseBackgroundForced(boolean useInverseBackground) {        P.mForceInverseBackground = useInverseBackground;        return this;    }    public AlertDialog create() {        final AlertDialog dialog = new AlertDialog(P.mContext, mTheme, false);        P.apply(dialog.mAlert);        dialog.setCancelable(P.mCancelable);        if (P.mCancelable) {            dialog.setCanceledOnTouchOutside(true);        }        dialog.setOnCancelListener(P.mOnCancelListener);        dialog.setOnDismissListener(P.mOnDismissListener);        if (P.mOnKeyListener != null) {            dialog.setOnKeyListener(P.mOnKeyListener);        }        return dialog;    }    public AlertDialog show() {        AlertDialog dialog = create();        dialog.show();        return dialog;    }}