org.robobinding.itempresentationmodel.BeanCursor Maven / Gradle / Ivy

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package org.robobinding.itempresentationmodel;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.robobinding.internal.java_beans.PropertyDescriptor;
import org.robobinding.property.PropertyAccessor;
import org.robobinding.property.PropertyUtils;

import android.database.AbstractCursor;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

/**
 * 
 * @since 1.0
 * @version $Revision: 1.0 $
 * @author Cheng Wei
 */
public class BeanCursor extends AbstractCursor implements TypedCursor {

    private List beans;
    private Map> propertyNameToAccessors;

    public BeanCursor(Collection beans, Class beanClass) {
	checkNotNull(beans, "beans can not be null");
	checkNotNull(beanClass, "beanClass can not be null");

	this.beans = Lists.newArrayList(beans);
	initializeProperties(beanClass);
    }

    private void initializeProperties(Class beanClass) {
	List propertyDescriptors = PropertyUtils.getPropertyDescriptors(beanClass);
	propertyNameToAccessors = Maps.newHashMap();
	for (PropertyDescriptor propertyDescriptor : propertyDescriptors) {
	    PropertyAccessor propertyAccessor = new PropertyAccessor(propertyDescriptor, beanClass);
	    propertyNameToAccessors.put(propertyDescriptor.getName(), propertyAccessor);
	}
    }

    @Override
    public int getCount() {
	return beans.size();
    }

    private transient volatile String[] propertyNamesCache;

    @Override
    public String[] getColumnNames() {
	if (propertyNamesCache == null) {
	    Set propertyNames = propertyNameToAccessors.keySet();
	    propertyNamesCache = propertyNames.toArray(new String[0]);
	}
	return propertyNamesCache;
    }

    @Override
    public String getString(int column) {
	return (String) getColumnValue(column);
    }

    @Override
    public short getShort(int column) {
	return (Short) getColumnValue(column);
    }

    @Override
    public int getInt(int column) {
	return (Integer) getColumnValue(column);
    }

    @Override
    public long getLong(int column) {
	return (Long) getColumnValue(column);
    }

    @Override
    public float getFloat(int column) {
	return (Float) getColumnValue(column);
    }

    @Override
    public double getDouble(int column) {
	return (Double) getColumnValue(column);
    }

    @Override
    public boolean isNull(int column) {
	Object value = getColumnValue(column);
	return value == null;
    }

    private Object getColumnValue(int column) {
	checkArgument(column < getNumColumns(), "column '" + column + "' is out of bound");
	PropertyAccessor propertyAccesor = mapColumnToPropertyAccessor(column);
	return propertyAccesor.getValue(getBean());
    }

    private PropertyAccessor mapColumnToPropertyAccessor(int column) {
	String propertyName = mapColumnToPropertyName(column);
	PropertyAccessor propertyAccesor = propertyNameToAccessors.get(propertyName);
	return propertyAccesor;
    }

    private String mapColumnToPropertyName(int column) {
	return getColumnName(column);
    }

    private int getNumColumns() {
	return propertyNameToAccessors.size();
    }

    private Object getBean() {
	return beans.get(getPosition());
    }

    @Override
    public T getObjectAtPosition(int position) {
	checkArgument(position < getCount(), "Invalid requested position '" + position + "', as the cursor size is '" + getCount() + "'");
	return beans.get(position);
    }
}