MaximumPriceFilterFactory.java

package com.manning.hsia.dvdstore.action.filter;

import org.apache.lucene.search.Filter;
import org.apache.lucene.search.RangeFilter;
import org.hibernate.search.annotations.Factory;
import org.hibernate.search.annotations.Key;
import org.hibernate.search.filter.FilterKey;
import org.hibernate.search.filter.StandardFilterKey;

/**
 * Example 8.10
 */
public class MaximumPriceFilterFactory {
	private static int PAD = 10;
	private long maxPrice = -1;
	
	public void setMaxPrice(long maxPrice) {  //inject max price
		this.maxPrice = maxPrice;
	}
	
	@Factory
	public Filter getMaximumPriceFilter() {
		if ( maxPrice == -1) {
			throw new IllegalStateException("MaximumPriceFilterFactory.maxPrice is mandatory");
		}
		Filter filter = RangeFilter.Less("price", pad(maxPrice) );  //build a range filter
		return filter;
	}
	
	@Key
	public FilterKey getKey() {
		StandardFilterKey key = new StandardFilterKey();
		key.addParameter(maxPrice);
		return key;
	}
	
	private String pad(long price) {  //apply same padding strategy as bridge
		String rawLong = Long.toString(price);
		if (rawLong.length() > PAD) 
			throw new IllegalArgumentException( "Try to pad on a number too big" );
		
		StringBuilder paddedLong = new StringBuilder( );
		for ( int padIndex = rawLong.length() ; padIndex < PAD ; padIndex++ ) {
			paddedLong.append('0');
		}
		return paddedLong.append( rawLong ).toString();
	}
}