MapData.java

//: net/mindview/util/MapData.java
// A Map filled with data using a generator object.
package thinkinginjava.typeinfo;

import java.util.LinkedHashMap;

import thinkinginjava.util.Generator;

public class MapData<K, V> extends LinkedHashMap<K, V> {
	// A single Pair Generator:
	public MapData(Generator<Pair<K, V>> gen, int quantity) {
		for (int i = 0; i < quantity; i++) {
			Pair<K, V> p = gen.next();
			put(p.key, p.value);
		}
	}

	// Two separate Generators:
	public MapData(Generator<K> genK, Generator<V> genV, int quantity) {
		for (int i = 0; i < quantity; i++) {
			put(genK.next(), genV.next());
		}
	}

	// A key Generator and a single value:
	public MapData(Generator<K> genK, V value, int quantity) {
		for (int i = 0; i < quantity; i++) {
			put(genK.next(), value);
		}
	}

	// An Iterable and a value Generator:
	public MapData(Iterable<K> genK, Generator<V> genV) {
		for (K key : genK) {
			put(key, genV.next());
		}
	}

	// An Iterable and a single value:
	public MapData(Iterable<K> genK, V value) {
		for (K key : genK) {
			put(key, value);
		}
	}

	// Generic convenience methods:
	public static <K, V> MapData<K, V> map(Generator<Pair<K, V>> gen,
			int quantity) {
		return new MapData<K, V>(gen, quantity);
	}

	public static <K, V> MapData<K, V> map(Generator<K> genK,
			Generator<V> genV, int quantity) {
		return new MapData<K, V>(genK, genV, quantity);
	}

	public static <K, V> MapData<K, V> map(Generator<K> genK, V value,
			int quantity) {
		return new MapData<K, V>(genK, value, quantity);
	}

	public static <K, V> MapData<K, V> map(Iterable<K> genK, Generator<V> genV) {
		return new MapData<K, V>(genK, genV);
	}

	// 目的是将所有这些key加入到map中，同时value值置为0
	public static <K, V> MapData<K, V> map(Iterable<K> genK, V value) {
		return new MapData<K, V>(genK, value);
	}
} // /:~