ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/WrappedIntHashMap.java

package com.comphenix.protocol.wrappers;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import javax.annotation.Nonnull;

import com.comphenix.protocol.reflect.FuzzyReflection;
import com.comphenix.protocol.reflect.fuzzy.FuzzyMethodContract;
import com.comphenix.protocol.utility.MinecraftReflection;
import com.google.common.base.Preconditions;

/**
 * Represents a wrapper for the internal IntHashMap in Minecraft.
 * @author Kristian
 * @deprecated IntHashMap no longer exists
 */
@Deprecated
public class WrappedIntHashMap extends AbstractWrapper {
    private static Method PUT_METHOD;
    private static Method GET_METHOD;
    private static Method REMOVE_METHOD;
    
    /**
     * Construct an IntHashMap wrapper around an instance.
     * @param handle - the NMS instance.
     */
    private WrappedIntHashMap(Object handle) {      
        super(MinecraftReflection.getIntHashMapClass());
        setHandle(handle);
    }
    
    /**
     * Construct a new IntHashMap.
     * @return A new IntHashMap.
     */
    public static WrappedIntHashMap newMap() {
        try {
            return new WrappedIntHashMap(MinecraftReflection.getIntHashMapClass().newInstance());
        } catch (Exception e) {
            throw new RuntimeException("Unable to construct IntHashMap.", e);
        }
    }
    
    /**
     * Construct a wrapper around a given NMS IntHashMap.
     * @param handle - the NMS IntHashMap.
     * @return The created wrapped.
     * @throws IllegalArgumentException If the handle is not an IntHasMap.
     */
    public static WrappedIntHashMap fromHandle(@Nonnull Object handle) {
        return new WrappedIntHashMap(handle);
    }
    
    /**
     * Associates a specified key with the given value in the integer map. 
     * <p>
     * If the key has already been associated with a value, then it will be replaced by the new value.
     * @param key - the key to insert.
     * @param value - the value to insert. Cannot be NULL.
     * @throws RuntimeException If the reflection machinery failed.
     */
    public void put(int key, Object value) {
        Preconditions.checkNotNull(value, "value cannot be NULL.");
        
        initializePutMethod();
        putInternal(key, value);
    }
    
    /**
     * Invoked when a value must be inserted into the underlying map, regardless of preconditions.
     * @param key - the key.
     * @param value - the value to insert.
     */
    private void putInternal(int key, Object value) {
        invokeMethod(PUT_METHOD, key, value);
    }
    
    /**
     * Retrieve the value associated with a specific key, or NULL if not found.
     * @param key - the integer key.
     * @return The associated value, or NULL.
     */
    public Object get(int key) {
        initializeGetMethod();
        return invokeMethod(GET_METHOD, key);
    }
        
    /**
     * Remove a mapping of a key to a value if it is present.
     * @param key - the key of the mapping to remove.
     * @return The object that was removed, or NULL if the key is not present.
     */
    public Object remove(int key) {
        initializeGetMethod();
        
        if (REMOVE_METHOD == null)
            return removeFallback(key);
        return invokeMethod(REMOVE_METHOD, key);
    }
    
    /**
     * Remove a entry in the IntHashMap using a fallback method.
     * @param key - the key of the mapping to remove.
     * @return The removed element.
     */
    private Object removeFallback(int key) {
        Object old = get(key);
        
        invokeMethod(PUT_METHOD, key, null);
        return old;
    }
    
    /**
     * Invoke a particular method on the current handle
     * @param method - the current method.
     * @param params - parameters.
     * @return The return value, if any.
     */
    private Object invokeMethod(Method method, Object... params) {
        try {
            return method.invoke(handle, params);
        } catch (IllegalArgumentException e) {
            throw new RuntimeException("Illegal argument.", e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException("Cannot access method.", e);
        } catch (InvocationTargetException e) {
            throw new RuntimeException("Unable to invoke " + method + " on " + handle, e);
        }
    }
    
    private void initializePutMethod() {
        if (PUT_METHOD == null) {
            // Fairly straight forward
            PUT_METHOD = FuzzyReflection.fromClass(MinecraftReflection.getIntHashMapClass()).getMethod(
                FuzzyMethodContract.newBuilder().
                    banModifier(Modifier.STATIC).
                    parameterCount(2).
                    parameterExactType(int.class).
                    parameterExactType(Object.class).
                    build());
        }
    }
    
    private void initializeGetMethod() {
        if (GET_METHOD == null) {
            WrappedIntHashMap temp = WrappedIntHashMap.newMap();
            String expected = "hello";
                    
            // Determine which method to trust
            for (Method method : FuzzyReflection.fromClass(MinecraftReflection.getIntHashMapClass()).
                    getMethodListByParameters(Object.class, new Class<?>[] { int.class })) {
                
                // Initialize a value
                temp.put(1, expected);
                
                // Skip static methods
                if (Modifier.isStatic(method.getModifiers()))
                    continue;
                
                try {
                    boolean first = expected.equals(method.invoke(temp.getHandle(), 1));
                    boolean second = expected.equals(method.invoke(temp.getHandle(), 1));
                    
                    // See if we found the method we are looking for
                    if (first && !second) {
                        REMOVE_METHOD = method;
                    } else if (first && second) {
                        GET_METHOD = method;
                    }
                } catch (Exception e) {
                    // Suppress
                }
            }
            
            if (GET_METHOD == null)
                throw new IllegalStateException("Unable to find appropriate GET_METHOD for IntHashMap.");
        }
    }
}