mirror of https://github.com/DanilaFe/abacus
89 lines
2.8 KiB
Java
89 lines
2.8 KiB
Java
package org.nwapw.abacus.plugin;
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import org.nwapw.abacus.function.Function;
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import java.util.HashMap;
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/**
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* A plugin class that can be externally implemented and loaded via the
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* plugin manager. Plugins provide functionality to the calculator
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* with the "hasFunction" and "getFunction" functions,
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* and can use "registerFunction" and "functionFor" for
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* loading internally.
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*/
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public abstract class Plugin {
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/**
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* A hash map of functions mapped to their string names.
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*/
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private HashMap<String, Function> functions;
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/**
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* The plugin manager in which to search for functions
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* not inside this package,
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*/
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private PluginManager manager;
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private Plugin(){ }
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/**
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* Creates a new plugin with the given PluginManager.
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* @param manager the manager controlling this plugin.
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*/
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public Plugin(PluginManager manager) {
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this.manager = manager;
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functions = new HashMap<>();
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}
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/**
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* Determines whether the current plugin provides the given function name.
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* @param functionName the name of the function provided.
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* @return true of the function exists, false if it doesn't.
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*/
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public final boolean hasFunction(String functionName) {
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return functions.containsKey(functionName);
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}
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/**
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* Gets a function under the given function name.
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* @param functionName the name of the function to get
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* @return the function, or null if this plugin doesn't provide it.
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*/
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public final Function getFunction(String functionName) {
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return functions.get(functionName);
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}
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/**
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* To be used in load(). Registers a function abstract class with the
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* plugin internally, which makes it accessible to the plugin manager.
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* @param name the name to register by.
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* @param toRegister the function implementation.
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* @return true if the function was registered successfully, false if not.
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*/
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protected final boolean registerFunction(String name, Function toRegister) {
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if(functionFor(name) == null){
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functions.put(name, toRegister);
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return true;
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}
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return false;
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}
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/**
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* Searches the PluginManager for the given function name.
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* This can be used by the plugins internally in order to call functions
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* they do not provide.
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* @param name then name for which to search
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* @return the resulting function, or null if none was found for that name.
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*/
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protected final Function functionFor(String name) {
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return manager.functionFor(name);
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}
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/**
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* Abstract method to be overridden by plugin implementation, in which the plugins
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* are supposed to register the functions they provide and do any other
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* necessary setup.
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*/
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public abstract void load();
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}
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