io.mapzone.controller.provision.ProvisionExecutor.java Source code

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Here is the source code for io.mapzone.controller.provision.ProvisionExecutor.java

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/* 
 * Copyright (C) 2015, the @authors. All rights reserved.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 3.0 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 */
package io.mapzone.controller.provision;

import io.mapzone.controller.provision.Provision.Status;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;

/**
 * Find a way to execute a given target {@link Provision}.
 *
 * @author <a href="http://www.polymap.de">Falko Brutigam</a>
 */
public abstract class ProvisionExecutor {

    protected ContextFactory contextFactory;

    protected Map<Pair<Class, String>, Object> contextValues;

    protected Class<? extends Provision>[] preliminaries;

    public ProvisionExecutor(Class<? extends Provision>[] preliminaries) {
        this.preliminaries = preliminaries;

        contextValues = new HashMap();
        contextFactory = new ContextFactory() {
            @Override
            protected void setValue(Class type, String scope, Object value) {
                if (value != null) {
                    contextValues.put(ImmutablePair.of(type, scope), value);
                } else {
                    contextValues.remove(ImmutablePair.of(type, scope));
                }
            }

            @Override
            protected Object getValue(Class type, String scope) {
                return contextValues.get(ImmutablePair.of(type, scope));
            }
        };
    }

    public Map<Pair<Class, String>, Object> getContextValues() {
        return contextValues;
    }

    public ProvisionExecutor setContextValues(Map<Pair<Class, String>, Object> contextValues) {
        this.contextValues = new HashMap(contextValues);
        return this;
    }

    public <T extends Provision> T newProvision(Class<T> type)
            throws InstantiationException, IllegalAccessException {
        T result = type.newInstance();
        contextFactory.inject(result);
        return result;
    }

    /**
     * Try to find a way to execute the given <code>target</code> together with the
     * given {@link #preliminaries}.
     */
    public abstract Status execute(Provision target) throws Exception;

    /**
     * Execute this very single Provision. Allows to intercept algorithm.
     */
    protected Status executeProvision(Provision provision) throws Exception {
        return provision.execute();
    }

}