org.eclipse.xtext.util.formallang.ProductionStringFactory.java Source code

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Here is the source code for org.eclipse.xtext.util.formallang.ProductionStringFactory.java

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/*******************************************************************************
 * Copyright (c) 2011 itemis AG (http://www.itemis.eu) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package org.eclipse.xtext.util.formallang;

import java.util.Collections;
import java.util.List;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Predicates;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;

/**
 * @author Moritz Eysholdt - Initial contribution and API
 */
public class ProductionStringFactory<TOKEN> implements ProductionFactory<String, TOKEN> {

    protected Function<TOKEN, String> token2String;

    public ProductionStringFactory() {
    }

    public ProductionStringFactory(Function<TOKEN, String> token2String) {
        super();
        this.token2String = token2String;
    }

    protected String card(boolean many, boolean optional) {
        return many ? (optional ? "*" : "+") : (optional ? "?" : "");
    }

    @Override
    public String createForAlternativeChildren(boolean many, boolean optional, Iterable<String> children) {
        List<String> childrenSorted = Lists.newArrayList(Iterables.filter(children, Predicates.notNull()));
        Collections.sort(childrenSorted);
        return "(" + Joiner.on(" | ").join(childrenSorted) + ")" + card(many, optional);
    }

    @Override
    public String createForSequentialChildren(boolean many, boolean optional, Iterable<String> children) {
        children = Iterables.filter(children, Predicates.notNull());
        if (many || optional)
            return "(" + Joiner.on(" ").join(children) + ")" + card(many, optional);
        return Joiner.on(" ").join(children) + card(many, optional);
    }

    @Override
    public String createForToken(boolean many, boolean optional, TOKEN token) {
        if (token2String != null)
            return token2String.apply(token) + card(many, optional);
        if (token == null)
            return "null" + card(many, optional);
        return token.toString() + card(many, optional);
    }

    @Override
    public String createForUnordertedChildren(boolean many, boolean optional, Iterable<String> children) {
        List<String> childrenSorted = Lists.newArrayList(Iterables.filter(children, Predicates.notNull()));
        Collections.sort(childrenSorted);
        return "(" + Joiner.on(" & ").join(childrenSorted) + ")" + card(many, optional);
    }

}