com.google.gwt.dev.generator.NameFactory.java Source code

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Here is the source code for com.google.gwt.dev.generator.NameFactory.java

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/*
 * Copyright 2007 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.dev.generator;

import java.util.Set;
import java.util.HashSet;
import java.util.Collection;

/**
 * Generates unqiue identifiers. Use this class to avoid generating conflicting
 * names with user code. This class isn't smart enough to know about scopes
 * (which isn't generally a problem for generators in any case).
 */
public class NameFactory {

    private final Set<String> usedNames = new HashSet<String>();

    /**
     * Creates a new <code>NameFactory</code> that knows about
     * <code>existingNames</code>.
     * 
     * @param existingNames a list of names that may be <code>null</code>.
     */
    public NameFactory(Collection<String> existingNames) {
        if (existingNames == null) {
            return;
        }
        usedNames.addAll(existingNames);
    }

    /**
     * Creates a new <code>NameFactory</code> that doesn't know about any
     * existing names.
     */
    public NameFactory() {
        this(null);
    }

    /**
     * Reserves a known name.  Asserts that the name is not already in this set.
     * 
     * @param name a not <code>null</code> name
     */
    public void addName(String name) {
        assert !usedNames.contains(name);
        usedNames.add(name);
    }

    /**
     * Creates a new unique name based off of <code>name</code> and adds it to
     * the list of known names.
     * 
     * @param name a not <code>null</code> name to base the new unique name from
     * @return a new unique, not <code>null</code> name. This name may be
     *         possibly identical to <code>name</code>.
     */
    public String createName(String name) {
        String newName = name;

        for (int count = 0; true; ++count) {
            if (usedNames.contains(newName)) {
                newName = name + count;
            } else {
                usedNames.add(newName);
                return newName;
            }
        }
    }
}