ParseType.java

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package com.salesforce.apt.graph.types.impl;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.stream.Collectors;

public class ParseType {

  private final String type;
  private final List<ParseType> parameters = new ArrayList<>();

  public ParseType(String type) {
    this.type = type;
  }
  
  public ParseType(String type, ParseType... parameters) {
    this.type = type;
    this.parameters.addAll(Arrays.asList(parameters));
  }
  
  public String getType() {
    return type;
  }

  public List<ParseType> getParameters() {
    return parameters;
  }
  
  public static ParseType parse(String type) {
    final String parseToken = "*";
    String[] tokens = type
        .replaceAll("<", parseToken + "<" + parseToken)
        .replaceAll(">", parseToken + ">" + parseToken)
        .replaceAll(",", parseToken + "," + parseToken).split("\\" + parseToken);
    Queue<String> tokenQueue = new LinkedList<>(Arrays.asList(tokens).stream().map(t -> t.trim()).collect(Collectors.toList())); 
    return parseParameters(tokenQueue);
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + parameters.hashCode();
    result = prime * result + ((type == null) ? 0 : type.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (getClass() != obj.getClass()) {
      return false;
    }
    ParseType other = (ParseType)obj;
    if (!parameters.equals(other.parameters)) {
      return false;
    }
    if (type == null) {
      if (other.type != null) {
        return false;
      }
    } else {
      if (!type.equals(other.type)) {
        return false;
      }
    }
    return true;
  }

  @Override
  public String toString() {
    StringBuilder builder = new StringBuilder(getType());
    if (!getParameters().isEmpty()) {
      builder.append('<');
      Iterator<ParseType> iter = getParameters().iterator();
      while (iter.hasNext()) {
        builder.append(iter.next().toString());
        if (iter.hasNext()) {
          builder.append(',');
        }
      }
      builder.append('>');
    }
    return builder.toString();
  }

  private static ParseType parseParameters(Queue<String> tokens) {
    ParseType child = new ParseType(tokens.remove());
    if (tokens.isEmpty()) {
      return child;
    }
    if (",".equals(tokens.peek())) {
      return child;
    }
    if ("<".equals(tokens.peek())) {
      tokens.remove();
      child.parameters.add(parseParameters(tokens));
      while (",".equals(tokens.peek())) {
        tokens.remove();
        child.parameters.add(parseParameters(tokens));
      }
      if (">".equals(tokens.peek())) {
        tokens.remove();
      }
    }
    return child;
  }
    
}