com.github.mustachejava.reflect.GuardedBinding Maven / Gradle / Ivy

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package com.github.mustachejava.reflect;

import com.github.mustachejava.Binding;
import com.github.mustachejava.Code;
import com.github.mustachejava.MustacheException;
import com.github.mustachejava.ObjectHandler;
import com.github.mustachejava.TemplateContext;
import com.github.mustachejava.codes.PartialCode;
import com.github.mustachejava.util.GuardException;
import com.github.mustachejava.util.Wrapper;

import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.logging.Logger;

import static java.util.Collections.singletonList;

/**
 * Codes are bound to their variables through bindings.
 *
 * User: sam
 * Date: 7/7/12
 * Time: 6:05 PM
 */
public class GuardedBinding implements Binding {
  // Debug callsites
  private static Logger logger = Logger.getLogger("mustache");
  private static boolean debug = Boolean.getBoolean("mustache.debug");

  private final ObjectHandler oh;
  private final TemplateContext tc;
  private final String name;
  private final Code code;

  public GuardedBinding(ObjectHandler oh, String name, TemplateContext tc, Code code) {
    this.name = name;
    this.code = code;
    this.oh = oh;
    this.tc = tc;
  }

  /**
   * The chances of a new guard every time is very low. Instead we will
   * store previously used guards and try them all before creating a new one.
   */
  private Set previousSet = new CopyOnWriteArraySet<>();
  private volatile Wrapper[] prevWrappers;

  /**
   * Retrieve the first value in the stacks of scopes that matches
   * the give name. The method wrappers are cached and guarded against
   * the type or number of scopes changing.
   *
   * Methods will be found using the object handler, called here with
   * another lookup on a guard failure and finally coerced to a final
   * value based on the ObjectHandler you provide.
   *
   * @param scopes An array of scopes to interrogate from right to left.
   * @return The value of the field or method
   */
  @Override
  public Object get(List