com.google.api.ads.common.lib.utils.logging.LoggingModule Maven / Gradle / Ivy

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Client library for Java for accessing ads APIs including DFP. If you want to use this library, you must also include another Maven artifact to specify which framework you would like to use it with. For example, to use DFP with Axis, you should include the "dfp-axis" artifact.
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// Copyright 2011 Google Inc. All Rights Reserved.
//
// 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.api.ads.common.lib.utils.logging;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Supplier;
import com.google.inject.AbstractModule;
import com.google.inject.Provider;
import com.google.inject.TypeLiteral;
import com.google.inject.name.Names;
import javax.annotation.concurrent.ThreadSafe;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Module for logging.
 */
public class LoggingModule extends AbstractModule {

  private final String loggerPrefix;

  /**
   * Constructor.
   *
   * @param loggerPrefix the logger prefix.
   */
  public LoggingModule(String loggerPrefix) {
    this.loggerPrefix = loggerPrefix;
  }

  @Override
  protected void configure() {
    bind(AdsServiceLoggers.class);
    // DocumentBuilderFactory is *not* guaranteed to be thread-safe.
    bind(new TypeLiteral>(){}).to( 
        DocumentBuilderSupplier.class);
    // Transformer is *not* guaranteed to be thread-safe.
    bind(new TypeLiteral>(){}).to( 
        TransformerSupplier.class);
    // XPathFactory is *not* guaranteed to be thread-safe.
    bind(new TypeLiteral>(){}).to( 
        XPathSupplier.class);
    bind(PrettyPrinterInterface.class).to(PrettyPrinter.class);
    bind(Logger.class)
        .annotatedWith(Names.named("libLogger")).toInstance(AdsServiceLoggers.ADS_API_LIB_LOG);
    configureLogger(loggerPrefix, "soapXmlLogger");
    configureLogger(loggerPrefix, "requestInfoLogger");
  }

  protected void configureLogger(String prefix, String name) {
    bind(Logger.class).annotatedWith(Names.named(name)).toProvider(
        new LoggerProvider(prefix, name)).asEagerSingleton();
  }
 
  /**
   * Thread-safe supplier for {@link XPath} objects. This is necessary because
   * {@link XPathFactory} is not thread-safe.
   */
  @ThreadSafe
  private static final class XPathSupplier implements Supplier {
    @Override
    public XPath get() {
      return XPathFactory.newInstance().newXPath();
    }
  }

  /**
   * Thread-safe supplier for {@link DocumentBuilder} objects. This is necessary because {@link
   * DocumentBuilderFactory} is not thread-safe.
   */
  @ThreadSafe
  @VisibleForTesting
  static final class DocumentBuilderSupplier implements Supplier {
    @Override
    public DocumentBuilder get() {
      DocumentBuilderFactory factory;
      try {
        factory = DocumentBuilderFactory.newInstance();
      } catch (FactoryConfigurationError e) {
        AdsServiceLoggers.ADS_API_LIB_LOG.warn(
            "Unable to instantiate a DocumentBuilderFactory. Error: " + e);
        return null;
      }

      try {
        return factory.newDocumentBuilder();
      } catch (ParserConfigurationException e) {
        AdsServiceLoggers.ADS_API_LIB_LOG.warn(
            "Unable to obtain a new DocumentBuilder. Error: " + e);
        return null;
      }
    }
  }

  /**
   * Thread-safe supplier for {@link Transformer} objects. This is necessary because {@link
   * TransformerFactory} is not thread-safe.
   */
  @ThreadSafe
  @VisibleForTesting
  static final class TransformerSupplier implements Supplier {
    @Override
    public Transformer get() {
      TransformerFactory factory;
      try {
        factory = TransformerFactory.newInstance();
      } catch (TransformerFactoryConfigurationError e) {
        AdsServiceLoggers.ADS_API_LIB_LOG.warn(
            "Unable to instantiate a TransformerFactory. Error: ", e);
        return null;
      }

      Transformer transformer;
      try {
        transformer = factory.newTransformer();
      } catch (TransformerConfigurationException e) {
        AdsServiceLoggers.ADS_API_LIB_LOG.warn("Unable to obtain a new Transformer. Error: ", e);
        return null;
      }

      // An incorrectly implemented factory could return null.
      if (transformer == null) {
        AdsServiceLoggers.ADS_API_LIB_LOG.warn("TransformerFactory returned a null instance.");
        return null;
      }

      try {
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
      } catch (IllegalArgumentException e) {
        // Ignore this exception since it indicates that the transformer does not support indent or
        // indent amount. This will only affect log output formatting and is therefore non-critical.
        AdsServiceLoggers.ADS_API_LIB_LOG.debug(
            "[NON-CRITICAL] XML in log messages may not be indented properly because Transformer "
                + "implementation does not support one or more indent options.",
            e);
      }
      return transformer;
    }
  }

  /**
   * Provider for Loggers.
   */
  private static final class LoggerProvider implements Provider {

    private final String loggerPrefix;
    private final String logType;

    /**
     * Constructor.
     *
     * @param loggerPrefix the logger prefix
     * @param logType the log type (i.e. soap_xml)
     */
    public LoggerProvider(String loggerPrefix, String logType) {
      this.loggerPrefix = loggerPrefix;
      this.logType = logType;
    }

    @Override
    public Logger get() {
      return LoggerFactory.getLogger(loggerPrefix + "." + logType);
    }
  }
}