org.opencms.loader
Class CmsImageLoader

java.lang.Object
  org.opencms.loader.CmsDumpLoader
      org.opencms.loader.CmsImageLoader

All Implemented Interfaces:

I_CmsConfigurationParameterHandler, I_CmsResourceLoader, I_CmsEventListener

public class CmsImageLoader
extends CmsDumpLoader
implements I_CmsEventListener

Loader for images from the OpenCms VSF with integrated image scaling and processing capabilities.

To scale or process an image, the parameter CmsImageScaler.PARAM_SCALE has to be appended to the image URI. The value for the parameter needs to be composed from the SCALE_PARAM options provided by the constants in the CmsResourceTypeImage class.

For example, to scale an image to exact 800x600 pixel with center fitting and a background color of grey, the following parameter String can be used: w:800,h:600,t:0,c:c0c0c0.

Since:

6.2.0

Version:

$Revision: 1.14 $

Author:

Alexander Kandzior

Field Summary

static java.lang.String	CONFIGURATION_DOWNSCALE The configuration parameter for the OpenCms XML configuration to set the image down scale operation.
static java.lang.String	CONFIGURATION_IMAGE_FOLDER The configuration parameter for the OpenCms XML configuration to set the image cache repository.
static java.lang.String	CONFIGURATION_MAX_BLUR_SIZE The configuration parameter for the OpenCms XML configuration to set the maximum image blur size.
static java.lang.String	CONFIGURATION_MAX_SCALE_SIZE The configuration parameter for the OpenCms XML configuration to set the maximum image scale size.
static java.lang.String	CONFIGURATION_SCALING_ENABLED The configuration parameter for the OpenCms XML configuration to enable the image scaling.
static java.lang.String	IMAGE_REPOSITORY_DEFAULT Default name for the image cache repository.
protected static org.apache.commons.logging.Log	LOG The log object for this class.
protected static java.lang.String	m_downScaleParams The (optional) image down scale parameters for image write operations.
protected static boolean	m_enabled Indicates if image scaling is active.
protected java.lang.String	m_imageRepositoryFolder The name of the configured image cache repository.
protected static int	m_maxBlurSize The maximum image size (width * height) to apply image blurring when down scaling (setting this to high may cause "out of memory" errors).
protected int	m_maxScaleSize The maximum image size (width or height) to allow when up scaling an image using request parameters.
protected static CmsVfsNameBasedDiskCache	m_vfsDiskCache The disk cache to use for saving scaled image versions.
static java.lang.String	PARAM_CLEAR_IMAGES_CACHE Clear event parameter.
static int	RESOURCE_LOADER_ID_IMAGE_LOADER The id of this loader.

Fields inherited from class org.opencms.loader.CmsDumpLoader

RESOURCE_LOADER_ID

Fields inherited from interface org.opencms.main.I_CmsEventListener

EVENT_BEFORE_PUBLISH_PROJECT, EVENT_CLEAR_CACHES, EVENT_CLEAR_OFFLINE_CACHES, EVENT_CLEAR_ONLINE_CACHES, EVENT_CLEAR_PRINCIPAL_CACHES, EVENT_FLEX_CACHE_CLEAR, EVENT_FLEX_PURGE_JSP_REPOSITORY, EVENT_FULLSTATIC_EXPORT, EVENT_GROUP_MODIFIED, EVENT_LOGIN_USER, EVENT_OU_MODIFIED, EVENT_PROJECT_MODIFIED, EVENT_PROPERTY_DEFINITION_CREATED, EVENT_PROPERTY_DEFINITION_MODIFIED, EVENT_PROPERTY_MODIFIED, EVENT_PUBLISH_PROJECT, EVENT_REBUILD_SEARCHINDEXES, EVENT_RESOURCE_AND_PROPERTIES_MODIFIED, EVENT_RESOURCE_COPIED, EVENT_RESOURCE_CREATED, EVENT_RESOURCE_DELETED, EVENT_RESOURCE_MODIFIED, EVENT_RESOURCE_MOVED, EVENT_RESOURCES_AND_PROPERTIES_MODIFIED, EVENT_RESOURCES_MODIFIED, EVENT_UPDATE_EXPORTS, EVENT_USER_MODIFIED, KEY_CHANGE, KEY_DBCONTEXT, KEY_GROUP_ID, KEY_GROUP_NAME, KEY_INDEX_NAMES, KEY_OU_ID, KEY_OU_NAME, KEY_PROJECTID, KEY_PUBLISHID, KEY_PUBLISHLIST, KEY_REPORT, KEY_RESOURCE, KEY_RESOURCES, KEY_USER_ACTION, KEY_USER_ID, KEY_USER_NAME, LISTENERS_FOR_ALL_EVENTS, VALUE_GROUP_MODIFIED_ACTION_CREATE, VALUE_GROUP_MODIFIED_ACTION_DELETE, VALUE_GROUP_MODIFIED_ACTION_WRITE, VALUE_OU_MODIFIED_ACTION_CREATE, VALUE_OU_MODIFIED_ACTION_DELETE, VALUE_USER_MODIFIED_ACTION_ADD_USER_TO_GROUP, VALUE_USER_MODIFIED_ACTION_CREATE_USER, VALUE_USER_MODIFIED_ACTION_DELETE_USER, VALUE_USER_MODIFIED_ACTION_REMOVE_USER_FROM_GROUP, VALUE_USER_MODIFIED_ACTION_RESET_PASSWORD, VALUE_USER_MODIFIED_ACTION_SET_OU, VALUE_USER_MODIFIED_ACTION_WRITE_USER

Fields inherited from interface org.opencms.loader.I_CmsResourceLoader

PARAMETER_ELEMENT

Fields inherited from interface org.opencms.configuration.I_CmsConfigurationParameterHandler

ADD_PARAMETER_METHOD, INIT_CONFIGURATION_METHOD

Constructor Summary

CmsImageLoader()
Creates a new image loader.

Method Summary

void	addConfigurationParameter(java.lang.String paramName, java.lang.String paramValue) Adds a configuration parameter to this parameter configurable class instance.
void	cmsEvent(CmsEvent event) Acknowledge the occurrence of the specified event, implement this method to check for CmsEvents in your class.
void	destroy() Destroy this ResourceLoder, this is a NOOP so far.
java.util.Map	getConfiguration() Will always return null since this loader does not need to be configured.
static java.lang.String	getDownScaleParams() Returns the image down scale parameters, which is set with the CONFIGURATION_DOWNSCALE configuration option.
static java.lang.String	getImageRepositoryPath() Returns the path of the image cache repository folder in the RFS, which is set with the CONFIGURATION_IMAGE_FOLDER configuration option.
int	getLoaderId() Returns the id of the ResourceLoader.
static int	getMaxBlurSize() The maximum blur size for image re-scale operations, which is set with the CONFIGURATION_MAX_BLUR_SIZE configuration option.
protected CmsFile	getScaledImage(CmsObject cms, CmsResource resource, CmsImageScaler scaler) Returns a scaled version of the given OpenCms VFS image resource.
void	initConfiguration() Initializes a configuration after all parameters have been added.
static boolean	isEnabled() Returns true if the image scaling and processing capabilities for the OpenCms VFS images have been enabled, false if not.
void	load(CmsObject cms, CmsResource resource, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) Basic top-page processing method for a I_CmsResourceLoader, this method is called if the page is called as a sub-element on a page not already loaded with a I_CmsResourceLoader.

Methods inherited from class org.opencms.loader.CmsDumpLoader

canSendLastModifiedHeader, dump, export, getResourceLoaderInfo, isStaticExportEnabled, isStaticExportProcessable, isUsableForTemplates, isUsingUriWhenLoadingTemplate, service

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CONFIGURATION_DOWNSCALE

public static final java.lang.String CONFIGURATION_DOWNSCALE

The configuration parameter for the OpenCms XML configuration to set the image down scale operation.

See Also:

Constant Field Values

CONFIGURATION_IMAGE_FOLDER

public static final java.lang.String CONFIGURATION_IMAGE_FOLDER

The configuration parameter for the OpenCms XML configuration to set the image cache repository.

See Also:

Constant Field Values

CONFIGURATION_MAX_BLUR_SIZE

public static final java.lang.String CONFIGURATION_MAX_BLUR_SIZE

The configuration parameter for the OpenCms XML configuration to set the maximum image blur size.

See Also:

Constant Field Values

CONFIGURATION_MAX_SCALE_SIZE

public static final java.lang.String CONFIGURATION_MAX_SCALE_SIZE

The configuration parameter for the OpenCms XML configuration to set the maximum image scale size.

See Also:

Constant Field Values

CONFIGURATION_SCALING_ENABLED

public static final java.lang.String CONFIGURATION_SCALING_ENABLED

The configuration parameter for the OpenCms XML configuration to enable the image scaling.

See Also:

Constant Field Values

IMAGE_REPOSITORY_DEFAULT

public static final java.lang.String IMAGE_REPOSITORY_DEFAULT

Default name for the image cache repository.

See Also:

Constant Field Values

PARAM_CLEAR_IMAGES_CACHE

public static final java.lang.String PARAM_CLEAR_IMAGES_CACHE

Clear event parameter.

See Also:

Constant Field Values

RESOURCE_LOADER_ID_IMAGE_LOADER

public static final int RESOURCE_LOADER_ID_IMAGE_LOADER

The id of this loader.

See Also:

Constant Field Values

LOG

protected static final org.apache.commons.logging.Log LOG

The log object for this class.

m_downScaleParams

protected static java.lang.String m_downScaleParams

The (optional) image down scale parameters for image write operations.

m_enabled

protected static boolean m_enabled

Indicates if image scaling is active.

m_maxBlurSize

protected static int m_maxBlurSize

The maximum image size (width * height) to apply image blurring when down scaling (setting this to high may cause "out of memory" errors).

m_vfsDiskCache

protected static CmsVfsNameBasedDiskCache m_vfsDiskCache

The disk cache to use for saving scaled image versions.

m_imageRepositoryFolder

protected java.lang.String m_imageRepositoryFolder

The name of the configured image cache repository.

m_maxScaleSize

protected int m_maxScaleSize

The maximum image size (width or height) to allow when up scaling an image using request parameters.

Constructor Detail

CmsImageLoader

public CmsImageLoader()

Creates a new image loader.

Method Detail

getDownScaleParams

public static java.lang.String getDownScaleParams()

Returns the image down scale parameters, which is set with the CONFIGURATION_DOWNSCALE configuration option.

If no down scale parameters have been set in the configuration, this will return null.

Returns:

the image down scale parameters

getImageRepositoryPath

public static java.lang.String getImageRepositoryPath()

Returns the path of the image cache repository folder in the RFS, which is set with the CONFIGURATION_IMAGE_FOLDER configuration option.

Returns:

the path of the image cache repository folder in the RFS

getMaxBlurSize

public static int getMaxBlurSize()

The maximum blur size for image re-scale operations, which is set with the CONFIGURATION_MAX_BLUR_SIZE configuration option.

The default is 2500 * 2500 pixel.

Returns:

the maximum blur size for image re-scale operations

isEnabled

public static boolean isEnabled()

Returns true if the image scaling and processing capabilities for the OpenCms VFS images have been enabled, false if not.

Image scaling is enabled by setting the loader parameter image.scaling.enabled to the value true in the configuration file opencms-vfs.xml.

Enabling image processing in OpenCms may require several additional configuration steps on the server running OpenCms, especially in UNIX systems. Here it is often required to have an X window server configured and accessible so that the required Java ImageIO operations work. Therefore the image scaling capabilities in OpenCms are disabled by default.

Returns:

true if the image scaling and processing capabilities for the OpenCms VFS images have been enabled

addConfigurationParameter

public void addConfigurationParameter(java.lang.String paramName,
                                      java.lang.String paramValue)

Description copied from interface: I_CmsConfigurationParameterHandler

Adds a configuration parameter to this parameter configurable class instance.

Specified by:

addConfigurationParameter in interface I_CmsConfigurationParameterHandler

Overrides:

addConfigurationParameter in class CmsDumpLoader

Parameters:

paramName - the name of the parameter

paramValue - the value for the parameter

See Also:

I_CmsConfigurationParameterHandler.addConfigurationParameter(java.lang.String, java.lang.String)

cmsEvent

public void cmsEvent(CmsEvent event)

Description copied from interface: I_CmsEventListener

Acknowledge the occurrence of the specified event, implement this method to check for CmsEvents in your class.

Specified by:

cmsEvent in interface I_CmsEventListener

Parameters:

event - CmsEvent that has occurred

See Also:

I_CmsEventListener.cmsEvent(org.opencms.main.CmsEvent)

destroy

public void destroy()

Description copied from class: CmsDumpLoader

Destroy this ResourceLoder, this is a NOOP so far.

Specified by:

destroy in interface I_CmsResourceLoader

Overrides:

destroy in class CmsDumpLoader

See Also:

I_CmsResourceLoader.destroy()

getConfiguration

public java.util.Map getConfiguration()

Description copied from class: CmsDumpLoader

Will always return null since this loader does not need to be configured.

Specified by:

getConfiguration in interface I_CmsConfigurationParameterHandler

Overrides:

getConfiguration in class CmsDumpLoader

Returns:

the configuration of this resource loader, or null

See Also:

I_CmsConfigurationParameterHandler.getConfiguration()

getLoaderId

public int getLoaderId()

Description copied from interface: I_CmsResourceLoader

Returns the id of the ResourceLoader.

Specified by:

getLoaderId in interface I_CmsResourceLoader

Overrides:

getLoaderId in class CmsDumpLoader

Returns:

the id of the ResourceLoader

See Also:

I_CmsResourceLoader.getLoaderId()

initConfiguration

public void initConfiguration()

Description copied from interface: I_CmsConfigurationParameterHandler

Initializes a configuration after all parameters have been added.

Specified by:

initConfiguration in interface I_CmsConfigurationParameterHandler

Overrides:

initConfiguration in class CmsDumpLoader

See Also:

I_CmsConfigurationParameterHandler.initConfiguration()

load

public void load(CmsObject cms,
                 CmsResource resource,
                 javax.servlet.http.HttpServletRequest req,
                 javax.servlet.http.HttpServletResponse res)
          throws java.io.IOException,
                 CmsException

Description copied from interface: I_CmsResourceLoader

Basic top-page processing method for a I_CmsResourceLoader, this method is called if the page is called as a sub-element on a page not already loaded with a I_CmsResourceLoader.

Specified by:

load in interface I_CmsResourceLoader

Overrides:

load in class CmsDumpLoader

Parameters:

cms - the initialized CmsObject which provides user permissions

resource - the requested OpenCms VFS resource

req - the servlet request

res - the servlet response

Throws:

java.io.IOException - might be thrown by the servlet environment

CmsException - in case of errors accessing OpenCms functions

See Also:

I_CmsResourceLoader.load(org.opencms.file.CmsObject, org.opencms.file.CmsResource, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

getScaledImage

protected CmsFile getScaledImage(CmsObject cms,
                                 CmsResource resource,
                                 CmsImageScaler scaler)
                          throws java.io.IOException,
                                 CmsException

Returns a scaled version of the given OpenCms VFS image resource.

All results are cached in disk. If the scaled version does not exist in the cache, it is created. Unscaled versions of the images are also stored in the cache.

Parameters:

cms - the current users OpenCms context

resource - the base VFS resource for the image

scaler - the configured image scaler

Returns:

a scaled version of the given OpenCms VFS image resource

Throws:

java.io.IOException - in case of errors accessing the disk based cache

CmsException - in case of errors accessing the OpenCms VFS