org.eclipse.birt.report.model.api
Class GroupElementHandle

java.lang.Object
  extended by org.eclipse.birt.report.model.api.GroupElementHandle
Direct Known Subclasses:
EmptyGroupElementHandle, SimpleGroupElementHandle

public abstract class GroupElementHandle
extends java.lang.Object

This class provides services to deal with a group of elements. It is mostly useful for some multiple-selection cases, elements of the same type(or share the same base type) can be handled as a whole. User can perform some operations on the collection of elements.

For our ease-of-use purpose, we support multiple selections across type. Given a collection of elements, user can ask for their common properties(including user property definitions). Also, return a list of values that are identical for all items. Finally, return an indication of whether all elements are of the same type.

This class also supports a collection of elements contains some objects that are not a DesignElementHandle or its subclass. For this case, getCommonProperties always returns an empty list.

For BIRT UI usage, the attributes view will go blank if the providing elements are not of the same type, the property sheet will show the common properties(including user property definitions).

This handle is mutable, it can be kept. The query results changed as the given elements themselves changed.

Note that the Model special handling of the case where all elements are the same type: in this case, by definition, all BIRT-defined properties are the same. (User-defined properties may differ.)


Constructor Summary
GroupElementHandle()
          Default constructor.
 
Method Summary
protected abstract  boolean allExtendedElements()
          Checks if all elements have extends parents or virtual parents.
abstract  void clearLocalProperties()
          Clears values of all common properties(except the extends property) for the given collection of elements.
 void clearProperty(java.lang.String propName)
          Clears the value of a property on the given collection of elements if the property is a common property shared by each element.
abstract  java.util.List getCommonProperties()
          Returns the common properties shared by the given group of elements(including user properties).
 java.lang.String getDisplayProperty(java.lang.String propName)
          If the given property is a common property, value will be returned as a display value if all values within the group of elements are equal.
abstract  java.util.List getElements()
          Returns the list that contains the group of design elements.
 java.lang.String getLocalStringProperty(java.lang.String propName)
          If the given property is a common property, value will be returned as a string if all values within the group of elements are equal and one of them has a local value.
abstract  org.eclipse.birt.report.model.core.Module getModule()
          Returns the module.
abstract  ModuleHandle getModuleHandle()
          Returns the handle of module.
abstract  GroupPropertyHandle getPropertyHandle(java.lang.String propName)
          If property is shared by the group of elements, return the corresponding GroupPropertyHandle, otherwise, return null.
 java.lang.String getStringProperty(java.lang.String propName)
          If the given property is a common property, value will be returned as a string if all values within the group of elements are equal.
 boolean hasLocalPropertiesForExtendedElements()
          This method returnt true in following condition:
abstract  boolean isExtendedElements()
          Returns true if each of the given collection of element extends has a parent.
protected abstract  boolean isInGroup(DesignElementHandle element)
          Checks whether the element is a member of GroupElementHandle.
protected abstract  boolean isPropertyReadOnly(java.lang.String propName)
          Checks whether a property is read-only in the property sheet.
protected abstract  boolean isPropertyVisible(java.lang.String propName)
          Checks whether a property is visible in the property sheet.
abstract  boolean isSameType()
          Indicates that if the given elements are of the same definition.
 java.util.Iterator propertyIterator()
          Returns an iterator over the common properties.
 void setProperty(java.lang.String propName, java.lang.Object value)
          Set the value of a property on the given collection of elements.
 void setStringProperty(java.lang.String propName, java.lang.String value)
          Set the value of a property to a string .
 boolean shareSameValue(java.lang.String propName)
          Indicates whether the group of element share the same value for this property.
abstract  java.util.Iterator visiblePropertyIterator()
          Returns an iterator over the common properties that are visible.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

GroupElementHandle

public GroupElementHandle()
Default constructor.

Method Detail

getElements

public abstract java.util.List getElements()
Returns the list that contains the group of design elements. Contents of it is DesignElementHandle

Returns:
the list that contains the group of design elements.

getModule

public abstract org.eclipse.birt.report.model.core.Module getModule()
Returns the module.

Returns:
the module

getModuleHandle

public abstract ModuleHandle getModuleHandle()
Returns the handle of module.

Returns:
the handle of module

isSameType

public abstract boolean isSameType()
Indicates that if the given elements are of the same definition. Elements are considered of same type if their element definitions are identical.

If elements have different definitions. Even the same element type, the return value is false. For example, if the list contains an OdaDataSource and a OdaDataSource, this method returns false.

Returns:
true if the given elements are of the same type; return false if elements are of different element types, or the given list is empty, or the list contains any object that is not an instance of DesignElementHandle.

getCommonProperties

public abstract java.util.List getCommonProperties()
Returns the common properties shared by the given group of elements(including user properties). Contents of the list is element property definitions. If elements do not share any common property, return an empty list.

Returns:
the common properties shared by the given group of elements. If elements do not share any common property, or the given list is empty, or the list contains any item that is not an instance of DesignElementHandle, return an empty list.

propertyIterator

public final java.util.Iterator propertyIterator()
Returns an iterator over the common properties. Contents of the iterator are handles to the common properties, type of them is GroupPropertyHandle. Note: remove is not support for the iterator.

Returns:
an iterator over the common properties. Contents of the iterator are handles to the common properties, type of them is GroupPropertyHandle

visiblePropertyIterator

public abstract java.util.Iterator visiblePropertyIterator()
Returns an iterator over the common properties that are visible. Contents of the iterator are handles to the common properties, type of them is GroupPropertyHandle. Note: remove is not support for the iterator.

Returns:
an iterator over the common properties. Contents of the iterator are handles to the common properties, type of them is GroupPropertyHandle

isPropertyVisible

protected abstract boolean isPropertyVisible(java.lang.String propName)
Checks whether a property is visible in the property sheet. The visible property is visible in all elements.

Parameters:
propName - the property name
Returns:
true if it is visible. Otherwise false.

clearLocalProperties

public abstract void clearLocalProperties()
                                   throws SemanticException
Clears values of all common properties(except the extends property) for the given collection of elements. Clearing a property removes any value set for the property on this element. After this, the element will now inherit the property from its parent element, style, or from the default value for the property.

Throws:
SemanticException - if the property is not defined on this element

isExtendedElements

public abstract boolean isExtendedElements()
Returns true if each of the given collection of element extends has a parent. Returns false otherwise. If the collection has no elements, also return false

Returns:
true if each of the given collection of element extends has a parent. Returns false otherwise. If the collection has no elements, also return false

hasLocalPropertiesForExtendedElements

public final boolean hasLocalPropertiesForExtendedElements()
This method returnt true in following condition:

1. The multi selected elements are same type.

2. And the multi selected elements have extends.

3. If any of the given elements has local properties.

Returns:
true if the conditions is met.

allExtendedElements

protected abstract boolean allExtendedElements()
Checks if all elements have extends parents or virtual parents.

Returns:
true If all elements have extend parents or virtual parents. Otherwise false;

isPropertyReadOnly

protected abstract boolean isPropertyReadOnly(java.lang.String propName)
Checks whether a property is read-only in the property sheet. The visible property is read-only in all elements.

Parameters:
propName - the property name
Returns:
true if it is read-only. Otherwise false.

getPropertyHandle

public abstract GroupPropertyHandle getPropertyHandle(java.lang.String propName)
If property is shared by the group of elements, return the corresponding GroupPropertyHandle, otherwise, return null.

Parameters:
propName - name of the property needs to be handled.
Returns:
If the property is a common property among the elements, return the corresponding GroupPropertyHandle; Otherwise return null.

getStringProperty

public final java.lang.String getStringProperty(java.lang.String propName)
If the given property is a common property, value will be returned as a string if all values within the group of elements are equal. If the property is not a common property, return null.

Parameters:
propName - name of the property.
Returns:
the value as a string if the property is a common property and all the elements have the same value. Return null if the property is not a common property or elements have different values for this property.
See Also:
GroupPropertyHandle.getStringValue()

getDisplayProperty

public final java.lang.String getDisplayProperty(java.lang.String propName)
If the given property is a common property, value will be returned as a display value if all values within the group of elements are equal. If the property is not a common property, return null.

Parameters:
propName - name of the property.
Returns:
the value as a display value if the property is a common property and all the elements have the same value. Return null if the property is not a common property or elements have different values for this property.
See Also:
GroupPropertyHandle#getDisplayProperty()

getLocalStringProperty

public final java.lang.String getLocalStringProperty(java.lang.String propName)
If the given property is a common property, value will be returned as a string if all values within the group of elements are equal and one of them has a local value. If the property is not a common property or none of them has a local value, return null.

Parameters:
propName - name of the property.
Returns:
the value as a string if the property is a common property, all the elements have the same value and one of them has a local value. Return null if the property is not a common property or elements have different values for this property or none of them has a local value.
See Also:
GroupPropertyHandle.getLocalStringValue()

shareSameValue

public final boolean shareSameValue(java.lang.String propName)
Indicates whether the group of element share the same value for this property.

If all element has a null value for this property, it is considered that they share the same value.

Parameters:
propName - name of the property.
Returns:
true if the group of element share the same value. Return false if the property is not a common property or elements have different values for this property.

setProperty

public final void setProperty(java.lang.String propName,
                              java.lang.Object value)
                       throws SemanticException
Set the value of a property on the given collection of elements. If the property provided is not a common property then this method simply return; Otherwise, the value will be set on the group of elements.

Parameters:
propName - name of the property.
value - value needs to set.
Throws:
SemanticException - if the value is invalid for the property, or the property is undefined on the elements.
See Also:
GroupPropertyHandle.setValue(Object)

clearProperty

public final void clearProperty(java.lang.String propName)
                         throws SemanticException
Clears the value of a property on the given collection of elements if the property is a common property shared by each element. Clearing a property removes any value set for the property on this element. After this, the element will now inherit the property from its parent element, style, or from the default value for the property.

If the property provided is not a common property then this method simply return, else, the value will be cleared on the group of elements.

Parameters:
propName - the name of the property to clear.
Throws:
SemanticException - if the property is not defined on this element

setStringProperty

public final void setStringProperty(java.lang.String propName,
                                    java.lang.String value)
                             throws SemanticException
Set the value of a property to a string . If the property provided is not a common property then this method simply return; Else, the string value will be set on the group of element.

Parameters:
propName - name of the property.
value - value needs to set.
Throws:
SemanticException - if the value is invalid for the property, or the property is undefined on the elements.

isInGroup

protected abstract boolean isInGroup(DesignElementHandle element)
Checks whether the element is a member of GroupElementHandle.

Parameters:
element - the element to check
Returns:
true if the element is in the list, otherwise false.


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