org.gcube.resources.discovery.client.queries.impl
Class QueryTemplate

java.lang.Object
  org.gcube.resources.discovery.client.queries.impl.QueryBox
      org.gcube.resources.discovery.client.queries.impl.QueryTemplate

All Implemented Interfaces:

Query

Direct Known Subclasses:

XQuery

public class QueryTemplate
extends QueryBox
implements Query

A Query that interpolates named parameters inside a template.

Templates are strings with empty XML elements, optionally with a DEFAULT attribute, e.g.:

all results that satisfy <cond1/> or <cond2 def='that'/> <extra/>

Whenever expression() is invoked, the elements in the template are replaced according to the first rule that applies among the following:

• by the value of an equally named parameter, if one exists
• by the value of the DEFAULT attribute, if one exists
• by the empty string

For example, given the previous template and the single parameter cond1="this", expression() returns:

all results that satisfy this or that

Field Summary

static String

DEFAULT

Constructor Summary

QueryTemplate(String template)
Creates an instance with a template.

QueryTemplate(String template, Map<String,String> parameters)
Creates an instance with a template and an initial set of parameters.

Method Summary

void	addParameter(String name, String value) Adds a parameter to the query, overwriting any value that it may already have.
void	appendParameter(String name, String value) Adds a parameter to the query, extending any value that it may already have.
String	expression() Returns the textual expression of the query.
boolean	hasParameter(String name) Returns true if the query has a given parameter.
String	parameter(String name) Returns the current value of a parameter.

Methods inherited from class org.gcube.resources.discovery.client.queries.impl.QueryBox

equals, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT

public static final String DEFAULT

See Also:

Constant Field Values

Constructor Detail

QueryTemplate

public QueryTemplate(String template)

Creates an instance with a template.

Parameters:

template - the template

QueryTemplate

public QueryTemplate(String template,
                     Map<String,String> parameters)

Creates an instance with a template and an initial set of parameters.

Parameters:

template - the template

Method Detail

expression

public String expression()

Description copied from interface: Query

Returns the textual expression of the query.

Specified by:

expression in interface Query

Overrides:

expression in class QueryBox

Returns:

the expression.

addParameter

public void addParameter(String name,
                         String value)

Adds a parameter to the query, overwriting any value that it may already have.

Parameters:

name - the parameter name

value - the parameter value

Throws:

IllegalStateException - if the parameter name or value are null

appendParameter

public void appendParameter(String name,
                            String value)

Adds a parameter to the query, extending any value that it may already have.

Parameters:

name - the parameter name

value - the value

Throws:

IllegalStateException - if the parameter name or value are null

parameter

public String parameter(String name)
                 throws IllegalStateException

Returns the current value of a parameter.

Parameters:

name - the parameter name

Returns:

the value

Throws:

IllegalStateException - if the parameter does not exist

IllegalStateException - if the parameter name is null

hasParameter

public boolean hasParameter(String name)

Returns true if the query has a given parameter.

Parameters:

name - the parameter name

Returns:

true if the query has a given parameter, false otherwise

Throws:

IllegalStateException - if the parameter name is null