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ARQ is a SPARQL 1.1 query engine for Apache Jena
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.jena.sparql.util ;
import java.util.* ;
import java.util.concurrent.ConcurrentHashMap ;
import org.apache.jena.atlas.lib.Callback ;
import org.apache.jena.atlas.lib.Lib ;
import org.apache.jena.query.ARQ ;
import org.apache.jena.sparql.ARQConstants ;
import org.apache.jena.sparql.ARQException ;
import org.apache.jena.sparql.core.DatasetGraph ;
/**
* A class for setting and keeping named values. Used to pass
* implementation-specific parameters across general interfaces.
*/
public class Context {
public static final Context emptyContext = new Context(true) ;
protected Map context = new ConcurrentHashMap<>() ;
protected List> callbacks = new ArrayList<>() ;
protected boolean readonly = false ;
/** Create an empty context */
public Context() {}
/* Create an empty context, mark it's readonly state */
private Context(boolean readonly) {
this.readonly = readonly ;
}
/**
* Create a context and initialize it with a copy of the named values of
* another one. Shallow copy: the values themselves are not copied
*/
public Context(Context cxt) {
putAll(cxt) ;
}
/**
* Return a copy of this context. Modifications of the copy do not affect
* the original context.
*/
public Context copy() {
return new Context(this) ;
}
// -- basic operations
/** Get the object value of a property or null */
@SuppressWarnings("unchecked")
public T get(Symbol property) {
return (T) context.get(property) ;
}
/**
* Get the object value of a property - return the default value if not
* present .
*/
public Object get(Symbol property, Object defaultValue) {
Object x = context.get(property) ;
if ( x == null )
return defaultValue ;
return x ;
}
/** Store a named value - overwrites any previous set value */
public void put(Symbol property, Object value) {
_put(property, value) ;
doCallbacks(property) ;
}
/** Store a named value - overwrites any previous set value */
public void set(Symbol property, Object value) {
_put(property, value) ;
doCallbacks(property) ;
}
private void _put(Symbol property, Object value) {
if ( readonly )
throw new ARQException("Context is readonly") ;
if ( property == null )
throw new ARQException("Context key is null") ;
if ( value == null ) {
context.remove(property) ;
return ;
}
context.put(property, value) ;
}
/** Store a named value - overwrites any previous set value */
public void set(Symbol property, boolean value) {
if ( value )
setTrue(property) ;
else
setFalse(property) ;
}
/** Store a named value only if it is not currently set */
public void setIfUndef(Symbol property, Object value) {
Object x = context.get(property) ;
if ( x == null )
put(property, value) ;
}
/** Remove any value associated with a property */
public void remove(Symbol property) {
context.remove(property) ;
doCallbacks(property) ;
}
/** Remove any value associated with a property - alternative method name */
public void unset(Symbol property) {
context.remove(property) ;
doCallbacks(property) ;
}
// ---- Helpers
// -- Existence
/** Is a property set? */
public boolean isDefined(Symbol property) {
return context.containsKey(property) ;
}
/** Is a property not set? */
public boolean isUndef(Symbol property) {
return !isDefined(property) ;
}
// -- as string
/**
* Get the value a string (uses .toString() if the value is not null) -
* supply a default string value
*/
public String getAsString(Symbol property, String defaultValue) {
String x = getAsString(property) ;
if ( x == null )
return defaultValue ;
return x ;
}
/** Get the value a string (uses .toString() if the value is not null) */
public String getAsString(Symbol property) {
Object x = context.get(property) ;
if ( x == null )
return null ;
return x.toString() ;
}
/** Get the value as a a long value. The context entry can be a string, Integer or Long. */
public int getInt(Symbol symbol, int defaultValue) {
if ( isUndef(symbol) )
return defaultValue ;
Object obj = context.get(symbol) ;
if ( obj instanceof String ) {
return Integer.parseInt((String)obj) ;
} else if ( obj instanceof Integer ) {
return ((Integer)obj).intValue() ;
} else {
throw new ARQException("Value for "+symbol+" is not a recoginized class: "+Lib.className(obj)) ;
}
}
/** Get the value as a a long value. The context entry can be a string, Integer or Long. */
public long getLong(Symbol symbol, long defaultValue) {
if ( isUndef(symbol) )
return defaultValue ;
Object obj = context.get(symbol) ;
if ( obj instanceof String ) {
return Long.parseLong((String)obj) ;
} else if ( obj instanceof Integer ) {
return ((Integer)obj).intValue() ;
} else if ( obj instanceof Long ) {
return ((Long)obj) ;
} else {
throw new ARQException("Value for "+symbol+" is not a recoginized class: "+Lib.className(obj)) ;
}
}
public void putAll(Context other) {
if ( readonly )
throw new ARQException("Context is readonly") ;
if ( other != null ) {
for ( Map.Entry e : other.context.entrySet() )
put(e.getKey(), e.getValue()) ;
}
}
// -- true/false
/** Set propety value to be true */
public void setTrue(Symbol property) {
set(property, Boolean.TRUE) ;
}
/** Set propety value to be false */
public void setFalse(Symbol property) {
set(property, Boolean.FALSE) ;
}
/** Is the value 'true' (either set to the string "true" or Boolean.TRUE) */
public boolean isTrue(Symbol property) {
return isTrue(property, false) ;
}
/**
* Is the value 'true' (either set to the string "true" or Boolean.TRUE) or
* undefined?
*/
public boolean isTrueOrUndef(Symbol property) {
return isTrue(property, true) ;
}
private boolean isTrue(Symbol property, boolean dft) {
Object x = get(property) ;
if ( x == null )
return dft ;
if ( x instanceof String ) {
String s = (String)x ;
if ( s.equalsIgnoreCase("true") )
return true ;
}
return x.equals(Boolean.TRUE) ;
}
/** Is the value 'false' (either set to the string "false" or Boolean.FALSE) */
public boolean isFalse(Symbol property) {
return isFalse(property, false) ;
}
/**
* Is the value 'false' (either set to the string "false" or Boolean.FALSE)
* or undefined
*/
public boolean isFalseOrUndef(Symbol property) {
return isFalse(property, true) ;
}
private boolean isFalse(Symbol property, boolean dft) {
Object x = get(property) ;
if ( x == null )
return dft ;
if ( x instanceof String ) {
String s = (String)x ;
if ( s.equalsIgnoreCase("false") )
return true ;
}
return x.equals(Boolean.FALSE) ;
}
// -- Test for value
/** Test whether a named value is a specific value (.equals) */
public boolean hasValue(Symbol property, Object value) {
Object x = get(property) ;
if ( x == null && value == null )
return true ;
if ( x == null || value == null )
return false ;
return x.equals(value) ;
}
/** Test whether a named value (as a string) has a specific string form */
public boolean hasValueAsString(Symbol property, String value) {
return hasValueAsString(property, value, false) ;
}
/**
* Test whether a named value (as a string) has a specific string form - can
* ignore case
*/
public boolean hasValueAsString(Symbol property, String value, boolean ignoreCase) {
String s = getAsString(property) ;
if ( s == null && value == null )
return true ;
if ( s == null || value == null )
return false ;
if ( ignoreCase )
return s.equalsIgnoreCase(value) ;
return s.equals(value) ;
}
/** Set of properties (as Symbols) currently defined */
public Set keys() {
return context.keySet() ;
}
/** Return the number of context items */
public int size() {
return context.size() ;
}
// ---- Callbacks
public synchronized void addCallback(Callback m) {
callbacks.add(m) ;
}
public synchronized void removeCallback(Callback m) {
callbacks.remove(m) ;
}
public synchronized List> getCallbacks() {
return Collections.unmodifiableList(callbacks) ;
}
private synchronized void doCallbacks(Symbol symbol) {
for ( Callback c : callbacks ) {
c.apply(symbol) ;
}
}
@Override
public String toString() {
String x = "" ;
String sep = "" ;
for ( Symbol s : keys() ) {
Object value = get(s) ;
x = x + sep + s + " = " + value ;
sep = "\n" ;
}
return x ;
}
// Put any per-dataset execution global configuration state here.
public static Context setupContext(Context context, DatasetGraph dataset) {
if ( context == null )
context = ARQ.getContext() ; // Already copied?
context = context.copy() ;
if ( dataset != null && dataset.getContext() != null )
// Copy per-dataset settings.
context.putAll(dataset.getContext()) ;
context.set(ARQConstants.sysCurrentTime, NodeFactoryExtra.nowAsDateTime()) ;
// Allocators.
// context.set(ARQConstants.sysVarAllocNamed, new
// VarAlloc(ARQConstants.allocVarMarkerExec)) ;
// context.set(ARQConstants.sysVarAllocAnon, new
// VarAlloc(ARQConstants.allocVarAnonMarkerExec)) ;
// Add VarAlloc for variables and bNodes (this is not the parse name).
// More added later e.g. query (if there is a query), algebra form (in
// setOp)
return context ;
}
@Override
public int hashCode() {
final int prime = 31 ;
int result = 1 ;
result = prime * result + ((context == null) ? 0 : context.hashCode()) ;
result = prime * result + (readonly ? 1231 : 1237) ;
return result ;
}
@Override
public boolean equals(Object obj) {
if ( this == obj )
return true ;
if ( obj == null )
return false ;
if ( getClass() != obj.getClass() )
return false ;
Context other = (Context)obj ;
if ( context == null ) {
if ( other.context != null )
return false ;
} else if ( !context.equals(other.context) )
return false ;
if ( readonly != other.readonly )
return false ;
return true ;
}
}
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