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DATACOUCH-166 - Improve SpEL support, prefix is now #{

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This commit is contained in:
Simon Baslé
2015-11-16 13:54:43 +01:00
parent 2f68740247
commit 2378e7145b
6 changed files with 40 additions and 109 deletions
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2
src/main/java/org/springframework/data/couchbase/core/query/Query.java
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@@ -34,7 +34,7 @@ import org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery;
* <p/>
* In this case, one can use a placeholder notation of {@code ?0}, {@code ?1} and so on.
* <p/>
* Also, SpEL in the form <code>${spelExpression}</code> is supported, including the
* Also, SpEL in the form <code>#{spelExpression}</code> is supported, including the
* following N1QL variables that will be replaced by the underlying {@link CouchbaseTemplate}
* associated information:
* <ul>

93
src/main/java/org/springframework/data/couchbase/repository/query/StringN1qlBasedQuery.java
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@@ -28,6 +28,7 @@ import org.springframework.data.repository.query.ParameterAccessor;
import org.springframework.data.repository.query.RepositoryQuery;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.common.TemplateParserContext;
import org.springframework.expression.spel.standard.SpelExpressionParser;
/**
@@ -36,8 +37,9 @@ import org.springframework.expression.spel.standard.SpelExpressionParser;
* The statement can contain positional placeholders (eg. <code>name = $1</code>) that will map to the
* method's parameters, in the same order.
* <p/>
* The statement can also contain SpEL expressions enclosed in <code>${}</code>.
* <p/> There are couchbase-provided variables included for the {@link #SPEL_BUCKET bucket namespace},
* The statement can also contain SpEL expressions enclosed in <code>#{</code> and <code>}</code>.
* <p/>
* There are couchbase-provided variables included for the {@link #SPEL_BUCKET bucket namespace},
* the {@link #SPEL_ENTITY ID and CAS fields} necessary for entity reconstruction
* or a shortcut that covers {@link #SPEL_SELECT_FROM_CLAUSE SELECT AND FROM clauses},
* along with a variable for {@link #SPEL_FILTER WHERE clause filtering} of the correct entity.
@@ -54,7 +56,7 @@ public class StringN1qlBasedQuery extends AbstractN1qlBasedQuery {
/**
* Use this variable in a SpEL expression in a {@link org.springframework.data.couchbase.core.query.Query @Query}
* annotation's inline statement. This will be replaced by the correct <code>SELECT x FROM y</code> clause needed
* for entity mapping. Eg. <code>"${{@value StringN1qlBasedQuery#SPEL_SELECT_FROM_CLAUSE}} WHERE test = true"</code>.
* for entity mapping. Eg. <code>"#{{@value StringN1qlBasedQuery#SPEL_SELECT_FROM_CLAUSE}} WHERE test = true"</code>.
* Note this only makes sense once, as the beginning of the statement.
*/
public static final String SPEL_SELECT_FROM_CLAUSE = "#" + SPEL_PREFIX + ".selectEntity";
@@ -62,21 +64,21 @@ public class StringN1qlBasedQuery extends AbstractN1qlBasedQuery {
/**
* Use this variable in a SpEL expression in a {@link org.springframework.data.couchbase.core.query.Query @Query}
* annotation's inline statement. This will be replaced by the (escaped) bucket name corresponding to the repository's
* entity. Eg. <code>"SELECT * FROM ${{@value StringN1qlBasedQuery#SPEL_BUCKET}} LIMIT 3"</code>.
* entity. Eg. <code>"SELECT * FROM #{{@value StringN1qlBasedQuery#SPEL_BUCKET}} LIMIT 3"</code>.
*/
public static final String SPEL_BUCKET = "#" + SPEL_PREFIX + ".bucket";
/**
* Use this variable in a SpEL expression in a {@link org.springframework.data.couchbase.core.query.Query @Query}
* annotation's inline statement. This will be replaced by the fields allowing to construct the repository's entity
* (SELECT clause). Eg. <code>"SELECT ${{@value StringN1qlBasedQuery#SPEL_ENTITY}} FROM test"</code>.
* (SELECT clause). Eg. <code>"SELECT #{{@value StringN1qlBasedQuery#SPEL_ENTITY}} FROM test"</code>.
*/
public static final String SPEL_ENTITY = "#" + SPEL_PREFIX + ".fields";
/**
* Use this variable in a SpEL expression in a {@link org.springframework.data.couchbase.core.query.Query @Query}
* annotation's inline statement WHERE clause. This will be replaced by the expression allowing to only select
* documents matching the entity's class. Eg. <code>"SELECT * FROM test WHERE test = true AND ${{@value StringN1qlBasedQuery#SPEL_FILTER}}"</code>.
* documents matching the entity's class. Eg. <code>"SELECT * FROM test WHERE test = true AND #{{@value StringN1qlBasedQuery#SPEL_FILTER}}"</code>.
*/
public static final String SPEL_FILTER = "#" + SPEL_PREFIX + ".filter";
@@ -123,81 +125,28 @@ public class StringN1qlBasedQuery extends AbstractN1qlBasedQuery {
}
/**
* Parse the statement to detect SPEL expressions (delimited by <code>${</code> and <code>}</code>)
* and replace said expressions with their corresponding values (see {@link #evaluateSpelExpression(String, boolean, Object[])}).
* Parse the statement to detect SPEL blocks (delimited by <code>#{</code> and <code>}</code>)
* and replace said expression blocks with their corresponding values.
*
* @param statement the full statement into which SpEL expressions should be parsed and replaced.
* @param runtimeParameters the parameters passed into the method at runtime.
* @return the statement with the SpEL interpreted and replaced by its values.
*/
protected String parseSpel(String statement, boolean isCount, Object[] runtimeParameters) {
StringBuilder parsed = new StringBuilder(statement);
int currentIndex = 0;
while(currentIndex > -1 && currentIndex < parsed.length()) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Evaluating from index {}, {}", currentIndex, parsed.substring(currentIndex));
}
int opening = parsed.indexOf("${", currentIndex);
if (opening == -1) {
break;
} else {
//find the end of the ${ } expression, eat inner braces
int closing = opening + 2;
int curlyBraceOpenCnt = 1;
while (curlyBraceOpenCnt > 0) {
switch (parsed.charAt(closing++)) {
case '{':
curlyBraceOpenCnt++;
break;
case '}':
curlyBraceOpenCnt--;
break;
default:
}
}
//we're now at the end of the expression
//evaluate and replace
String expression = parsed.substring(opening + 2, closing - 1);
String replacement = evaluateSpelExpression(expression, isCount, runtimeParameters);
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Replacing SPEL \"{}\" with value \"{}\"", expression, replacement);
}
parsed.replace(opening, closing, replacement);
//move on
currentIndex = opening + replacement.length();
}
}
return parsed.toString();
}
/**
* This method is in charge of evaluating a single SPEL expression (as delimited by <code>${</code> and <code>}</code>)
* and returning the corresponding computed value.
*
* @param expression the SPEL expression.
* @param runtimeParameters the parameters using during method call.
* @return the corresponding value.
*/
protected String evaluateSpelExpression(String expression, boolean isCount, Object[] runtimeParameters) {
EvaluationContext evaluationContext = evaluationContextProvider.getEvaluationContext(getQueryMethod().getParameters(), runtimeParameters);
Expression parsedExpression = parser.parseExpression(expression);
N1qlSpelValues n1qlSpelValues = this.statementContext;
if (isCount) {
n1qlSpelValues = this.countContext;
}
return doEvaluate(evaluationContext, parsedExpression, n1qlSpelValues);
return doParse(statement, parser, evaluationContext, n1qlSpelValues);
}
protected static String doEvaluate(EvaluationContext context, Expression parsedExpression, N1qlSpelValues spelValues) {
context.setVariable(SPEL_PREFIX, spelValues);
return parsedExpression.getValue(context, String.class);
//this static method can be used to test the parsing behavior for Couchbase specific spel variables
//in isolation from the rest of the spel parser initialization chain.
protected static String doParse(String statement, SpelExpressionParser parser, EvaluationContext evaluationContext, N1qlSpelValues n1qlSpelValues) {
Expression parsedExpression = parser.parseExpression(statement, new TemplateParserContext());
evaluationContext.setVariable(SPEL_PREFIX, n1qlSpelValues);
return parsedExpression.getValue(evaluationContext, String.class);
}
@Override
@@ -228,25 +177,25 @@ public class StringN1qlBasedQuery extends AbstractN1qlBasedQuery {
public static final class N1qlSpelValues {
/**
* <code>${{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* <code>#{{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* selectEntity</code> will be replaced by the SELECT-FROM clause corresponding to the entity. Use once at the beginning.
*/
public final String selectEntity;
/**
* <code>${{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* <code>#{{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* fields</code> will be replaced by the list of N1QL fields allowing to reconstruct the entity.
*/
public final String fields;
/**
* <code>${{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* <code>#{{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* bucket</code> will be replaced by (escaped) bucket name in which the entity is stored.
*/
public final String bucket;
/**
* <code>${{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* <code>#{{@value org.springframework.data.couchbase.repository.query.StringN1qlBasedQuery#SPEL_PREFIX}.
* filter</code> will be replaced by an expression allowing to select only entries matching the entity in a WHERE clause.
*/
public final String filter;