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ggregory pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
new 1242858 Make it easier to subclass and compose StringSubstitutor.
1242858 is described below
commit 12428582b46e9e3ce0dff65e25c51a71083c19b7
Author: Gary Gregory <[email protected]>
AuthorDate: Sun Jul 5 11:02:53 2020 -0400
Make it easier to subclass and compose StringSubstitutor.
---
.../org/apache/commons/text/StringSubstitutor.java | 206 ++++++++++++---------
.../apache/commons/text/StringSubstitutorTest.java | 14 ++
2 files changed, 132 insertions(+), 88 deletions(-)
diff --git a/src/main/java/org/apache/commons/text/StringSubstitutor.java
b/src/main/java/org/apache/commons/text/StringSubstitutor.java
index 8acf438..82e64c9 100644
--- a/src/main/java/org/apache/commons/text/StringSubstitutor.java
+++ b/src/main/java/org/apache/commons/text/StringSubstitutor.java
@@ -142,20 +142,16 @@ import
org.apache.commons.text.matcher.StringMatcherFactory;
* <pre>
* final StringSubstitutor interpolator =
StringSubstitutor.createInterpolator();
* interpolator.setEnableSubstitutionInVariables(true); // Allows for nested
$'s.
- * final String text = interpolator.replace(
- * "Base64 Decoder: ${base64Decoder:SGVsbG9Xb3JsZCE=}\n"
+ * final String text = interpolator.replace("Base64 Decoder:
${base64Decoder:SGVsbG9Xb3JsZCE=}\n"
* + "Base64 Encoder: ${base64Encoder:HelloWorld!}\n"
* + "Java Constant: ${const:java.awt.event.KeyEvent.VK_ESCAPE}\n"
- * + "Date: ${date:yyyy-MM-dd}\n"
- * + "DNS: ${dns:address|apache.org}\n"
+ * + "Date: ${date:yyyy-MM-dd}\n" + "DNS:
${dns:address|apache.org}\n"
* + "Environment Variable: ${env:USERNAME}\n"
* + "File Content:
${file:UTF-8:src/test/resources/document.properties}\n"
- * + "Java: ${java:version}\n"
- * + "Localhost: ${localhost:canonical-name}\n"
+ * + "Java: ${java:version}\n" + "Localhost:
${localhost:canonical-name}\n"
* + "Properties File:
${properties:src/test/resources/document.properties::mykey}\n"
* + "Resource Bundle:
${resourceBundle:org.example.testResourceBundleLookup:mykey}\n"
- * + "Script: ${script:javascript:3 + 4}\n"
- * + "System Property: ${sys:user.dir}\n"
+ * + "Script: ${script:javascript:3 + 4}\n" + "System
Property: ${sys:user.dir}\n"
* + "URL Decoder: ${urlDecoder:Hello%20World%21}\n"
* + "URL Encoder: ${urlEncoder:Hello World!}\n"
* + "URL Content (HTTP): ${url:UTF-8:http://www.apache.org}\n";
@@ -169,9 +165,9 @@ import org.apache.commons.text.matcher.StringMatcherFactory;
*
* <h2>Using Recursive Variable Replacement</h2>
* <p>
- * Variable replacement can work recursively by calling {@link
#setEnableSubstitutionInVariables(boolean)}
- * with {@code true}. If a variable value contains a variable then that
variable will
- * also be replaced. Cyclic replacements are detected and will throw an
exception.
+ * Variable replacement can work recursively by calling {@link
#setEnableSubstitutionInVariables(boolean)} with
+ * {@code true}. If a variable value contains a variable then that variable
will also be replaced. Cyclic replacements
+ * are detected and will throw an exception.
* </p>
* <p>
* You can get the replace result to contain a variable prefix. For example:
@@ -222,6 +218,35 @@ import
org.apache.commons.text.matcher.StringMatcherFactory;
public class StringSubstitutor {
/**
+ * The low-level result of a substitution.
+ *
+ * @since 1.9
+ */
+ public static class Result {
+
+ /** Whether the buffer is altered. */
+ public final boolean altered;
+
+ /** The length of change. */
+ public final int lengthChange;
+
+ /** The starting position of last variable seen. */
+ public final int startVarPos;
+
+ private Result(final boolean altered, final int lengthChange, final
int startVarPos) {
+ super();
+ this.altered = altered;
+ this.lengthChange = lengthChange;
+ this.startVarPos = startVarPos;
+ }
+ }
+
+ /**
+ * Constant for the default escape character.
+ */
+ public static final char DEFAULT_ESCAPE = '$';
+
+ /**
* The default variable default separator.
*
* @since 1.5.
@@ -243,11 +268,6 @@ public class StringSubstitutor {
public static final String DEFAULT_VAR_START = "${";
/**
- * Constant for the default escape character.
- */
- public static final char DEFAULT_ESCAPE = '$';
-
- /**
* Constant for the default variable prefix.
*/
public static final StringMatcher DEFAULT_PREFIX =
StringMatcherFactory.INSTANCE.stringMatcher(DEFAULT_VAR_START);
@@ -261,7 +281,7 @@ public class StringSubstitutor {
* Constant for the default value delimiter of a variable.
*/
public static final StringMatcher DEFAULT_VALUE_DELIMITER =
StringMatcherFactory.INSTANCE
- .stringMatcher(DEFAULT_VAR_DEFAULT);
+ .stringMatcher(DEFAULT_VAR_DEFAULT);
/**
* Creates a new instance using the interpolator string lookup
@@ -271,8 +291,8 @@ public class StringSubstitutor {
* </p>
*
* <pre>
- * StringSubstitutor.createInterpolator()
- * .replace("OS name: ${sys:os.name}, " + "3 + 4 = ${script:javascript:3
+ 4}");
+ * StringSubstitutor.createInterpolator().replace(
+ * "OS name: ${sys:os.name}, " + "3 + 4 = ${script:javascript:3 + 4}");
* </pre>
*
* @return a new instance using the interpolator string lookup.
@@ -286,8 +306,8 @@ public class StringSubstitutor {
/**
* Replaces all the occurrences of variables in the given source object
with their matching values from the map.
*
- * @param <V> the type of the values in the map
- * @param source the source text containing the variables to substitute,
null returns null
+ * @param <V> the type of the values in the map
+ * @param source the source text containing the variables to substitute,
null returns null
* @param valueMap the map with the values, may be null
* @return The result of the replace operation
* @throws IllegalArgumentException if a variable is not found and
enableUndefinedVariableException is true
@@ -300,17 +320,17 @@ public class StringSubstitutor {
* Replaces all the occurrences of variables in the given source object
with their matching values from the map.
* This method allows to specify a custom variable prefix and suffix
*
- * @param <V> the type of the values in the map
- * @param source the source text containing the variables to substitute,
null returns null
+ * @param <V> the type of the values in the map
+ * @param source the source text containing the variables to substitute,
null returns null
* @param valueMap the map with the values, may be null
- * @param prefix the prefix of variables, not null
- * @param suffix the suffix of variables, not null
+ * @param prefix the prefix of variables, not null
+ * @param suffix the suffix of variables, not null
* @return The result of the replace operation
* @throws IllegalArgumentException if the prefix or suffix is null
* @throws IllegalArgumentException if a variable is not found and
enableUndefinedVariableException is true
*/
public static <V> String replace(final Object source, final Map<String, V>
valueMap, final String prefix,
- final String suffix) {
+ final String suffix) {
return new StringSubstitutor(valueMap, prefix, suffix).replace(source);
}
@@ -318,7 +338,7 @@ public class StringSubstitutor {
* Replaces all the occurrences of variables in the given source object
with their matching values from the
* properties.
*
- * @param source the source text containing the variables to
substitute, null returns null
+ * @param source the source text containing the variables to substitute,
null returns null
* @param valueProperties the properties with values, may be null
* @return The result of the replace operation
* @throws IllegalArgumentException if a variable is not found and
enableUndefinedVariableException is true
@@ -405,7 +425,7 @@ public class StringSubstitutor {
* Creates a new instance and initializes it. Uses defaults for variable
prefix and suffix and the escaping
* character.
*
- * @param <V> the type of the values in the map
+ * @param <V> the type of the values in the map
* @param valueMap the map with the variables' values, may be null
*/
public <V> StringSubstitutor(final Map<String, V> valueMap) {
@@ -415,10 +435,10 @@ public class StringSubstitutor {
/**
* Creates a new instance and initializes it. Uses a default escaping
character.
*
- * @param <V> the type of the values in the map
+ * @param <V> the type of the values in the map
* @param valueMap the map with the variables' values, may be null
- * @param prefix the prefix for variables, not null
- * @param suffix the suffix for variables, not null
+ * @param prefix the prefix for variables, not null
+ * @param suffix the suffix for variables, not null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public <V> StringSubstitutor(final Map<String, V> valueMap, final String
prefix, final String suffix) {
@@ -428,31 +448,31 @@ public class StringSubstitutor {
/**
* Creates a new instance and initializes it.
*
- * @param <V> the type of the values in the map
+ * @param <V> the type of the values in the map
* @param valueMap the map with the variables' values, may be null
- * @param prefix the prefix for variables, not null
- * @param suffix the suffix for variables, not null
- * @param escape the escape character
+ * @param prefix the prefix for variables, not null
+ * @param suffix the suffix for variables, not null
+ * @param escape the escape character
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public <V> StringSubstitutor(final Map<String, V> valueMap, final String
prefix, final String suffix,
- final char escape) {
+ final char escape) {
this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix,
suffix, escape);
}
/**
* Creates a new instance and initializes it.
*
- * @param <V> the type of the values in the map
- * @param valueMap the map with the variables' values, may be null
- * @param prefix the prefix for variables, not null
- * @param suffix the suffix for variables, not null
- * @param escape the escape character
+ * @param <V> the type of the values in the map
+ * @param valueMap the map with the variables' values, may be null
+ * @param prefix the prefix for variables, not null
+ * @param suffix the suffix for variables, not null
+ * @param escape the escape character
* @param valueDelimiter the variable default value delimiter, may be null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public <V> StringSubstitutor(final Map<String, V> valueMap, final String
prefix, final String suffix,
- final char escape, final String valueDelimiter) {
+ final char escape, final String valueDelimiter) {
this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix,
suffix, escape, valueDelimiter);
}
@@ -469,13 +489,13 @@ public class StringSubstitutor {
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
- * @param prefix the prefix for variables, not null
- * @param suffix the suffix for variables, not null
- * @param escape the escape character
+ * @param prefix the prefix for variables, not null
+ * @param suffix the suffix for variables, not null
+ * @param escape the escape character
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StringSubstitutor(final StringLookup variableResolver, final String
prefix, final String suffix,
- final char escape) {
+ final char escape) {
this.setVariableResolver(variableResolver);
this.setVariablePrefix(prefix);
this.setVariableSuffix(suffix);
@@ -487,14 +507,14 @@ public class StringSubstitutor {
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
- * @param prefix the prefix for variables, not null
- * @param suffix the suffix for variables, not null
- * @param escape the escape character
- * @param valueDelimiter the variable default value delimiter string,
may be null
+ * @param prefix the prefix for variables, not null
+ * @param suffix the suffix for variables, not null
+ * @param escape the escape character
+ * @param valueDelimiter the variable default value delimiter string, may
be null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StringSubstitutor(final StringLookup variableResolver, final String
prefix, final String suffix,
- final char escape, final String valueDelimiter) {
+ final char escape, final String valueDelimiter) {
this.setVariableResolver(variableResolver);
this.setVariablePrefix(prefix);
this.setVariableSuffix(suffix);
@@ -506,28 +526,28 @@ public class StringSubstitutor {
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
- * @param prefixMatcher the prefix for variables, not null
- * @param suffixMatcher the suffix for variables, not null
- * @param escape the escape character
+ * @param prefixMatcher the prefix for variables, not null
+ * @param suffixMatcher the suffix for variables, not null
+ * @param escape the escape character
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StringSubstitutor(final StringLookup variableResolver, final
StringMatcher prefixMatcher,
- final StringMatcher suffixMatcher, final char escape) {
+ final StringMatcher suffixMatcher, final char escape) {
this(variableResolver, prefixMatcher, suffixMatcher, escape,
DEFAULT_VALUE_DELIMITER);
}
/**
* Creates a new instance and initializes it.
*
- * @param variableResolver the variable resolver, may be null
- * @param prefixMatcher the prefix for variables, not null
- * @param suffixMatcher the suffix for variables, not null
- * @param escape the escape character
+ * @param variableResolver the variable resolver, may be null
+ * @param prefixMatcher the prefix for variables, not null
+ * @param suffixMatcher the suffix for variables, not null
+ * @param escape the escape character
* @param valueDelimiterMatcher the variable default value delimiter
matcher, may be null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StringSubstitutor(final StringLookup variableResolver, final
StringMatcher prefixMatcher,
- final StringMatcher suffixMatcher, final char escape, final
StringMatcher valueDelimiterMatcher) {
+ final StringMatcher suffixMatcher, final char escape, final
StringMatcher valueDelimiterMatcher) {
this.setVariableResolver(variableResolver);
this.setVariablePrefixMatcher(prefixMatcher);
this.setVariableSuffixMatcher(suffixMatcher);
@@ -539,7 +559,6 @@ public class StringSubstitutor {
* Creates a new instance based on the given StringSubstitutor.
*
* @param other The StringSubstitutor is use as the source.
- *
* @since 1.9
*/
public StringSubstitutor(final StringSubstitutor other) {
@@ -557,7 +576,7 @@ public class StringSubstitutor {
/**
* Checks if the specified variable is already in the stack (list) of
variables.
*
- * @param varName the variable name to check
+ * @param varName the variable name to check
* @param priorVariables the list of prior variables
*/
private void checkCyclicSubstitution(final String varName, final
List<String> priorVariables) {
@@ -582,7 +601,19 @@ public class StringSubstitutor {
return this.escapeChar;
}
- // Resolver
+ /**
+ * Gets the minimum expression length based on the size of the prefix
matcher and suffix matcher.
+ * <p>
+ * By default, {@code 4}, as the shortest variable name length is 1, for
example, {@code "${k}"}.
+ * </p>
+ *
+ * @return the minimum expression length.
+ * @since 1.9
+ */
+ public int getMinExpressionLength() {
+ return getVariablePrefixMatcher().size() + 1 +
getVariableSuffixMatcher().size();
+ }
+
/**
* Gets the StringLookup that is used to lookup variables.
*
@@ -592,7 +623,6 @@ public class StringSubstitutor {
return this.variableResolver;
}
- // Variable Default Value Delimiter
/**
* Gets the variable default value delimiter matcher currently in use.
* <p>
@@ -1035,13 +1065,13 @@ public class StringSubstitutor {
* </p>
*
* @param variableName the name of the variable, not null
- * @param buf the buffer where the substitution is occurring, not
null
- * @param startPos the start position of the variable including the
prefix, valid
- * @param endPos the end position of the variable including the
suffix, valid
+ * @param buf the buffer where the substitution is occurring, not null
+ * @param startPos the start position of the variable including the
prefix, valid
+ * @param endPos the end position of the variable including the suffix,
valid
* @return The variable's value or <b>null</b> if the variable is unknown
*/
protected String resolveVariable(final String variableName, final
TextStringBuilder buf, final int startPos,
- final int endPos) {
+ final int endPos) {
final StringLookup resolver = getStringLookup();
if (resolver == null) {
return null;
@@ -1098,10 +1128,9 @@ public class StringSubstitutor {
/**
* Sets a flag controlling whether escapes are preserved during
substitution. If set to <b>true</b>, the escape
- * character is retained during substitution (e.g. {@code
$${this-is-escaped}} remains
- * {@code $${this-is-escaped}}). If set to <b>false</b>, the escape
character is removed during substitution
- * (e.g. {@code $${this-is-escaped}} becomes {@code ${this-is-escaped}}).
The default value is
- * <b>false</b>
+ * character is retained during substitution (e.g. {@code
$${this-is-escaped}} remains {@code $${this-is-escaped}}).
+ * If set to <b>false</b>, the escape character is removed during
substitution (e.g. {@code $${this-is-escaped}}
+ * becomes {@code ${this-is-escaped}}). The default value is <b>false</b>
*
* @param preserveEscapes true if escapes are to be preserved
* @return this, to enable chaining
@@ -1283,28 +1312,28 @@ public class StringSubstitutor {
* </p>
*
* @param builder the string builder to substitute into, not null
- * @param offset the start offset within the builder, must be valid
- * @param length the length within the builder to be processed, must be
valid
+ * @param offset the start offset within the builder, must be valid
+ * @param length the length within the builder to be processed, must be
valid
* @return true if altered
*/
protected boolean substitute(final TextStringBuilder builder, final int
offset, final int length) {
- return substitute(builder, offset, length, null) > 0;
+ return substitute(builder, offset, length, null).altered;
}
/**
* Recursive handler for multiple levels of interpolation. This is the
main interpolation method, which resolves the
* values of all variable references contained in the passed in text.
*
- * @param builder the string builder to substitute into, not null
- * @param offset the start offset within the builder, must be valid
- * @param length the length within the builder to be processed,
must be valid
+ * @param builder the string builder to substitute into, not null
+ * @param offset the start offset within the builder, must be valid
+ * @param length the length within the builder to be processed, must be
valid
* @param priorVariables the stack keeping track of the replaced
variables, may be null
- * @return The length change that occurs, unless priorVariables is null
when the int represents a boolean flag as to
- * whether any change occurred.
+ * @return The result.
* @throws IllegalArgumentException if variable is not found when its
allowed to throw exception
+ * @since 1.9
*/
- private int substitute(final TextStringBuilder builder, final int offset,
final int length,
- List<String> priorVariables) {
+ protected Result substitute(final TextStringBuilder builder, final int
offset, final int length,
+ List<String> priorVariables) {
Objects.requireNonNull(builder, "builder");
final StringMatcher prefixMatcher = getVariablePrefixMatcher();
final StringMatcher suffixMatcher = getVariableSuffixMatcher();
@@ -1315,11 +1344,11 @@ public class StringSubstitutor {
final boolean undefinedVariableException =
isEnableUndefinedVariableException();
final boolean preserveEscapes = isPreserveEscapes();
- final boolean top = priorVariables == null;
boolean altered = false;
int lengthChange = 0;
int bufEnd = offset + length;
int pos = offset;
+ int startVarPos = -1;
while (pos < bufEnd) {
final int startMatchLen = prefixMatcher.isMatch(builder, pos,
offset, bufEnd);
if (startMatchLen == 0) {
@@ -1340,6 +1369,7 @@ public class StringSubstitutor {
bufEnd--;
} else {
// find suffix
+ startVarPos = pos;
final int startPos = pos;
pos += startMatchLen;
int endMatchLen = 0;
@@ -1409,13 +1439,15 @@ public class StringSubstitutor {
if (varValue == null) {
varValue = varDefaultValue;
}
+ startVarPos = -1;
if (varValue != null) {
+ startVarPos = startPos;
final int varLen = varValue.length();
builder.replace(startPos, endPos,
varValue);
altered = true;
int change = 0;
if (!substitutionInValuesDisabled) { //
recursive replace
- change = substitute(builder, startPos,
varLen, priorVariables);
+ change = substitute(builder, startPos,
varLen, priorVariables).lengthChange;
}
change = change + varLen - (endPos -
startPos);
pos += change;
@@ -1429,6 +1461,7 @@ public class StringSubstitutor {
// remove variable from the cyclic stack
priorVariables.remove(priorVariables.size() -
1);
+ startVarPos = -1;
break;
}
nestedVarCount--;
@@ -1438,9 +1471,6 @@ public class StringSubstitutor {
}
}
}
- if (top) {
- return altered ? 1 : 0;
- }
- return lengthChange;
+ return new Result(altered, lengthChange, startVarPos);
}
}
diff --git a/src/test/java/org/apache/commons/text/StringSubstitutorTest.java
b/src/test/java/org/apache/commons/text/StringSubstitutorTest.java
index ae9834f..3aaac8d 100644
--- a/src/test/java/org/apache/commons/text/StringSubstitutorTest.java
+++ b/src/test/java/org/apache/commons/text/StringSubstitutorTest.java
@@ -224,6 +224,20 @@ public class StringSubstitutorTest {
target.getValueDelimiterMatcher().toString());
}
+ @Test
+ public void testGetMinExpressionLength() throws IOException {
+ final StringSubstitutor sub = new StringSubstitutor();
+ assertEquals(4, sub.getMinExpressionLength());
+ sub.setVariablePrefix('a');
+ assertEquals(3, sub.getMinExpressionLength());
+ sub.setVariablePrefix("abc");
+ assertEquals(5, sub.getMinExpressionLength());
+ sub.setVariableSuffix("xyz");
+ assertEquals(7, sub.getMinExpressionLength());
+ sub.setVariablePrefix(StringUtils.EMPTY);
+ sub.setVariableSuffix(StringUtils.EMPTY);
+ assertEquals(1, sub.getMinExpressionLength());
+ }
/**
* Tests get set.
