Revision: 17565
http://sourceforge.net/p/gate/code/17565
Author: johann_p
Date: 2014-03-06 14:59:10 +0000 (Thu, 06 Mar 2014)
Log Message:
-----------
Add a utility method to resolve variables of the
form ${name} or $env{name} in Strings against
various kinds of sources for the variable values.
Modified Paths:
--------------
gate/trunk/src/main/gate/Utils.java
Modified: gate/trunk/src/main/gate/Utils.java
===================================================================
--- gate/trunk/src/main/gate/Utils.java 2014-03-06 14:53:16 UTC (rev 17564)
+++ gate/trunk/src/main/gate/Utils.java 2014-03-06 14:59:10 UTC (rev 17565)
@@ -18,6 +18,7 @@
import gate.annotation.AnnotationSetImpl;
import gate.creole.ConditionalSerialController;
import gate.creole.RunningStrategy;
+import gate.util.FeatureBearer;
import gate.util.GateRuntimeException;
import gate.util.InvalidOffsetException;
import gate.util.OffsetComparator;
@@ -1010,4 +1011,159 @@
}
}
+ /**
+ * This will replace all occurrences of variables of the form $env{name},
+ * $prop{name}, $doc{featname}, $pr_parm{inputAS} or $$env{name} etc in a
String.
+ *
+ * The source for replacing the variable can be environment variables,
+ * system properties, or arbitrary maps or resources specified when calling
+ * the method.
+ * <p>
+ * Examples:
+ * <ul>
+ * <li><code>replaceVariablesInString("text $env{GATE_HOME} more
text")</code>:
+ * returns "text /path/to/gate more text" if the environment variable
+ * "GATE_HOME" was set to "/path/to/gate"
+ * <li><code>replaceVariablesInString("text $pr{myfeature1} more
text",pr1)</code>:
+ * returns "myvalue1" if the feature map of the processing resource pr1
+ * contains an entry with key "myfeature" and value "myvalue"
+ * <li><code>replaceVariablesInString("text ${somekey} more
text",map1,map2,resource1,map3)</code>:
+ * this will
+ * find the value of an entry with key "somekey" in the first Map object
specified
+ * in the parameter list of the method.
+ * </ul>
+ * <p>
+ * The possible sources for finding values for a variable are:
+ * <ul>
+ * <li><code>System.getenv()</code>: for variables of the form $env{name}
+ * <li><code>System.getProperties()</code>: for variables of the form
$prop{name}
+ * <li><code>Resource</code>: the feature map of any resource which is
specified in the
+ * list of objects is used for variables of the form $resource{name} or
+ * for variables of the form $corpus{name} if the resource is a corpus, for
+ * $pr{name} if the resource is a processing resource and so on. If the
+ * resource is a processing resource its
+ * <li><code>FeatureMap</code> or <code>Map</code>: any feature map or
+ * Map which can be used to look up String keys can be specified
+ * as a source and will be used for variables of the form ${name}.
+ * </ul>
+ * <p>
+ * The value substituted is converted to a string using the toString()
+ * method of whatever object is stored in the map. If the value returned
+ * by Map.get(key) is null, no substitution is carried out and the
+ * variable is left unchanged in the string.
+ * <p>
+ * The following variable constructs are supported:
+ * <ul>
+ * <li>$env{name} will be replaced with the value from the environment
variables map
+ * from System.getenv() and nothing else.
+ * <li>$prop{name} will be replaced with the value of the properties map
+ * from System.getProperties() and nothing else.
+ * <li>$controller{name} will be replaced with the value of a feature from
the FeatureMap
+ * of the first resource of type Controller found in the argument list.
+ * <li>$corpus{name} will be replaced with the value of a feature from the
FeatureMap
+ * of the first resource of type Corpus found in the argument list.
+ * <li>$pr{name} will be replaced with the value of a feature from the
FeatureMap
+ * of the first resource of type ProcessingResource found in the argument
list.
+ * <li>$pr_parm{name} will be replaced with the value of the parameter 'name'
+ * of the first resource of type ProcessingResource found in the argument
list.
+ * This can be especially useful to replace a variable in one parameter with
+ * the value of another, potentially hidden, parameter of the same PR.
+ * <li>$doc{name} will be replaced with the value of a feature from the
FeatureMap
+ * of the first resource of type Document found in the argument list.
+ * <li>$resource{name} will be replaced with the value of a feature from the
FeatureMap
+ * of the first resource of type Resource found in the argument list.
+ * </ul>
+ * <p>
+ * If two dollar characters are used instead of one, the replacement string
+ * will in turn be subject to replacement, e.g. $$env{abc} could get replaced
+ * with the replacement string '$corpus{f1}' which would in turn get replaced
+ * with the value of the feature 'f1' from the feature set of the first
+ * corpus in the parameter list that has a value for that feature.
+ *
+ */
+ public static String replaceVariablesInString(
+ String string, Object... sources)
+ {
+ Matcher matcher =
Pattern.compile("(\\$\\$?)([a-zA-Z]*)\\{([^}]+)\\}").matcher(string);
+ int findFrom = 0;
+ int lastEnd = 0;
+ StringBuilder sb = new StringBuilder(string.length()*2);
+ while(findFrom < string.length() && matcher.find(findFrom)) {
+ String dollars = matcher.group(1);
+ String type = matcher.group(2);
+ String varname = matcher.group(3);
+ int matchStart = matcher.start();
+ // whenever we have found something, we can immediately move the part
+ // from the last end of match to the new start of match to the
+ // return string, that is just unmodified string ...
+ // But only if the length is > 0
+ if((matchStart - lastEnd) > 0) {
+ sb.append(string.substring(lastEnd,matchStart));
+ }
+ lastEnd = matcher.end();
+ Object value = null;
+ // for each match we find, go through all the sources in the order
+ // listed and if the type of the source matches the requested type
+ // then try to look the variable up. If we find something use it and
+ // finish looking, otherwise continue until all sources have been
+ // exhausted.
+ // A variable where no value has been found anywhere is not replaced.
+ // If a variable got replaced and it was a variable that started with
+ // two dollar signs, then the replacement value is first getting
+ // recursively replaced too.
+ if(type.equals("env")) {
+ value = System.getenv().get(varname);
+ } else if(type.equals("prop")) {
+ value = System.getProperties().get(varname);
+ } else {
+ for(Object source : sources) {
+ if(type.isEmpty()) { // an empty variable type matches only maps
from the sources
+ if(source instanceof Map) {
+ value = ((Map)source).get(varname);
+ }
+ } else if(type.equals("pr") && (source instanceof
ProcessingResource)) {
+ value = ((FeatureBearer)source).getFeatures().get(varname);
+ } else if(type.equals("pr_parm") && (source instanceof
ProcessingResource)) {
+ try {
+ value = ((ProcessingResource)source).getParameterValue(varname);
+ } catch(Exception ex) {
+ // do nothing, leave the value null
+ }
+ } else if(type.equals("doc") && (source instanceof Document)) {
+ value = ((FeatureBearer)source).getFeatures().get(varname);
+ } else if(type.equals("controller") && (source instanceof
Controller)) {
+ value = ((FeatureBearer)source).getFeatures().get(varname);
+ } else if(type.equals("corpus") && (source instanceof Corpus)) {
+ value = ((FeatureBearer)source).getFeatures().get(varname);
+ } else if(type.equals("resource") && (source instanceof Resource)) {
+ value = ((FeatureBearer)source).getFeatures().get(varname);
+ }
+ if(value != null) {
+ break;
+ }
+ } // for source : sources
+ }
+ // only do anything at all if we found a value for this parameter
+ if(value != null) {
+ String replacement = value.toString();
+ // if we had double-dollars, first do the recursive replacement ...
+ if(dollars.equals("$$")) {
+ replacement = replaceVariablesInString(replacement, sources);
+ }
+ sb.append(replacement);
+ } else {
+ sb.append(matcher.group());
+ // the first character after the match
+ }
+ findFrom = matcher.end();
+ } // while matcher.find ...
+ // if we have some unmatched string left over, append it too
+ if(lastEnd < string.length()) {
+ sb.append(string.substring(lastEnd));
+ }
+ return sb.toString();
+ }
+
+
+
}
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